| blob | 0141c53b617c87e7ac3afac1fa7e7a5bfca1a474 |
1 /* Handle parameterized types (templates) for GNU -*- C++ -*-.
2 Copyright (C) 1992-2024 Free Software Foundation, Inc.
3 Written by Ken Raeburn (raeburn@cygnus.com) while at Watchmaker Computing.
4 Rewritten by Jason Merrill (jason@cygnus.com).
6 This file is part of GCC.
8 GCC is free software; you can redistribute it and/or modify
9 it under the terms of the GNU General Public License as published by
10 the Free Software Foundation; either version 3, or (at your option)
11 any later version.
13 GCC is distributed in the hope that it will be useful,
14 but WITHOUT ANY WARRANTY; without even the implied warranty of
15 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
16 GNU General Public License for more details.
18 You should have received a copy of the GNU General Public License
19 along with GCC; see the file COPYING3. If not see
20 <http://www.gnu.org/licenses/>. */
22 /* Known bugs or deficiencies include:
24 all methods must be provided in header files; can't use a source
25 file that contains only the method templates and "just win".
27 Fixed by: C++20 modules. */
53 /* The type of functions taking a tree, and some additional data, and
54 returning an int. */
57 /* The PENDING_TEMPLATES is a list of templates whose instantiations
58 have been deferred, either because their definitions were not yet
59 available, or because we were putting off doing the work. */
61 {
64 };
78 /* Live only within one (recursive) call to tsubst_expr. We use
79 this to pass the statement expression node from the STMT_EXPR
80 to the EXPR_STMT that is its result. */
83 // -------------------------------------------------------------------------- //
84 // Local Specialization Stack
85 //
86 // Implementation of the RAII helper for creating new local
87 // specializations.
90 {
92 ;
95 else
97 }
100 {
102 {
105 }
106 }
108 /* True if we've recursed into fn_type_unification too many times. */
112 {
116 };
118 /* The general template is not in these tables. */
123 /* Contains canonical template parameter types. The vector is indexed by
124 the TEMPLATE_TYPE_IDX of the template parameter. Each element is a
125 TREE_LIST, whose TREE_VALUEs contain the canonical template
126 parameters of various types and levels. */
129 #define UNIFY_ALLOW_NONE 0
130 #define UNIFY_ALLOW_MORE_CV_QUAL 1
131 #define UNIFY_ALLOW_LESS_CV_QUAL 2
132 #define UNIFY_ALLOW_DERIVED 4
133 #define UNIFY_ALLOW_INTEGER 8
134 #define UNIFY_ALLOW_OUTER_LEVEL 16
135 #define UNIFY_ALLOW_OUTER_MORE_CV_QUAL 32
136 #define UNIFY_ALLOW_OUTER_LESS_CV_QUAL 64
139 tbr_incomplete_type,
140 tbr_ambiguous_baseclass,
141 tbr_success
142 };
229 /* Make the current scope suitable for access checking when we are
230 processing T. T can be FUNCTION_DECL for instantiated function
231 template, VAR_DECL for static member variable, or TYPE_DECL for
232 for a class or alias template (needed by instantiate_decl). */
234 void
236 {
248 /* An artificial deduction guide should have the same access as
249 the constructor. */
251 else
255 {
258 }
259 }
261 /* Restore the scope set up by push_access_scope. T is the node we
262 are processing. */
264 void
266 {
276 else
278 }
280 /* Do any processing required when DECL (a member template
281 declaration) is finished. Returns the TEMPLATE_DECL corresponding
282 to DECL, unless it is a specialization, in which case the DECL
283 itself is returned. */
285 tree
287 {
294 {
295 tree type;
303 {
307 }
309 }
314 {
316 {
319 }
320 else
322 }
323 else
328 }
330 /* Create a template info node. */
332 tree
334 {
339 }
341 /* DECL_TEMPLATE_INFO, if applicable, or NULL_TREE. */
343 static tree
345 {
346 /* This needs to match template_info_decl_check. */
349 {
363 }
365 }
367 /* Return the template info node corresponding to T, whatever T is. */
369 tree
371 {
393 }
395 /* Returns the template nesting level of the indicated class TYPE.
397 For example, in:
398 template <class T>
399 struct A
400 {
401 template <class U>
402 struct B {};
403 };
405 A<T>::B<U> has depth two, while A<T> has depth one.
406 Both A<T>::B<int> and A<int>::B<U> have depth one, if
407 they are instantiations, not specializations.
409 This function is guaranteed to return 0 if passed NULL_TREE so
410 that, for example, `template_class_depth (current_class_type)' is
411 always safe. */
413 int
415 {
419 {
429 {
432 else
434 }
437 else
439 }
442 }
444 /* Return TRUE if NODE instantiates a template that has arguments of
445 its own, be it directly a primary template or indirectly through a
446 partial specializations. */
447 static bool
449 {
461 /* So now we know we have a specialization, but it could be a full
462 or a partial specialization. To tell which, compare the depth of
463 its template arguments with those of its context. */
472 }
474 /* Subroutine of maybe_begin_member_template_processing.
475 Returns true if processing DECL needs us to push template parms. */
477 static bool
479 {
485 }
487 /* Subroutine of maybe_begin_member_template_processing.
488 Push the template parms in PARMS, starting from LEVELS steps into the
489 chain, and ending at the beginning, since template parms are listed
490 innermost first. */
492 static void
494 {
502 current_template_parms
510 NULL);
512 {
521 {
528 /* Push the CONST_DECL. */
534 }
535 }
536 }
538 /* Restore the template parameter context for a member template, a
539 friend template defined in a class definition, or a non-template
540 member of template class. */
542 void
544 {
545 tree parms;
550 {
553 /* Disregard full specializations (c++/60999). */
556 }
559 {
564 {
567 }
570 }
572 /* Remember how many levels of template parameters we pushed so that
573 we can pop them later. */
575 }
577 /* Undo the effects of maybe_begin_member_template_processing. */
579 void
581 {
590 {
594 }
595 }
597 /* Return a new template argument vector which contains all of ARGS,
598 but has as its innermost set of arguments the EXTRA_ARGS. */
600 tree
602 {
603 tree new_args;
621 }
623 /* Like add_to_template_args, but only the outermost ARGS are added to
624 the EXTRA_ARGS. In particular, all but TMPL_ARGS_DEPTH
625 (EXTRA_ARGS) levels are added. This function is used to combine
626 the template arguments from a partial instantiation with the
627 template arguments used to attain the full instantiation from the
628 partial instantiation.
630 If ARGS is a TEMPLATE_DECL, use its parameters as args. */
632 tree
634 {
635 tree new_args;
640 {
643 }
645 /* If there are more levels of EXTRA_ARGS than there are ARGS,
646 something very fishy is going on. */
649 /* If *all* the new arguments will be the EXTRA_ARGS, just return
650 them. */
654 /* For the moment, we make ARGS look like it contains fewer levels. */
659 /* Now, we restore ARGS to its full dimensions. */
663 }
665 /* Return the N levels of innermost template arguments from the ARGS. */
667 tree
669 {
670 tree new_args;
676 /* If N is 1, just return the innermost set of template arguments. */
680 /* If we're not removing anything, just return the arguments we were
681 given. */
687 /* Make a new set of arguments, not containing the outer arguments. */
694 }
696 /* The inverse of get_innermost_template_args: Return all but the innermost
697 EXTRA_LEVELS levels of template arguments from the ARGS. */
699 static tree
701 {
702 tree new_args;
708 /* If N is 1, just return the outermost set of template arguments. */
712 /* If we're not removing anything, just return the arguments we were
713 given. */
718 /* Make a new set of arguments, not containing the inner arguments. */
725 }
727 /* We've got a template header coming up; push to a new level for storing
728 the parms. */
730 void
732 {
733 /* We use a non-tag-transparent scope here, which causes pushtag to
734 put tags in this scope, rather than in the enclosing class or
735 namespace scope. This is the right thing, since we want
736 TEMPLATE_DECLS, and not TYPE_DECLS for template classes. For a
737 global template class, push_template_decl handles putting the
738 TEMPLATE_DECL into top-level scope. For a nested template class,
739 e.g.:
741 template <class T> struct S1 {
742 template <class T> struct S2 {};
743 };
745 pushtag contains special code to insert the TEMPLATE_DECL for S2
746 at the right scope. */
752 /* Add a dummy parameter level while we process the parameter list. */
753 current_template_parms
756 current_template_parms);
757 }
759 /* This routine is called when a specialization is declared. If it is
760 invalid to declare a specialization here, an error is reported and
761 false is returned, otherwise this routine will return true. */
763 static bool
765 {
768 /* [temp.expl.spec]
770 An explicit specialization shall be declared in the namespace of
771 which the template is a member, or, for member templates, in the
772 namespace of which the enclosing class or enclosing class
773 template is a member. An explicit specialization of a member
774 function, member class or static data member of a class template
775 shall be declared in the namespace of which the class template
776 is a member. */
778 {
781 }
783 /* [temp.expl.spec]
785 In an explicit specialization declaration for a member of a class
786 template or a member template that appears in namespace scope,
787 the member template and some of its enclosing class templates may
788 remain unspecialized, except that the declaration shall not
789 explicitly specialize a class member template if its enclosing
790 class templates are not explicitly specialized as well. */
792 {
795 }
798 }
800 /* We've just seen template <>. */
802 bool
804 {
808 }
810 /* Called at then end of processing a declaration preceded by
811 template<>. */
813 void
815 {
818 }
820 /* Any template <>'s that we have seen thus far are not referring to a
821 function specialization. */
823 void
825 {
828 }
830 /* We've just seen a template header. If SPECIALIZATION is nonzero,
831 it was of the form template <>. */
833 static void
835 {
837 template_header_count++;
838 }
840 /* We're beginning an explicit instantiation. */
842 void
844 {
847 }
850 void
852 {
855 }
857 /* An explicit specialization or partial specialization of TMPL is being
858 declared. Check that the namespace in which the specialization is
859 occurring is permissible. Returns false iff it is invalid to
860 specialize TMPL in the current namespace. */
862 static bool
864 {
867 /* [tmpl.expl.spec]
869 An explicit specialization shall be declared in a namespace enclosing the
870 specialized template. An explicit specialization whose declarator-id is
871 not qualified shall be declared in the nearest enclosing namespace of the
872 template, or, if the namespace is inline (7.3.1), any namespace from its
873 enclosing namespace set. */
876 {
879 }
882 /* Same or enclosing namespace. */
884 else
885 {
886 auto_diagnostic_group d;
892 }
893 }
895 /* SPEC is an explicit instantiation. Check that it is valid to
896 perform this explicit instantiation in the current namespace. */
898 static void
900 {
901 tree ns;
903 /* DR 275: An explicit instantiation shall appear in an enclosing
904 namespace of its template. */
910 }
912 /* Returns true if TYPE is a new partial specialization that needs to be
913 set up. This may also modify TYPE to point to the correct (new or
914 existing) constrained partial specialization. */
916 static bool
918 {
919 /* An implicit instantiation of an incomplete type implies
920 the definition of a new class template.
922 template<typename T>
923 struct S;
925 template<typename T>
926 struct S<T*>;
928 Here, S<T*> is an implicit instantiation of S whose type
929 is incomplete. */
933 /* It can also be the case that TYPE is a completed specialization.
934 Continuing the previous example, suppose we also declare:
936 template<typename T>
937 requires Integral<T>
938 struct S<T*>;
940 Here, S<T*> refers to the specialization S<T*> defined
941 above. However, we need to differentiate definitions because
942 we intend to define a new partial specialization. In this case,
943 we rely on the fact that the constraints are different for
944 this declaration than that above.
946 Note that we also get here for injected class names and
947 late-parsed template definitions. We must ensure that we
948 do not create new type declarations for those cases. */
950 {
954 /* If there are no template parameters, this cannot be a new
955 partial template specialization? */
959 /* The injected-class-name is not a new partial specialization. */
963 /* If the constraints are not the same as those of the primary
964 then, we can probably create a new specialization. */
968 {
972 }
974 /* Also, if there's a pre-existing specialization with matching
975 constraints, then this also isn't new. */
978 {
984 {
987 }
989 }
991 /* Create a new type node (and corresponding type decl)
992 for the newly declared specialization. */
998 /* We only need a separate type node for storing the definition of this
999 partial specialization; uses of S<T*> are unconstrained, so all are
1000 equivalent. So keep TYPE_CANONICAL the same. */
1003 /* Build the corresponding type decl. */
1014 }
1017 }
1019 /* The TYPE is being declared. If it is a template type, that means it
1020 is a partial specialization. Do appropriate error-checking. */
1022 tree
1024 {
1025 tree context;
1030 /* A lambda that appears in specialization context is not itself a
1031 specialization. */
1035 /* An injected-class-name is not a specialization. */
1040 {
1044 }
1049 {
1055 else
1058 }
1060 {
1061 /* This is for ordinary explicit specialization and partial
1062 specialization of a template class such as:
1064 template <> class C<int>;
1066 or:
1068 template <class T> class C<T*>;
1070 Make sure that `C<int>' and `C<T*>' are implicit instantiations. */
1073 {
1080 {
1085 }
1086 }
1092 /* Trying to define a specialization either without a template<> header
1093 or in an inappropriate place. We've already given an error, so just
1094 bail now so we don't actually define the specialization. */
1096 }
1102 {
1103 /* This is for an explicit specialization of member class
1104 template according to [temp.expl.spec/18]:
1106 template <> template <class U> class C<int>::D;
1108 The context `C<int>' must be an implicit instantiation.
1109 Otherwise this is just a member class template declared
1110 earlier like:
1112 template <> class C<int> { template <class U> class D; };
1113 template <> template <class U> class C<int>::D;
1115 In the first case, `C<int>::D' is a specialization of `C<T>::D'
1116 while in the second case, `C<int>::D' is a primary template
1117 and `C<T>::D' may not exist. */
1121 {
1122 tree t;
1127 {
1128 auto_diagnostic_group d;
1131 type))
1134 }
1136 /* Check for invalid specialization after instantiation:
1138 template <> template <> class C<int>::D<int>;
1139 template <> template <class U> class C<int>::D; */
1143 {
1147 {
1148 /* We already have a full specialization of this partial
1149 instantiation, or a full specialization has been
1150 looked up but not instantiated. Reassign it to the
1151 new member specialization template. */
1152 spec_entry elt;
1166 spec_entry **slot
1171 }
1172 else
1173 /* But if we've had an implicit instantiation, that's a
1174 problem ([temp.expl.spec]/6). */
1177 }
1179 /* Make sure that the specialization is valid. */
1184 /* Mark TYPE as a specialization. And as a result, we only
1185 have one level of template argument for the innermost
1186 class template. */
1191 }
1192 }
1194 {
1195 /* Someday C++0x may allow for enum template specialization. */
1200 else
1201 {
1204 }
1205 }
1208 }
1210 /* Make sure ARGS doesn't use any inappropriate typedefs; we should have
1211 gone through coerce_template_parms by now. */
1213 static void
1215 {
1217 {
1226 /* Allow typedefs on the type of a non-type argument, since a
1228 else
1230 }
1231 }
1233 static void
1235 {
1240 }
1242 /* Retrieve the specialization (in the sense of [temp.spec] - a
1243 specialization is either an instantiation or an explicit
1244 specialization) of TMPL for the given template ARGS. If there is
1245 no such specialization, return NULL_TREE. The ARGS are a vector of
1246 arguments, or a vector of vectors of arguments, in the case of
1247 templates with more than one level of parameters.
1249 If TMPL is a type template and CLASS_SPECIALIZATIONS_P is true,
1250 then we search for a partial specialization matching ARGS. This
1251 parameter is ignored if TMPL is not a class template.
1253 We can also look up a FIELD_DECL, if it is a lambda capture pack; the
1254 result is a NONTYPE_ARGUMENT_PACK. */
1256 static tree
1258 {
1268 /* There should be as many levels of arguments as there are
1269 levels of parameters. */
1278 /* Lambda functions in templates aren't instantiated normally, but through
1279 tsubst_lambda_expr. */
1283 spec_entry elt;
1291 else
1298 }
1300 /* Like retrieve_specialization, but for local declarations. */
1302 tree
1304 {
1310 }
1312 /* Returns nonzero iff DECL is a specialization of TMPL. */
1314 int
1316 {
1317 tree t;
1320 {
1326 }
1327 else
1328 {
1337 }
1340 }
1342 /* Returns nonzero iff DECL is a specialization of friend declaration
1343 FRIEND_DECL according to [temp.friend]. */
1345 bool
1347 {
1354 /* For [temp.friend/6] when FRIEND_DECL is an ordinary member function
1355 of a template class, we want to check if DECL is a specialization
1356 if this. */
1361 {
1362 /* We want a TEMPLATE_DECL for `is_specialization_of'. */
1365 }
1370 /* There is nothing to do if this is not a template friend. */
1377 /* [temp.friend/6]
1378 A member of a class template may be declared to be a friend of a
1379 non-template class. In this case, the corresponding member of
1380 every specialization of the class template is a friend of the
1381 class granting friendship.
1383 For example, given a template friend declaration
1385 template <class T> friend void A<T>::f();
1387 the member function below is considered a friend
1389 template <> struct A<int> {
1390 void f();
1391 };
1393 For this type of template friend, TEMPLATE_DEPTH below will be
1394 nonzero. To determine if DECL is a friend of FRIEND, we first
1395 check if the enclosing class is a specialization of another. */
1402 {
1403 /* Next, we check the members themselves. In order to handle
1404 a few tricky cases, such as when FRIEND_DECL's are
1406 template <class T> friend void A<T>::g(T t);
1407 template <class T> template <T t> friend void A<T>::h();
1409 and DECL's are
1411 void A<int>::g(int);
1412 template <int> void A<int>::h();
1414 we need to figure out ARGS, the template arguments from
1415 the context of DECL. This is required for template substitution
1416 of `T' in the function parameter of `g' and template parameter
1417 of `h' in the above examples. Here ARGS corresponds to `int'. */
1424 {
1426 {
1429 else
1431 current_depth++;
1432 }
1434 }
1437 {
1439 tree friend_type;
1440 tree decl_type;
1441 tree friend_args_type;
1442 tree decl_args_type;
1444 /* Make sure that both DECL and FRIEND_DECL are templates or
1445 non-templates. */
1451 {
1452 /* If both are templates, check template parameter list. */
1453 tree friend_parms
1458 friend_parms))
1462 }
1463 else
1471 /* Check if return types match. */
1475 /* Check if function parameter types match, ignoring the
1476 `this' parameter. */
1485 }
1486 else
1487 {
1488 /* DECL is a TYPE_DECL */
1492 /* Make sure that both DECL and FRIEND_DECL are templates or
1493 non-templates. */
1494 is_template
1501 {
1502 tree friend_parms;
1503 /* If both are templates, check the name of the two
1504 TEMPLATE_DECL's first because is_friend didn't. */
1509 /* Now check template parameter list. */
1510 friend_parms
1513 return comp_template_parms
1515 friend_parms);
1516 }
1517 else
1520 }
1521 }
1523 }
1525 /* Register the specialization SPEC as a specialization of TMPL with
1526 the indicated ARGS. IS_FRIEND indicates whether the specialization
1527 is actually just a friend declaration. ATTRLIST is the list of
1528 attributes that the specialization is declared with or NULL when
1529 it isn't. Returns SPEC, or an equivalent prior declaration, if
1530 available.
1532 We also store instantiations of field packs in the hash table, even
1533 though they are not themselves templates, to make lookup easier. */
1535 static tree
1537 hashval_t hash)
1538 {
1539 tree fn;
1545 spec_entry elt;
1556 else
1559 /* We can sometimes try to re-register a specialization that we've
1560 already got. In particular, regenerate_decl_from_template calls
1561 duplicate_decls which will update the specialization list. But,
1562 we'll still get called again here anyhow. It's more convenient
1563 to simply allow this than to try to prevent it. */
1567 {
1569 {
1572 {
1574 fn);
1576 }
1577 else
1578 {
1579 tree clone;
1580 /* This situation should occur only if the first
1581 specialization is an implicit instantiation, the
1582 second is an explicit specialization, and the
1583 implicit instantiation has not yet been used. That
1584 situation can occur if we have implicitly
1585 instantiated a member function and then specialized
1586 it later.
1588 We can also wind up here if a friend declaration that
1589 looked like an instantiation turns out to be a
1590 specialization:
1592 template <class T> void foo(T);
1593 class S { friend void foo<>(int) };
1594 template <> void foo(int);
1596 We transform the existing DECL in place so that any
1597 pointers to it become pointers to the updated
1598 declaration.
1600 If there was a definition for the template, but not
1601 for the specialization, we want this to look as if
1602 there were no definition, and vice versa. */
1606 /* The call to duplicate_decls will have applied
1607 [temp.expl.spec]:
1609 An explicit specialization of a function template
1610 is inline only if it is explicitly declared to be,
1611 and independently of whether its function template
1612 is.
1614 to the primary function; now copy the inline bits to
1615 the various clones. */
1617 {
1624 }
1628 }
1629 }
1631 {
1634 /* We've already complained in duplicate_decls. */
1638 /* Dup decl failed, but this is a new definition. Set the
1639 line number so any errors match this new
1640 definition. */
1644 }
1645 }
1649 /* A specialization must be declared in the same namespace as the
1650 template it is specializing. */
1663 /* If TMPL is a forward declaration of a template function, keep a list
1664 of all specializations in case we need to reassign them to a friend
1665 template later in tsubst_friend_function.
1667 Also keep a list of all variable template instantiations so that
1668 process_partial_specialization can check whether a later partial
1669 specialization would have used it. */
1674 }
1676 /* Restricts tree and type comparisons. */
1680 /* Whether we are comparing template arguments during partial ordering
1681 (and therefore want the comparison to look through dependent alias
1682 template specializations). */
1686 /* Returns true iff two spec_entry nodes are equivalent. */
1688 bool
1690 {
1699 /* tmpl could be a FIELD_DECL for a capture pack. */
1703 {
1704 /* Partial specializations of a variable template can be distinguished by
1705 constraints. */
1709 }
1715 }
1717 /* Returns a hash for a template TMPL and template arguments ARGS. */
1719 static hashval_t
1721 {
1724 }
1726 hashval_t
1728 {
1733 }
1735 /* Returns a hash for a spec_entry node based on the TMPL and ARGS members,
1736 ignoring SPEC. */
1738 hashval_t
1740 {
1744 }
1746 /* Recursively calculate a hash value for a template argument ARG, for use
1747 in the hash tables of template specializations. We must be
1748 careful to (at least) skip the same entities template_args_equal
1749 does. */
1751 hashval_t
1753 {
1758 /* Strip nop-like things, but not the same as STRIP_NOPS. */
1769 {
1771 /* Getting here with an ARGUMENT_PACK_SELECT means we're probably
1772 preserving it in a hash table, which is bad because it will change
1773 meaning when gen_elem_of_pack_expansion_instantiation changes the
1774 ARGUMENT_PACK_SELECT_INDEX. */
1808 {
1811 {
1814 }
1816 }
1820 {
1823 }
1839 val = iterative_hash_template_arg
1851 val);
1853 val);
1862 /* [temp.over.link] Two lambda-expressions are never considered
1863 equivalent.
1865 So just hash the closure type. */
1876 /* Now hash operands as usual. */
1880 {
1883 {
1887 }
1889 call_expr_arg_iterator ai;
1894 }
1898 }
1902 {
1905 {
1906 // We want an alias specialization that survived strip_typedefs
1907 // to hash differently from its TYPE_CANONICAL, to avoid hash
1908 // collisions that compare as different in template_args_equal.
1909 // These could be dependent specializations that strip_typedefs
1910 // left alone, or untouched specializations because
1911 // coerce_template_parms returns the unconverted template
1912 // arguments if it sees incomplete argument packs.
1915 }
1918 {
1925 {
1926 /* Hash the components that are relevant to TYPENAME_TYPE
1927 equivalence as determined by structural_comptypes. We
1928 can only coherently do this when comparing_specializations
1929 is set, because otherwise structural_comptypes tries
1930 resolving TYPENAME_TYPE via the current instantiation. */
1935 }
1942 {
1945 }
1947 }
1960 }
1961 }
1963 /* Unregister the specialization SPEC as a specialization of TMPL.
1964 Replace it with NEW_SPEC, if NEW_SPEC is non-NULL. Returns true
1965 if the SPEC was listed as a specialization of TMPL.
1967 Note that SPEC has been ggc_freed, so we can't look inside it. */
1969 bool
1971 {
1973 spec_entry elt;
1980 {
1985 }
1988 }
1990 /* Like register_specialization, but for local declarations. We are
1991 registering SPEC, an instantiation of TMPL. */
1993 void
1995 {
1998 }
2000 /* Registers T as a specialization of itself. This is used to preserve
2001 the references to already-parsed parameters when instantiating
2002 postconditions. */
2004 void
2006 {
2008 }
2010 /* TYPE is a class type. Returns true if TYPE is an explicitly
2011 specialized class. */
2013 bool
2015 {
2019 }
2021 /* Print the list of functions at FNS, going through all the overloads
2022 for each element of the list. Alternatively, FNS cannot be a
2023 TREE_LIST, in which case it will be printed together with all the
2024 overloads.
2026 MORE and *STR should respectively be FALSE and NULL when the function
2027 is called from the outside. They are used internally on recursive
2028 calls. print_candidates manages the two parameters and leaves NULL
2029 in *STR when it ends. */
2031 static void
2033 {
2037 else
2039 {
2045 {
2048 else
2051 }
2053 }
2054 }
2056 /* Print the list of candidate FNS in an error message. FNS can also
2057 be a TREE_LIST of non-functions in the case of an ambiguous lookup. */
2059 void
2061 {
2065 }
2067 /* Get a (possibly) constrained template declaration for the
2068 purpose of ordering candidates. */
2069 static tree
2071 {
2075 /* Also handle a list from resolve_address_of_overloaded_function with the
2076 function in TREE_PURPOSE. */
2081 }
2083 /* Among candidates having the same signature, return the
2084 most constrained or NULL_TREE if there is no best candidate.
2085 If the signatures of candidates vary (e.g., template
2086 specialization vs. member function), then there can be no
2087 most constrained.
2089 Note that we don't compare constraints on the functions
2090 themselves, but rather those of their templates. */
2091 tree
2093 {
2094 // Try to find the best candidate in a first pass.
2097 {
2104 }
2106 // Verify that the champ is better than previous candidates.
2111 }
2114 }
2117 /* Returns the template (one of the functions given by TEMPLATE_ID)
2118 which can be specialized to match the indicated DECL with the
2119 explicit template args given in TEMPLATE_ID. The DECL may be
2120 NULL_TREE if none is available. In that case, the functions in
2121 TEMPLATE_ID are non-members.
2123 If NEED_MEMBER_TEMPLATE is nonzero the function is known to be a
2124 specialization of a member template.
2126 The TEMPLATE_COUNT is the number of references to qualifying
2127 template classes that appeared in the name of the function. See
2128 check_explicit_specialization for a more accurate description.
2130 TSK indicates what kind of template declaration (if any) is being
2131 declared. TSK_TEMPLATE indicates that the declaration given by
2132 DECL, though a FUNCTION_DECL, has template parameters, and is
2133 therefore a template function.
2135 The template args (those explicitly specified and those deduced)
2136 are output in a newly created vector *TARGS_OUT.
2138 If it is impossible to determine the result, an error message is
2139 issued. The error_mark_node is returned to indicate failure. */
2141 static tree
2143 tree decl,
2147 tmpl_spec_kind tsk)
2148 {
2149 tree fns;
2150 tree targs;
2151 tree explicit_targs;
2154 /* A TREE_LIST of templates of which DECL may be a specialization.
2155 The TREE_VALUE of each node is a TEMPLATE_DECL. The
2156 corresponding TREE_PURPOSE is the set of template arguments that,
2157 when used to instantiate the template, would produce a function
2158 with the signature of DECL. */
2168 /* We shouldn't be specializing a member template of an
2169 unspecialized class template; we already gave an error in
2170 check_specialization_scope, now avoid crashing. */
2174 {
2177 }
2185 /* Check for baselinks. */
2190 {
2194 }
2196 {
2199 }
2201 /* Count the number of template headers specified for this
2202 specialization. */
2213 {
2216 tf_warning_or_error);
2220 }
2222 {
2226 {
2227 tree decl_arg_types;
2228 tree fn_arg_types;
2230 /* In case of explicit specialization, we need to check if
2231 the number of template headers appearing in the specialization
2232 is correct. This is usually done in check_explicit_specialization,
2233 but the check done there cannot be exhaustive when specializing
2234 member functions. Consider the following code:
2236 template <> void A<int>::f(int);
2237 template <> template <> void A<int>::f(int);
2239 Assuming that A<int> is not itself an explicit specialization
2240 already, the first line specializes "f" which is a non-template
2241 member function, whilst the second line specializes "f" which
2242 is a template member function. So both lines are syntactically
2243 correct, and check_explicit_specialization does not reject
2244 them.
2246 Here, we can do better, as we are matching the specialization
2247 against the declarations. We count the number of template
2248 headers, and we check if they match TEMPLATE_COUNT + 1
2249 (TEMPLATE_COUNT is the number of qualifying template classes,
2250 plus there must be another header for the member template
2251 itself).
2253 Notice that if header_count is zero, this is not a
2254 specialization but rather a template instantiation, so there
2255 is no check we can perform here. */
2257 {
2260 }
2262 /* Check that the number of template arguments at the
2263 innermost level for DECL is the same as for FN. */
2271 /* DECL might be a specialization of FN. */
2275 /* For a non-static member function, we need to make sure
2276 that the const qualification is the same. Since
2277 get_bindings does not try to merge the "this" parameter,
2278 we must do the comparison explicitly. */
2280 {
2285 /* And the ref-qualification. */
2289 }
2291 /* Skip the "this" parameter and, for constructors of
2292 classes with virtual bases, the VTT parameter. A
2293 full specialization of a constructor will have a VTT
2294 parameter, but a template never will. */
2295 decl_arg_types
2297 fn_arg_types
2300 /* Function templates cannot be specializations; there are
2301 no partial specializations of functions. Therefore, if
2302 the type of DECL does not match FN, there is no
2303 match.
2305 Note that it should never be the case that we have both
2306 candidates added here, and for regular member functions
2307 below. */
2309 {
2311 current_template_parms))
2324 {
2325 /* C++20 CA104: Substitute directly into the
2326 constraint-expression. */
2332 }
2336 }
2338 /* See whether this function might be a specialization of this
2339 template. Suppress access control because we might be trying
2340 to make this specialization a friend, and we have already done
2341 access control for the declaration of the specialization. */
2347 /* We cannot deduce template arguments that when used to
2348 specialize TMPL will produce DECL. */
2352 /* We deduced something involving 'auto', which isn't a valid
2353 template argument. */
2356 /* Save this template, and the arguments deduced. */
2358 }
2360 /* FN is an ordinary member function, and we need a
2361 specialization of a member template. */
2362 ;
2364 /* We can get IDENTIFIER_NODEs here in certain erroneous
2365 cases. */
2366 ;
2368 /* This is just an ordinary non-member function. Nothing can
2369 be a specialization of that. */
2370 ;
2372 /* Cannot specialize functions that are created implicitly. */
2373 ;
2374 else
2375 {
2376 tree decl_arg_types;
2378 /* This is an ordinary member function. However, since
2379 we're here, we can assume its enclosing class is a
2380 template class. For example,
2382 template <typename T> struct S { void f(); };
2383 template <> void S<int>::f() {}
2385 Here, S<int>::f is a non-template, but S<int> is a
2386 template class. If FN has the same type as DECL, we
2387 might be in business. */
2390 /* Its enclosing class is an explicit specialization
2391 of a template class. This is not a candidate. */
2396 /* The return types differ. */
2399 /* Adjust the type of DECL in case FN is a static member. */
2406 decl_arg_types))
2414 // If the deduced arguments do not satisfy the constraints,
2415 // this is not a candidate.
2419 // Add the candidate.
2421 }
2422 }
2425 {
2426 /* We have:
2428 [temp.expl.spec]
2430 It is possible for a specialization with a given function
2431 signature to be instantiated from more than one function
2432 template. In such cases, explicit specification of the
2433 template arguments must be used to uniquely identify the
2434 function template specialization being specialized.
2436 Note that here, there's no suggestion that we're supposed to
2437 determine which of the candidate templates is most
2438 specialized. However, we, also have:
2440 [temp.func.order]
2442 Partial ordering of overloaded function template
2443 declarations is used in the following contexts to select
2444 the function template to which a function template
2445 specialization refers:
2447 -- when an explicit specialization refers to a function
2448 template.
2450 So, we do use the partial ordering rules, at least for now.
2451 This extension can only serve to make invalid programs valid,
2452 so it's safe. And, there is strong anecdotal evidence that
2453 the committee intended the partial ordering rules to apply;
2454 the EDG front end has that behavior, and John Spicer claims
2455 that the committee simply forgot to delete the wording in
2456 [temp.expl.spec]. */
2459 {
2462 }
2463 }
2465 // Concepts allows multiple declarations of member functions
2466 // with the same signature. Like above, we need to rely on
2467 // on the partial ordering of those candidates to determine which
2468 // is the best.
2470 {
2472 {
2475 }
2476 }
2479 {
2480 auto_diagnostic_group d;
2485 "saw %d %<template<>%>, need %d for "
2490 }
2494 {
2495 auto_diagnostic_group d;
2501 }
2503 /* We have one, and exactly one, match. */
2505 {
2509 /* Propagate the candidate's constraints to the declaration. */
2513 /* DECL is a re-declaration or partial instantiation of a template
2514 function. */
2517 /* It was a specialization of an ordinary member function in a
2518 template class. */
2520 }
2522 /* It was a specialization of a template. */
2526 /* Propagate the template's constraints to the declaration. */
2531 }
2533 /* Returns a chain of parameter types, exactly like the SPEC_TYPES,
2534 but with the default argument values filled in from those in the
2535 TMPL_TYPES. */
2537 static tree
2539 tree tmpl_types)
2540 {
2541 tree new_spec_types;
2549 /* Substitute into the rest of the list. */
2550 new_spec_types =
2554 /* Add the default argument for this parameter. */
2557 new_spec_types);
2558 }
2560 /* DECL is an explicit specialization. Replicate default arguments
2561 from the template it specializes. (That way, code like:
2563 template <class T> void f(T = 3);
2564 template <> void f(double);
2565 void g () { f (); }
2567 works, as required.) An alternative approach would be to look up
2568 the correct default arguments at the call-site, but this approach
2569 is consistent with how implicit instantiations are handled. */
2571 static void
2573 {
2574 tree tmpl;
2575 tree spec_types;
2576 tree tmpl_types;
2577 tree new_spec_types;
2578 tree old_type;
2579 tree new_type;
2580 tree t;
2585 /* See if there's anything we need to do. */
2598 {
2599 /* Remove the this pointer, but remember the object's type for
2600 CV quals. */
2606 {
2607 /* DECL may contain more parameters than TMPL due to the extra
2608 in-charge parameter in constructors and destructors. */
2611 }
2613 {
2616 }
2617 }
2619 /* Compute the merged default arguments. */
2620 new_spec_types =
2623 /* Compute the new FUNCTION_TYPE. */
2625 {
2629 new_spec_types);
2632 /* Put the in-charge parameter back. */
2635 new_spec_types);
2639 new_spec_types);
2640 }
2641 else
2643 new_spec_types);
2649 }
2651 /* Return the number of template headers we expect to see for a definition
2652 or specialization of CTYPE or one of its non-template members. */
2654 int
2656 {
2660 {
2661 /* You're supposed to have one `template <...>' for every
2662 template class, but you don't need one for a full
2663 specialization. For example:
2665 template <class T> struct S{};
2666 template <> struct S<int> { void f(); };
2667 void S<int>::f () {}
2669 is correct; there shouldn't be a `template <>' for the
2670 definition of `S<int>::f'. */
2672 /* If CTYPE does not have template information of any
2673 kind, then it is not a template, nor is it nested
2674 within a template. */
2682 }
2685 }
2687 /* Do a simple sanity check on the template headers that precede the
2688 variable declaration DECL. */
2690 void
2692 {
2697 {
2700 "variable templates only available with "
2703 // Namespace-scope variable templates should have a template header.
2705 }
2707 {
2708 auto_diagnostic_group d;
2710 "too many template headers for %qD "
2716 "members of an explicitly specialized class are defined "
2718 }
2719 }
2721 /* An explicit specialization whose declarator-id or class-head-name is not
2722 qualified shall be declared in the nearest enclosing namespace of the
2723 template, or, if the namespace is inline (7.3.1), any namespace from its
2724 enclosing namespace set.
2726 If the name declared in the explicit instantiation is an unqualified name,
2727 the explicit instantiation shall appear in the namespace where its template
2728 is declared or, if that namespace is inline (7.3.1), any namespace from its
2729 enclosing namespace set. */
2731 void
2733 {
2738 {
2744 /* This was allowed in C++98, so only pedwarn. */
2746 "outside its namespace must use a nested-name-"
2748 }
2749 }
2751 /* Warn for a template specialization SPEC that is missing some of a set
2752 of function or type attributes that the template TEMPL is declared with.
2753 ATTRLIST is a list of additional attributes that SPEC should be taken
2754 to ultimately be declared with. */
2756 static void
2758 {
2762 /* Avoid warning if the difference between the primary and
2763 the specialization is not in one of the attributes below. */
2767 };
2769 /* Put together a list of the black listed attributes that the primary
2770 template is declared with that the specialization is not, in case
2771 it's not apparent from the most recent declaration of the primary. */
2779 auto_diagnostic_group d;
2782 spec))
2783 {
2790 }
2791 }
2793 /* Check to see if the function just declared, as indicated in
2794 DECLARATOR, and in DECL, is a specialization of a function
2795 template. We may also discover that the declaration is an explicit
2796 instantiation at this point.
2798 Returns DECL, or an equivalent declaration that should be used
2799 instead if all goes well. Issues an error message if something is
2800 amiss. Returns error_mark_node if the error is not easily
2801 recoverable.
2803 FLAGS is a bitmask consisting of the following flags:
2805 2: The function has a definition.
2806 4: The function is a friend.
2808 The TEMPLATE_COUNT is the number of references to qualifying
2809 template classes that appeared in the name of the function. For
2810 example, in
2812 template <class T> struct S { void f(); };
2813 void S<int>::f();
2815 the TEMPLATE_COUNT would be 1. However, explicitly specialized
2816 classes are not counted in the TEMPLATE_COUNT, so that in
2818 template <class T> struct S {};
2819 template <> struct S<int> { void f(); }
2820 template <> void S<int>::f();
2822 the TEMPLATE_COUNT would be 0. (Note that this declaration is
2823 invalid; there should be no template <>.)
2825 If the function is a specialization, it is marked as such via
2826 DECL_TEMPLATE_SPECIALIZATION. Furthermore, its DECL_TEMPLATE_INFO
2827 is set up correctly, and it is added to the list of specializations
2828 for that template. */
2830 tree
2832 tree decl,
2835 tree attrlist)
2836 {
2845 tmpl_spec_kind tsk;
2848 {
2851 else
2853 }
2854 else
2858 {
2861 {
2864 }
2868 {
2870 /* This could be something like:
2872 template <class T> void f(T);
2873 class S { friend void f<>(int); } */
2875 else
2876 {
2877 /* This case handles bogus declarations like template <>
2878 template <class T> void f<int>(); */
2882 declarator);
2884 }
2885 }
2889 /* The error has already been reported in
2890 check_specialization_scope. */
2896 /* Fall through. */
2909 decl);
2912 else
2916 /* Fall through. */
2922 /* In cases like template<> constexpr bool v = true;
2923 We'll give an error in check_template_variable. */
2929 else
2935 {
2936 /* This case handles bogus declarations like template <>
2937 template <class T> void f<int>(); */
2942 declarator);
2944 {
2945 /* Partial specialization of variable template. */
2949 }
2952 "non-type partial specialization %qE "
2954 else
2956 "non-class, non-variable partial specialization %qE "
2959 ok:;
2960 }
2963 /* This is a specialization of a member template, without
2964 specialization the containing class. Something like:
2966 template <class T> struct S {
2967 template <class U> void f (U);
2968 };
2969 template <> template <class U> void S<int>::f(U) {}
2971 That's a specialization -- but of the entire template. */
2977 }
2980 /* This doesn't apply to variable templates. */
2982 {
2986 {
2990 }
2991 }
2994 {
3000 /* Make sure that the declarator is a TEMPLATE_ID_EXPR. */
3002 {
3003 tree fns;
3008 else
3009 {
3010 /* If there is no class context, the explicit instantiation
3011 must be at namespace scope. */
3014 /* Find the namespace binding, using the declaration
3015 context. */
3019 {
3020 /* If lookup fails, look for a friend declaration so we can
3021 give a better diagnostic. */
3022 fns = (lookup_qualified_name
3027 }
3030 {
3033 }
3034 }
3037 }
3043 {
3045 /* A specialization in class scope. This is invalid,
3046 but the error will already have been flagged by
3047 check_specialization_scope. */
3049 else
3050 {
3051 /* It's not valid to write an explicit instantiation in
3052 class scope, e.g.:
3054 class C { template void f(); }
3056 This case is caught by the parser. However, on
3057 something like:
3059 template class C { void f(); };
3061 (which is invalid) we can get here. The error will be
3062 issued later. */
3063 ;
3064 }
3067 }
3070 {
3071 // We'll match variable templates in start_decl.
3075 /* Find the list of functions in ctype that have the same
3076 name as the declared function. */
3080 {
3084 {
3085 /* From [temp.expl.spec]:
3087 If such an explicit specialization for the member
3088 of a class template names an implicitly-declared
3089 special member function (clause _special_), the
3090 program is ill-formed.
3092 Similar language is found in [temp.explicit]. */
3095 }
3098 }
3100 /* For a type-conversion operator, We might be looking for
3101 `operator int' which will be a specialization of
3102 `operator T'. Grab all the conversion operators, and
3103 then select from them. */
3108 {
3111 }
3112 else
3114 }
3116 /* Figure out what exactly is being specialized at this point.
3117 Note that for an explicit instantiation, even one for a
3118 member function, we cannot tell a priori whether the
3119 instantiation is for a member template, or just a member
3120 function of a template class. Even if a member template is
3121 being instantiated, the member template arguments may be
3122 elided if they can be deduced from the rest of the
3123 declaration. */
3126 member_specialization,
3127 template_count,
3128 tsk);
3131 /* We couldn't figure out what this declaration was
3132 specializing. */
3134 else
3135 {
3137 {
3138 auto_diagnostic_group d;
3140 "friend declaration %qD is not visible to "
3144 }
3153 {
3154 /* We don't set DECL_EXPLICIT_INSTANTIATION here; that
3155 is done by do_decl_instantiation later. */
3161 {
3162 /* If TMPL is not the most general template (for
3163 example, if TMPL is a friend template that is
3164 injected into namespace scope), then there will
3165 be too many levels of TARGS. Remove some of them
3166 here. */
3168 tree new_targs;
3175 }
3178 }
3180 /* If we thought that the DECL was a member function, but it
3181 turns out to be specializing a static member function,
3182 make DECL a static member function as well. */
3188 /* If this is a specialization of a member template of a
3189 template class, we want to return the TEMPLATE_DECL, not
3190 the specialization of it. */
3192 {
3197 {
3198 tree parm;
3202 /* We want to use the argument list specified in the
3203 definition, not in the original declaration. */
3208 }
3213 }
3215 /* Set up the DECL_TEMPLATE_INFO for DECL. */
3221 /* Inherit default function arguments from the template
3222 DECL is specializing. */
3226 /* This specialization has the same protection as the
3227 template it specializes. */
3231 /* 7.1.1-1 [dcl.stc]
3233 A storage-class-specifier shall not be specified in an
3234 explicit specialization...
3236 The parser rejects these, so unless action is taken here,
3237 explicit function specializations will always appear with
3238 global linkage.
3240 The action recommended by the C++ CWG in response to C++
3241 defect report 605 is to make the storage class and linkage
3242 of the explicit specialization match the templated function:
3244 http://www.open-std.org/jtc1/sc22/wg21/docs/cwg_active.html#605
3245 */
3247 {
3251 /* This specialization has the same linkage and visibility as
3252 the function template it specializes. */
3255 {
3258 }
3261 {
3264 }
3265 }
3267 /* If DECL is a friend declaration, declared using an
3268 unqualified name, the namespace associated with DECL may
3269 have been set incorrectly. For example, in:
3271 template <typename T> void f(T);
3272 namespace N {
3273 struct S { friend void f<int>(int); }
3274 }
3276 we will have set the DECL_CONTEXT for the friend
3277 declaration to N, rather than to the global namespace. */
3282 /* This is not really a declaration of a specialization.
3283 It's just the name of an instantiation. But, it's not
3284 a request for an instantiation, either. */
3287 /* A specialization is not necessarily COMDAT. */
3293 /* If this is a full specialization, register it so that we can find
3294 it again. Partial specializations will be registered in
3295 process_partial_specialization. */
3297 {
3302 }
3304 /* If this is a specialization, splice any contracts that may have
3305 been inherited from the template, removing them. */
3309 /* A 'structor should already have clones. */
3315 }
3316 }
3319 }
3321 /* Returns 1 iff PARMS1 and PARMS2 are identical sets of template
3322 parameters. These are represented in the same format used for
3323 DECL_TEMPLATE_PARMS. */
3325 int
3327 {
3342 {
3346 /* If either of the template parameters are invalid, assume
3347 they match for the sake of error recovery. */
3360 }
3363 }
3365 /* Returns true if two template parameters are declared with
3366 equivalent constraints. */
3368 static bool
3370 {
3378 }
3380 /* Returns true when two template parameters are equivalent. */
3382 static bool
3384 {
3388 /* If either of the template parameters are invalid, assume
3389 they match for the sake of error recovery. */
3393 /* ... they declare parameters of the same kind. */
3397 /* ... one parameter was introduced by a parameter declaration, then
3398 both are. This case arises as a result of eagerly rewriting declarations
3399 during parsing. */
3404 /* ... if either declares a pack, they both do. */
3409 {
3410 /* ... if they declare non-type parameters, the types are equivalent. */
3413 }
3415 {
3416 /* ... if they declare template template parameters, their template
3417 parameter lists are equivalent. */
3420 }
3422 /* ... if they are declared with a qualified-concept name, they both
3423 are, and those names are equivalent. */
3425 }
3427 /* Returns true if two template parameters lists are equivalent.
3428 Two template parameter lists are equivalent if they have the
3429 same length and their corresponding parameters are equivalent.
3431 PARMS1 and PARMS2 are TREE_LISTs containing TREE_VECs: the
3432 data structure returned by DECL_TEMPLATE_PARMS.
3434 This is generally the same implementation as comp_template_parms
3435 except that it also the concept names and arguments used to
3436 introduce parameters. */
3438 static bool
3440 {
3451 {
3456 }
3459 }
3461 /* Return true if the requires-clause of the template parameter lists are
3462 equivalent and false otherwise. */
3463 static bool
3465 {
3473 }
3475 /* Returns true if two template heads are equivalent. 17.6.6.1p6:
3476 Two template heads are equivalent if their template parameter
3477 lists are equivalent and their requires clauses are equivalent.
3479 In pre-C++20, this is equivalent to calling comp_template_parms
3480 for the template parameters of TMPL1 and TMPL2. */
3482 bool
3484 {
3488 /* ... have the same number of template parameters, and their
3489 corresponding parameters are equivalent. */
3493 /* ... if either has a requires-clause, they both do and their
3494 corresponding constraint-expressions are equivalent. */
3496 }
3498 /* Determine whether PARM is a parameter pack. */
3500 bool
3502 {
3503 /* Determine if we have a non-type template parameter pack. */
3510 /* If this is a list of template parameters, we could get a
3511 TYPE_DECL or a TEMPLATE_DECL. */
3515 /* Otherwise it must be a type template parameter. */
3519 }
3521 /* Determine if T is a function parameter pack. */
3523 bool
3525 {
3529 }
3531 /* Return the function template declaration of PRIMARY_FUNC_TMPL_INST.
3532 PRIMARY_FUNC_TMPL_INST is a primary function template instantiation. */
3534 tree
3536 {
3543 }
3545 /* Return true iff the function parameter PARAM_DECL was expanded
3546 from the function parameter pack PACK. */
3548 bool
3550 {
3555 /* The parameter pack and its pack arguments have the same
3556 DECL_PARM_INDEX. */
3558 }
3560 /* Determine whether ARGS describes a variadic template args list,
3561 i.e., one that is terminated by a template argument pack. */
3563 static bool
3565 {
3567 tree last_parm;
3581 }
3583 /* Generate a new name for the parameter pack name NAME (an
3584 IDENTIFIER_NODE) that incorporates its */
3586 static tree
3588 {
3589 /* Munge the name to include the parameter index. */
3590 #define NUMBUF_LEN 128
3604 }
3606 /* Return true if T is a primary function, class or alias template
3607 specialization, not including the template pattern. */
3609 bool
3611 {
3627 }
3629 /* Return true if PARM is a template template parameter. */
3631 bool
3633 {
3635 }
3637 /* Return true iff PARM is a DECL representing a type template
3638 parameter. */
3640 bool
3642 {
3647 }
3649 /* Return the template parameters of T if T is a
3650 primary template instantiation, NULL otherwise. */
3652 tree
3654 {
3659 parms = INNERMOST_TEMPLATE_PARMS
3663 }
3665 /* Returns the template arguments of T if T is a template instantiation,
3666 NULL otherwise. */
3668 tree
3670 {
3678 }
3680 /* Return the argument pack elements of T if T is a template argument pack,
3681 NULL otherwise. */
3683 tree
3685 {
3691 }
3693 /* In an ARGUMENT_PACK_SELECT, the actual underlying argument that the
3694 ARGUMENT_PACK_SELECT represents. */
3696 static tree
3698 {
3702 /* If the selected argument is an expansion E, that most likely means we were
3703 called from gen_elem_of_pack_expansion_instantiation during the
3704 substituting of an argument pack (of which the Ith element is a pack
3705 expansion, where I is ARGUMENT_PACK_SELECT_INDEX) into a pack expansion.
3706 In this case, the Ith element resulting from this substituting is going to
3707 be a pack expansion, which pattern is the pattern of E. Let's return the
3708 pattern of E, and gen_elem_of_pack_expansion_instantiation will build the
3709 resulting pack expansion from it. */
3711 {
3712 /* Make sure we aren't throwing away arg info. */
3715 }
3718 }
3720 /* Return a modification of ARGS that's suitable for preserving inside a hash
3721 table. In particular, this replaces each ARGUMENT_PACK_SELECT with its
3722 underlying argument. ARGS is copied (upon modification) iff COW_P. */
3724 static tree
3726 {
3731 {
3733 tree r;
3740 else
3743 {
3745 {
3748 }
3750 }
3751 }
3754 }
3756 /* True iff FN is a function representing a built-in variadic parameter
3757 pack. */
3759 bool
3761 {
3771 }
3773 /* True iff CALL is a call to a function representing a built-in variadic
3774 parameter pack. */
3776 static bool
3778 {
3782 }
3784 /* Return a TREE_VEC for the expansion of __integer_pack(HI). */
3786 static tree
3788 tree in_decl)
3789 {
3794 {
3796 {
3799 }
3804 }
3805 else
3806 {
3811 /* Calculate the largest value of len that won't make the size of the vec
3812 overflow an int. The compiler will exceed resource limits long before
3813 this, but it seems a decent place to diagnose. */
3817 {
3821 max);
3823 }
3831 }
3832 }
3834 /* Return a TREE_VEC for the expansion of built-in template parameter pack
3835 CALL. */
3837 static tree
3839 tree in_decl)
3840 {
3850 }
3852 /* Return true if the tree T has the extra args mechanism for
3853 avoiding partial instantiation. */
3855 static bool
3857 {
3863 }
3865 /* Return *_EXTRA_ARGS of the given supported tree T. */
3869 {
3883 }
3885 /* Structure used to track the progress of find_parameter_packs_r. */
3886 struct find_parameter_pack_data
3887 {
3888 /* TREE_LIST that will contain all of the parameter packs found by
3889 the traversal. */
3892 /* Set of AST nodes that have been visited by the traversal. */
3895 /* True iff we found a subtree that has the extra args mechanism. */
3897 };
3899 /* Identifies all of the argument packs that occur in a template
3900 argument and appends them to the TREE_LIST inside DATA, which is a
3901 find_parameter_pack_data structure. This is a subroutine of
3902 make_pack_expansion and uses_parameter_packs. */
3903 static tree
3905 {
3911 #define WALK_SUBTREE(NODE) \
3912 cp_walk_tree (&(NODE), &find_parameter_packs_r, \
3913 ppd, ppd->visited) \
3915 /* Don't look through typedefs; we are interested in whether a
3916 parameter pack is actually written in the expression/type we're
3917 looking at, not the target type. */
3919 {
3920 /* But do look at arguments for an alias template. */
3927 }
3929 /* Identify whether this is a parameter pack or not. */
3931 {
3939 /* FALLTHRU */
3948 {
3949 /* We don't want to walk into the type of a PARM_DECL,
3950 because we don't want to see the type parameter pack. */
3953 }
3958 {
3959 /* We don't want to walk into the type of a variadic capture proxy,
3960 because we don't want to see the type parameter pack. */
3963 }
3965 {
3967 find_parameter_packs_r,
3970 }
3982 /* Not a parameter pack. */
3984 }
3987 {
3988 /* Add this parameter pack to the list. */
3990 }
3999 /* This switch statement will return immediately if we don't find a
4000 parameter pack. ??? Should some of these be in cp_walk_subtrees? */
4002 {
4004 /* Check the template itself. */
4010 {
4012 /* Ignore the declaration of a capture proxy for a parameter pack. */
4016 /* Since we stop at typedefs above, we need to look through them at
4017 the point of the DECL_EXPR. */
4021 }
4048 {
4049 /* Since we defer implicit capture, look in the parms and body. */
4056 }
4071 /* Don't walk into IF_STMT_EXTRA_ARGS. */
4078 {
4079 /* Local class, need to look through the whole definition.
4080 TYPE_BINFO might be unset for a partial instantiation. */
4085 }
4086 else
4087 /* Enum, look at the values. */
4101 }
4103 #undef WALK_SUBTREE
4106 }
4108 /* Determines if the expression or type T uses any parameter packs. */
4109 tree
4111 {
4119 }
4121 /* Turn ARG, which may be an expression, type, or a TREE_LIST
4122 representation a base-class initializer into a parameter pack
4123 expansion. If all goes well, the resulting node will be an
4124 EXPR_PACK_EXPANSION, TYPE_PACK_EXPANSION, or TREE_LIST,
4125 respectively. */
4126 tree
4128 {
4129 tree result;
4138 {
4139 /* A TREE_LIST with a non-null TREE_PURPOSE is for a base
4140 class initializer. In this case, the TREE_PURPOSE will be a
4141 _TYPE node (representing the base class expansion we're
4142 initializing) and the TREE_VALUE will be a TREE_LIST
4143 containing the initialization arguments.
4145 The resulting expansion looks somewhat different from most
4146 expansions. Rather than returning just one _EXPANSION, we
4147 return a TREE_LIST whose TREE_PURPOSE is a
4148 TYPE_PACK_EXPANSION containing the bases that will be
4149 initialized. The TREE_VALUE will be identical to the
4150 original TREE_VALUE, which is a list of arguments that will
4151 be passed to each base. We do not introduce any new pack
4152 expansion nodes into the TREE_VALUE (although it is possible
4153 that some already exist), because the TREE_PURPOSE and
4154 TREE_VALUE all need to be expanded together with the same
4155 _EXPANSION node. Note that the TYPE_PACK_EXPANSION in the
4156 resulting TREE_PURPOSE will mention the parameter packs in
4157 both the bases and the arguments to the bases. */
4158 tree purpose;
4159 tree value;
4162 /* Determine which parameter packs will be used by the base
4163 class expansion. */
4171 {
4174 arg);
4177 }
4180 {
4181 /* Collect the sets of parameter packs used in each of the
4182 initialization arguments. */
4184 {
4185 /* Determine which parameter packs will be expanded in this
4186 argument. */
4189 }
4190 }
4194 /* Create the pack expansion type for the base type. */
4200 /* Just use structural equality for these TYPE_PACK_EXPANSIONS;
4201 they will rarely be compared to anything. */
4205 }
4210 /* Build the PACK_EXPANSION_* node. */
4211 result = for_types
4216 {
4217 /* Propagate type and const-expression information. */
4220 /* Mark this read now, since the expansion might be length 0. */
4222 }
4223 else
4224 /* Just use structural equality for these TYPE_PACK_EXPANSIONS;
4225 they will rarely be compared to anything. */
4228 /* Determine which parameter packs will be expanded. */
4234 /* Make sure we found some parameter packs. */
4236 {
4238 {
4241 else
4243 }
4245 }
4250 /* If the pattern of this pack expansion contains a subtree that has
4251 the extra args mechanism for avoiding partial instantiation, then
4252 force this pack expansion to also use extra args. Otherwise
4253 partial instantiation of this pack expansion may not lower the
4254 level of some parameter packs within the pattern, which would
4255 confuse tsubst_pack_expansion later (PR101764). */
4259 }
4261 /* Checks T for any "bare" parameter packs, which have not yet been
4262 expanded, and issues an error if any are found. This operation can
4263 only be done on full expressions or types (e.g., an expression
4264 statement, "if" condition, etc.), because we could have expressions like:
4266 foo(f(g(h(args)))...)
4268 where "args" is a parameter pack. check_for_bare_parameter_packs
4269 should not be called for the subexpressions args, h(args),
4270 g(h(args)), or f(g(h(args))), because we would produce erroneous
4271 error messages.
4273 Returns TRUE and emits an error if there were bare parameter packs,
4274 returns FALSE otherwise. */
4275 bool
4277 {
4298 /* It's OK for a lambda to have an unexpanded parameter pack from the
4299 containing context, but do complain about unexpanded capture packs. */
4305 {
4306 /* We're in a lambda, but it isn't the innermost class.
4307 This should work, but currently doesn't. */
4310 }
4315 {
4321 }
4324 {
4325 auto_diagnostic_group d;
4328 {
4339 else
4344 else
4348 }
4351 }
4354 }
4356 /* Expand any parameter packs that occur in the template arguments in
4357 ARGS. */
4358 tree
4360 {
4369 /* First, determine if we need to expand anything, and the number of
4370 slots we'll need. */
4372 {
4377 {
4381 else
4383 }
4384 else
4385 {
4387 num_result_args++;
4388 }
4389 }
4391 /* If no expansion is necessary, we're done. */
4395 /* Expand arguments. */
4398 non_default_args_count =
4401 {
4404 {
4411 }
4412 else
4413 {
4416 }
4417 }
4421 }
4423 /* Checks if DECL shadows a template parameter.
4425 [temp.local]: A template-parameter shall not be redeclared within its
4426 scope (including nested scopes).
4428 Emits an error and returns TRUE if the DECL shadows a parameter,
4429 returns FALSE otherwise. */
4431 bool
4433 {
4434 tree olddecl;
4436 /* If we're not in a template, we can't possibly shadow a template
4437 parameter. */
4441 /* Figure out what we're shadowing. */
4445 /* If there's no previous binding for this name, we're not shadowing
4446 anything, let alone a template parameter. */
4450 /* If we're not shadowing a template parameter, we're done. Note
4451 that OLDDECL might be an OVERLOAD (or perhaps even an
4452 ERROR_MARK), so we can't just blithely assume it to be a _DECL
4453 node. */
4457 /* We check for decl != olddecl to avoid bogus errors for using a
4458 name inside a class. We check TPFI to avoid duplicate errors for
4459 inline member templates. */
4465 /* Don't complain about the injected class name, as we've already
4466 complained about the class itself. */
4470 auto_diagnostic_group d;
4474 else
4479 }
4481 /* Return a new TEMPLATE_PARM_INDEX with the indicated INDEX, LEVEL,
4482 ORIG_LEVEL, DECL, and TYPE. */
4484 static tree
4488 tree decl,
4489 tree type)
4490 {
4501 }
4504 {
4506 {
4513 {
4514 val
4518 }
4523 }
4526 {
4531 }
4532 };
4536 /* Find the canonical type parameter for the given template type
4537 parameter. Returns the canonical type parameter, which may be TYPE
4538 if no such parameter existed. */
4540 tree
4542 {
4550 }
4552 /* Return a TEMPLATE_PARM_INDEX, similar to INDEX, but whose
4553 TEMPLATE_PARM_LEVEL has been decreased by LEVELS. If such a
4554 TEMPLATE_PARM_INDEX already exists, it is returned; otherwise, a
4555 new one is created. */
4557 static tree
4559 tsubst_flags_t complain)
4560 {
4565 {
4570 type);
4585 /* Template template parameters need this. */
4588 {
4600 }
4602 /* Attach the TPI to the decl. */
4605 else
4607 }
4610 }
4612 /* Process information from new template parameter PARM and append it
4613 to the LIST being built. This new parameter is a non-type
4614 parameter iff IS_NON_TYPE is true. This new parameter is a
4615 parameter pack iff IS_PARAMETER_PACK is true. The location of PARM
4616 is in PARM_LOC. */
4618 tree
4621 {
4627 {
4637 }
4644 {
4650 {
4651 /* [temp.param]
4653 The top-level cv-qualifiers on the template-parameter are
4654 ignored when determining its type. */
4659 && !is_parameter_pack
4660 /* If we're in a nested template parameter list, the template
4661 template parameter could be a parameter pack. */
4663 {
4664 /* This template parameter is not a parameter pack, but it
4665 should be. Complain about "bare" parameter packs. */
4668 /* Recover by calling this a parameter pack. */
4670 }
4671 }
4673 /* A template parameter is not modifiable. */
4682 current_template_depth,
4687 }
4688 else
4689 {
4690 tree t;
4694 {
4696 /* This is for distinguishing between real templates and template
4697 template parameters */
4700 /* any_template_parm_r expects to be able to get the targs of a
4701 DECL_TEMPLATE_RESULT. */
4710 }
4711 else
4712 {
4714 /* parm is either IDENTIFIER_NODE or NULL_TREE. */
4717 }
4724 current_template_depth,
4728 }
4736 /* Build requirements for the type/template parameter.
4737 This must be done after SET_DECL_TEMPLATE_PARM_P or
4738 process_template_parm could fail. */
4745 /* Build the parameter node linking the parameter declaration,
4746 its default argument (if any), and its constraints (if any). */
4752 else
4756 }
4758 /* The end of a template parameter list has been reached. Process the
4759 tree list into a parameter vector, converting each parameter into a more
4760 useful form. Type parameters are saved as IDENTIFIER_NODEs, and others
4761 as PARM_DECLs. */
4763 tree
4765 {
4768 /* Pop the dummy parameter level and add the real one. We do not
4769 morph the dummy parameter in place, as it might have been
4770 captured by a (nested) template-template-parm. */
4773 current_template_parms
4778 {
4784 }
4789 }
4791 // Explicitly indicate the end of the template parameter list. We assume
4792 // that the current template parameters have been constructed and/or
4793 // managed explicitly, as when creating new template template parameters
4794 // from a shorthand constraint.
4795 void
4797 {
4799 }
4801 /* end_template_decl is called after a template declaration is seen. */
4803 void
4805 {
4811 /* This matches the pushlevel in begin_template_parm_list. */
4816 }
4818 /* Takes a TEMPLATE_PARM_P or DECL_TEMPLATE_PARM_P node or a TREE_LIST
4819 thereof, and converts it into an argument suitable to be passed to
4820 the type substitution functions. Note that if the TREE_LIST contains
4821 an error_mark node, the returned argument is error_mark_node. */
4823 tree
4825 {
4836 {
4840 else
4842 }
4848 {
4850 {
4851 /* Turn this argument into a TYPE_ARGUMENT_PACK
4852 with a single element, which expands T. */
4861 }
4862 }
4863 else
4864 {
4866 {
4867 /* Turn this argument into a NONTYPE_ARGUMENT_PACK
4868 with a single element, which expands T. */
4878 }
4879 else
4881 }
4883 }
4885 /* If T looks like a generic template argument produced by template_parm_to_arg,
4886 return the corresponding template parameter, otherwise return NULL_TREE. */
4888 static tree
4890 {
4895 {
4900 }
4907 else
4909 }
4911 /* Given a single level of template parameters (a TREE_VEC), return it
4912 as a set of template arguments. */
4914 tree
4916 {
4926 }
4928 /* Given a set of template parameters, return them as a set of template
4929 arguments. The template parameters are represented as a TREE_VEC, in
4930 the form documented in cp-tree.h for template arguments. */
4932 tree
4934 {
4935 tree header;
4940 /* If there is only one level of template parameters, we do not
4941 create a TREE_VEC of TREE_VECs. Instead, we return a single
4942 TREE_VEC containing the arguments. */
4947 {
4952 else
4954 }
4957 }
4959 /* Within the declaration of a template, return the currently active
4960 template parameters as an argument TREE_VEC. */
4962 static tree
4964 {
4966 }
4968 /* Return the fully generic arguments for of TMPL, i.e. what
4969 current_template_args would be while parsing it. */
4971 tree
4973 {
4978 /* DECL_TEMPLATE_RESULT doesn't have the arguments we want. For a template
4979 template parameter, it has no TEMPLATE_INFO; for a partial
4980 specialization, it has the arguments for the primary template, and we
4986 }
4988 /* Return the template arguments corresponding to the template parameters of
4989 DECL's enclosing scope. When DECL is a member of a partial specialization,
4990 this returns the arguments for the partial specialization as opposed to those
4991 for the primary template, which is the main difference between this function
4992 and simply using e.g. the TYPE_TI_ARGS of DECL's DECL_CONTEXT. */
4994 tree
4996 {
5008 }
5010 /* Update the declared TYPE by doing any lookups which were thought to be
5011 dependent, but are not now that we know the SCOPE of the declarator. */
5013 tree
5015 {
5026 /* Don't bother building up the args in this case. */
5028 {
5029 /* tsubst in the args corresponding to the template parameters,
5030 including auto if present. Most things will be unchanged, but
5031 make_typename_type and tsubst_qualified_id will resolve
5032 TYPENAME_TYPEs and SCOPE_REFs that were previously dependent. */
5035 tree pushed;
5037 {
5041 }
5046 }
5052 {
5055 else
5057 }
5059 }
5061 /* Return a TEMPLATE_DECL corresponding to DECL, using the indicated
5062 template PARMS and constraints, CONSTR. If MEMBER_TEMPLATE_P is true,
5063 the new template is a member template. */
5065 static tree
5067 {
5079 /* Propagate module information from the decl. */
5083 }
5085 struct template_parm_data
5086 {
5087 /* The level of the template parameters we are currently
5088 processing. */
5091 /* The index of the specialization argument we are currently
5092 processing. */
5095 /* An array whose size is the number of template parameters. The
5096 elements are nonzero if the parameter has been used in any one
5097 of the arguments processed so far. */
5100 /* An array whose size is the number of template arguments. The
5101 elements are nonzero if the argument makes use of template
5102 parameters of this level. */
5104 };
5106 /* Subroutine of push_template_decl used to see if each template
5107 parameter in a partial specialization is used in the explicit
5108 argument list. If T is of the LEVEL given in DATA (which is
5109 treated as a template_parm_data*), then DATA->PARMS is marked
5110 appropriately. */
5112 static int
5114 {
5122 {
5125 }
5127 /* In C++17 the type of a non-type argument is a deduced context. */
5132 data,
5133 NULL,
5136 /* Return zero so that for_each_template_parm will continue the
5137 traversal of the tree; we want to mark *every* template parm. */
5139 }
5141 /* Process the partial specialization DECL. */
5143 static tree
5145 {
5152 tree inner_parms;
5153 tree inst;
5165 /* We check that each of the template parameters given in the
5166 partial specialization is used in the argument list to the
5167 specialization. For example:
5169 template <class T> struct S;
5170 template <class T> struct S<T*>;
5172 The second declaration is OK because `T*' uses the template
5173 parameter T, whereas
5175 template <class T> struct S<int>;
5177 is no good. Even trickier is:
5179 template <class T>
5180 struct S1
5181 {
5182 template <class U>
5183 struct S2;
5184 template <class U>
5185 struct S2<T>;
5186 };
5188 The S2<T> declaration is actually invalid; it is a
5189 full-specialization. Of course,
5191 template <class U>
5192 struct S2<T (*)(U)>;
5194 or some such would have been OK. */
5202 {
5207 NULL,
5209 }
5211 {
5212 auto_diagnostic_group d;
5216 {
5217 /* One of the template parms was not used in a deduced context in the
5218 specialization. */
5220 {
5224 }
5228 }
5232 }
5234 /* [temp.class.spec]
5236 The argument list of the specialization shall not be identical to
5237 the implicit argument list of the primary template. */
5238 tree main_args
5241 && (!flag_concepts
5243 {
5244 auto_diagnostic_group d;
5247 "any template arguments; to define the primary template, "
5249 else
5251 "template arguments and is not more constrained than "
5252 "the primary template; to define the primary template, "
5255 }
5257 /* A partial specialization that replaces multiple parameters of the
5258 primary template with a pack expansion is less specialized for those
5259 parameters. */
5261 {
5262 auto_diagnostic_group d;
5264 "primary template because it replaces multiple parameters "
5267 /* Avoid crash in process_partial_specialization. */
5269 }
5272 {
5273 auto_diagnostic_group d;
5276 /* Avoid crash below. */
5278 }
5280 /* If we aren't in a dependent class, we can actually try deduction. */
5282 /* FIXME we should be able to handle a partial specialization of a
5283 partial instantiation, but currently we can't (c++/41727). */
5286 {
5287 auto_diagnostic_group d;
5290 decl))
5292 maintmpl);
5293 }
5295 /* [temp.spec.partial]
5297 The type of a template parameter corresponding to a specialized
5298 non-type argument shall not be dependent on a parameter of the
5299 specialization.
5301 Also, we verify that pack expansions only occur at the
5302 end of the argument list. */
5305 {
5312 {
5313 /* Extract the arguments from the argument pack. We'll be
5314 iterating over these in the following loop. */
5317 }
5320 {
5322 /* Get the Jth argument in the parameter pack. */
5326 {
5327 /* Pack expansions must come at the end of the
5328 argument list. */
5331 {
5335 else
5338 }
5339 }
5342 /* We only care about the pattern. */
5348 /* This next two lines are the `argument expression is not just a
5349 simple identifier' condition and also the `specialized
5350 non-type argument' bit. */
5355 {
5356 /* Look at the corresponding template parameter,
5357 marking which template parameters its type depends
5358 upon. */
5362 {
5363 /* We haven't yet initialized TPD2. Do so now. */
5365 /* The number of parameters here is the number in the
5366 main template, which, as checked in the assertion
5367 above, is NARGS. */
5371 }
5373 /* Mark the template parameters. But this time, we're
5374 looking for the template parameters of the main
5375 template, not in the specialization. */
5382 NULL,
5386 {
5387 /* The type depended on some template parameters.
5388 If they are fully specialized in the
5389 specialization, that's OK. */
5398 "type %qT of template argument %qE depends "
5400 "type %qT of template argument %qE depends "
5402 type,
5403 arg);
5404 }
5405 }
5406 }
5407 }
5409 /* We should only get here once. */
5413 // Build the template decl.
5420 /* Give template template parms a DECL_CONTEXT of the template
5421 for which they are a parameter. */
5423 {
5427 }
5430 {
5431 /* We didn't register this in check_explicit_specialization so we could
5432 wait until the constraints were set. */
5435 /* Redeclaration. */
5437 }
5438 else
5445 /* Link the DECL_TEMPLATE_RESULT back to the partial TEMPLATE_DECL. */
5453 {
5459 {
5468 "declaration of %qD ambiguates earlier template "
5472 "partial specialization of %qD after instantiation "
5474 }
5475 }
5478 }
5480 /* PARM is a template parameter of some form; return the corresponding
5481 TEMPLATE_PARM_INDEX. */
5483 static tree
5485 {
5498 }
5500 /* Subroutine of fixed_parameter_pack_p below. Look for any template
5501 parameter packs used by the template parameter PARM. */
5503 static void
5505 {
5506 /* A type parm can't refer to another parm. */
5510 {
5514 }
5520 {
5524 else
5526 }
5527 }
5529 /* PARM is a template parameter pack. Return any parameter packs used in
5530 its type or the type of any of its template parameters. If there are
5531 any such packs, it will be instantiated into a fixed template parameter
5532 list by partial instantiation rather than be fully deduced. */
5534 tree
5536 {
5537 /* This can only be true in a member template. */
5540 /* This can only be true for a parameter pack. */
5543 /* A type parm can't refer to another parm. */
5556 }
5558 /* Check that a template declaration's use of default arguments and
5559 parameter packs is not invalid. Here, PARMS are the template
5560 parameters. IS_PRIMARY is true if DECL is the thing declared by
5561 a primary template. IS_PARTIAL is true if DECL is a partial
5562 specialization.
5564 IS_FRIEND_DECL is nonzero if DECL is either a non-defining friend
5565 function template declaration or a friend class template
5566 declaration. In the function case, 1 indicates a declaration, 2
5567 indicates a redeclaration. When IS_FRIEND_DECL=2, no errors are
5568 emitted for extraneous default arguments.
5570 Returns TRUE if there were no errors found, FALSE otherwise. */
5572 bool
5575 {
5578 tree parm_level;
5581 /* [temp.param]
5583 A default template-argument shall not be specified in a
5584 function template declaration or a function template definition, nor
5585 in the template-parameter-list of the definition of a member of a
5586 class template. */
5590 /* You can't have a function template declaration in a local
5591 scope, nor you can you define a member of a class template in a
5592 local scope. */
5600 /* A lambda doesn't have an explicit declaration; don't complain
5601 about the parms of the enclosing class. */
5608 /* If this is either a friend defined in the scope of the class
5609 or a member function. */
5615 /* And, if it was a member function, it really was defined in
5616 the scope of the class. */
5619 /* We already checked these parameters when the template was
5620 declared, so there's no need to do it again now. This function
5621 was defined in class scope, but we're processing its body now
5622 that the class is complete. */
5625 /* Core issue 226 (C++0x only): the following only applies to class
5626 templates. */
5629 {
5630 /* [temp.param]
5632 If a template-parameter has a default template-argument, all
5633 subsequent template-parameters shall have a default
5634 template-argument supplied. */
5636 {
5643 {
5653 {
5655 /* For better subsequent error-recovery, we indicate that
5656 there should have been a default argument. */
5659 }
5661 && !is_friend_decl
5662 /* Don't complain about an enclosing partial
5663 specialization. */
5668 /* A fixed parameter pack will be partially
5669 instantiated into a fixed length list. */
5671 {
5672 /* A primary class template, primary variable template
5673 (DR 2032), or alias template can only have one
5674 parameter pack, at the end of the template
5675 parameter list. */
5683 }
5684 }
5685 }
5686 }
5689 || is_partial
5690 || !is_primary
5692 /* For an ordinary class template, default template arguments are
5693 allowed at the innermost level, e.g.:
5694 template <class T = int>
5695 struct S {};
5696 but, in a partial specialization, they're not allowed even
5697 there, as we have in [temp.class.spec]:
5699 The template parameter list of a specialization shall not
5700 contain default template argument values.
5702 So, for a partial specialization, or for a function template
5703 (in C++98/C++03), we look at all of them. */
5704 ;
5705 else
5706 /* But, for a primary class template that is not a partial
5707 specialization we look at all template parameters except the
5708 innermost ones. */
5711 /* Figure out what error message to issue. */
5726 else
5727 /* Per [temp.param]/9, "A default template-argument shall not be
5728 specified in the template-parameter-lists of the definition of
5729 a member of a class template that appears outside of the member's
5730 class.", thus if we aren't handling a member of a class template
5731 there is no need to examine the parameters. */
5735 /* If we're inside a class definition, there's no need to
5736 examine the parameters to the class itself. On the one
5737 hand, they will be checked when the class is defined, and,
5738 on the other, default arguments are valid in things like:
5739 template <class T = double>
5740 struct S { template <class U> void f(U); };
5741 Here the default argument for `S' has no bearing on the
5742 declaration of `f'. */
5744 else
5745 /* Check everything. */
5751 {
5758 {
5763 {
5765 {
5772 }
5774 /* Clear out the default argument so that we are not
5775 confused later. */
5777 }
5778 }
5780 /* At this point, if we're still interested in issuing messages,
5781 they must apply to classes surrounding the object declared. */
5785 }
5788 }
5790 /* Worker for push_template_decl_real, called via
5791 for_each_template_parm. DATA is really an int, indicating the
5792 level of the parameters we are interested in. If T is a template
5793 parameter of that level, return nonzero. */
5795 static int
5797 {
5803 else
5806 }
5808 /* Worker for uses_outer_template_parms, called via for_each_template_parm.
5809 DATA is really an int, indicating the innermost outer level of parameters.
5810 If T is a template parameter of that level or further out, return
5811 nonzero. */
5813 static int
5815 {
5821 else
5824 }
5826 /* Creates a TEMPLATE_DECL for the indicated DECL using the template
5827 parameters given by current_template_args, or reuses a
5828 previously existing one, if appropriate. Returns the DECL, or an
5829 equivalent one, if it is replaced via a call to duplicate_decls.
5831 If IS_FRIEND is true, DECL is a friend declaration. */
5833 tree
5835 {
5839 /* See if this is a partial specialization. */
5848 /* No surprising friend functions. */
5853 tree ctx;
5855 /* For a friend, we want the context of the friend, not
5856 the type of which it is a friend. */
5860 /* In the case of a virtual function, we want the class in which
5861 it is defined. */
5863 else
5864 /* Otherwise, if we're currently defining some class, the DECL
5865 is assumed to be a member of the class. */
5874 /* See if this is a primary template. */
5878 /* A friend template that specifies a class context, i.e.
5879 template <typename T> friend void A<T>::f();
5880 is not primary. */
5881 ;
5883 /* Lambdas are not primary. */
5884 ;
5885 else
5888 /* True if the template is a member template, in the sense of
5889 [temp.mem]. */
5893 {
5901 {
5904 }
5906 {
5908 {
5911 }
5913 {
5914 /* [temp.mem]
5916 A destructor shall not be a member template. */
5920 }
5927 {
5928 /* [basic.stc.dynamic.allocation]
5930 An allocation function can be a function
5931 template. ... Template allocation functions shall
5932 have two or more parameters. */
5935 }
5936 }
5942 /* alias-declaration */
5948 else
5949 {
5952 }
5953 }
5960 /* Check to see that the rules regarding the use of default
5961 arguments are not being violated. We check args for a friend
5962 functions when we know whether it's a definition, introducing
5963 declaration or re-declaration. */
5968 /* Ensure that there are no parameter packs in the type of this
5969 declaration that have not been expanded. */
5971 {
5972 /* Check each of the arguments individually to see if there are
5973 any bare parameter packs. */
5979 {
5982 {
5983 /* This is a PARM_DECL that contains unexpanded parameter
5984 packs. We have already complained about this in the
5985 check_for_bare_parameter_packs call, so just replace
5986 these types with ERROR_MARK_NODE. */
5989 }
5993 }
5995 /* Check for bare parameter packs in the return type and the
5996 exception specifiers. */
5998 /* Errors were already issued, set return type to int
5999 as the frontend doesn't expect error_mark_node as
6000 the return type. */
6004 }
6005 else
6006 {
6010 {
6013 }
6018 }
6027 {
6028 /* Does not get a template head. */
6031 }
6038 {
6043 /* If DECL is a TYPE_DECL for a class-template, then there won't
6044 be DECL_LANG_SPECIFIC. The information equivalent to
6045 DECL_TEMPLATE_INFO is found in TYPE_TEMPLATE_INFO instead. */
6049 {
6050 /* Since a template declaration already existed for this
6051 class-type, we must be redeclaring it here. Make sure
6052 that the redeclaration is valid. */
6054 current_template_parms,
6056 /* We don't need to create a new TEMPLATE_DECL; just use the
6057 one we already had. */
6059 }
6060 else
6061 {
6063 member_template_p);
6068 {
6069 /* A specialization of a member template of a template
6070 class. */
6074 }
6075 }
6076 }
6077 else
6078 {
6084 {
6087 }
6095 {
6096 /* The declaration is a specialization of a member
6097 template, declared outside the class. Therefore, the
6098 innermost template arguments will be NULL, so we
6099 replace them with the arguments determined by the
6100 earlier call to check_explicit_specialization. */
6103 tree new_tmpl
6105 member_template_p);
6113 args,
6116 }
6118 /* Make sure the template headers we got make sense. */
6123 {
6128 }
6129 else
6131 {
6136 {
6140 else
6144 /* Avoid crash in import_export_decl. */
6147 }
6152 /* Can happen in erroneous input. */
6154 else
6156 }
6158 /* Check that the parms are used in the appropriate qualifying scopes
6159 in the declarator. */
6163 {
6164 auto_diagnostic_group d;
6170 /* Avoid crash in import_export_decl. */
6173 }
6175 /* Check that the constraints for each enclosing template scope are
6176 consistent with the original declarations. */
6178 {
6182 {
6185 }
6187 {
6189 {
6193 }
6196 }
6197 }
6198 }
6203 {
6204 /* Push template declarations for global functions and types.
6205 Note that we do not try to push a global template friend
6206 declared in a template class; such a thing may well depend on
6207 the template parameters of the class and we'll push it when
6208 instantiating the befriending class. */
6211 {
6216 /* pushdecl may have found an existing template. */
6218 {
6221 }
6222 }
6224 {
6225 /* Record this decl as belonging to the current class. It's
6226 not chained onto anything else. */
6230 }
6231 }
6233 /* The type may have been completed, or (erroneously) changed. */
6237 {
6239 {
6244 /* Give template template parms a DECL_CONTEXT of the template
6245 for which they are a parameter. */
6248 {
6252 }
6256 {
6259 {
6260 /* ??? Why don't we do this here for all templates? */
6263 }
6264 }
6265 }
6267 /* The DECL_TI_ARGS of DECL contains full set of arguments
6268 referring wback to its most general template. If TMPL is a
6269 specialization, ARGS may only have the innermost set of
6270 arguments. Add the missing argument levels if necessary. */
6278 else
6279 {
6282 }
6283 }
6288 {
6289 /* Manually mark such aliases as dependent so that dependent_type_p_r
6290 doesn't have to handle them. */
6293 /* The identity of such aliases is hairy; see structural_comptypes. */
6295 }
6298 && !is_friend
6301 /* Set DECL_COMDAT on template instantiations; if we force
6302 them to be emitted by explicit instantiation,
6303 mark_needed will tell cgraph to do the right thing. */
6309 }
6311 /* FN is an inheriting constructor that inherits from the constructor
6312 template INHERITED; turn FN into a constructor template with a matching
6313 template header. */
6315 tree
6317 {
6318 tree inner_parms
6321 tree parms
6330 }
6332 /* Called when a class template TYPE is redeclared with the indicated
6333 template PARMS, e.g.:
6335 template <class T> struct S;
6336 template <class T> struct S {}; */
6338 bool
6340 {
6341 tree tmpl;
6342 tree tmpl_parms;
6346 {
6349 }
6353 /* The type is nested in some template class. Nothing to worry
6354 about here; there are no new template parameters for the nested
6355 type. */
6359 {
6361 tmpl);
6363 }
6369 {
6370 auto_diagnostic_group d;
6380 }
6383 {
6384 tree tmpl_parm;
6385 tree parm;
6397 /* TMPL_PARM and PARM can be either TYPE_DECL, PARM_DECL, or
6398 TEMPLATE_DECL. */
6408 {
6409 auto_diagnostic_group d;
6413 else
6416 }
6418 /* The parameters can be declared to introduce different
6419 constraints. */
6423 {
6424 auto_diagnostic_group d;
6430 }
6432 /* Give each template template parm in this redeclaration a
6433 DECL_CONTEXT of the template for which they are a parameter. */
6435 {
6439 }
6440 }
6449 /* Two classes with different constraints declare different entities. */
6451 {
6452 auto_diagnostic_group d;
6458 }
6461 }
6463 /* The actual substitution part of instantiate_non_dependent_expr,
6464 to be used when the caller has already checked
6465 !instantiation_dependent_uneval_expression_p (expr)
6466 and cleared processing_template_decl. */
6468 tree
6470 {
6472 }
6474 /* Instantiate the non-dependent expression EXPR. */
6476 tree
6479 {
6484 {
6485 /* The caller should have checked this already. */
6487 processing_template_decl_sentinel s;
6489 }
6491 }
6493 /* Like instantiate_non_dependent_expr, but return NULL_TREE if the
6494 expression is dependent or non-constant. */
6496 tree
6498 {
6502 {
6505 else
6506 {
6507 processing_template_decl_sentinel s;
6509 }
6510 }
6512 }
6514 /* True iff T is a specialization of a variable template. */
6516 bool
6518 {
6523 }
6525 /* Return TRUE iff T is a type alias, a TEMPLATE_DECL for an alias
6526 template declaration, or a TYPE_DECL for an alias declaration. */
6528 bool
6530 {
6538 }
6540 /* If T is a specialization of an alias template, return it; otherwise return
6541 NULL_TREE. If TRANSPARENT_TYPEDEFS is true, look through other aliases. */
6543 tree
6546 {
6550 /* It's an alias template specialization if it's an alias and its
6551 TYPE_NAME is a specialization of a primary template. */
6553 {
6560 transparent_typedefs);
6561 }
6564 }
6566 /* A cache of the result of complex_alias_template_p. */
6570 /* Data structure for complex_alias_template_*. */
6572 struct uses_all_template_parms_data
6573 {
6576 };
6578 /* walk_tree callback for complex_alias_template_p. */
6580 static tree
6582 {
6587 {
6592 {
6596 }
6599 }
6604 /* An alias template with a pack expansion that expands a pack from the
6605 enclosing class needs to be considered complex, to avoid confusion with
6606 the same pack being used as an argument to the alias's own template
6607 parameter (91966). */
6610 {
6619 /* Consider the expanded packs to be used outside the expansion... */
6621 }
6623 /* ...but don't walk into the pattern. Consider PR104008:
6625 template <typename T, typename... Ts>
6626 using IsOneOf = disjunction<is_same<T, Ts>...>;
6628 where IsOneOf seemingly uses all of its template parameters in its
6629 expansion (and does not expand a pack from the enclosing class), so the
6630 alias was not marked as complex. However, if it is used like
6631 "IsOneOf<T>", the empty pack for Ts means that T no longer appears in the
6632 expansion. So only Ts is considered used by the pack expansion. */
6636 }
6638 /* An alias template is complex from a SFINAE perspective if a template-id
6639 using that alias can be ill-formed when the expansion is not, as with
6640 the void_t template.
6642 If this predicate returns true in the ordinary case, the out parameter
6643 SEEN_OUT is set to a TREE_VEC containing boolean_true_node at element I if
6644 the I'th template parameter of the alias template is used in the alias. */
6646 static bool
6648 {
6653 /* A renaming alias isn't complex. */
6657 /* Any other constrained alias is complex. */
6661 /* An alias with dependent type attributes is complex. */
6669 {
6679 }
6692 {
6695 }
6699 {
6704 }
6708 }
6710 /* If T is a specialization of a complex alias template with a dependent
6711 argument for an unused template parameter, return it; otherwise return
6712 NULL_TREE. If T is a typedef to such a specialization, return the
6713 specialization. This predicate is usually checked alongside
6714 dependent_opaque_alias_p. Whereas dependent_opaque_alias_p checks
6715 type equivalence of an alias vs its expansion, this predicate more
6716 broadly checks SFINAE equivalence. */
6718 tree
6720 {
6729 {
6732 {
6735 {
6738 }
6739 else
6740 {
6746 }
6749 }
6750 }
6753 {
6756 }
6759 }
6761 /* Return true if substituting into T would yield a different type than
6762 substituting into its expansion. This predicate is usually checked
6763 alongside dependent_alias_template_spec_p. */
6765 bool
6767 {
6772 /* Treat a dependent decltype(lambda) alias as opaque so that we
6773 don't prematurely strip it when used as a template argument.
6774 Otherwise substitution into each occurrence of the (stripped)
6775 alias would incorrectly yield a distinct lambda type. */
6779 }
6781 /* Return the number of innermost template parameters in TMPL. */
6783 static int
6785 {
6788 }
6790 /* Return either TMPL or another template that it is equivalent to under DR
6791 1286: An alias that just changes the name of a template is equivalent to
6792 the other template. */
6794 static tree
6796 {
6799 {
6800 /* Determine if the alias is equivalent to an underlying template. */
6802 /* The underlying type may have been ill-formed. Don't proceed. */
6815 /* Does the alias add cv-quals? */
6823 /* Are any default template arguments equivalent? */
6828 {
6833 }
6835 /* If TMPL adds or changes any constraints, it isn't equivalent. I think
6836 it's appropriate to treat a less-constrained alias as equivalent. */
6840 /* If TMPL adds dependent type attributes, it isn't equivalent. */
6844 /* Alias is equivalent. Strip it and repeat. */
6846 }
6847 top_break:;
6850 }
6852 /* Subroutine of convert_nontype_argument. Converts EXPR to TYPE, which
6853 must be a reference-to-function or a pointer-to-function type, as specified
6854 in [temp.arg.nontype]: disambiguate EXPR if it is an overload set,
6855 and check that the resulting function has external linkage. */
6857 static tree
6859 tsubst_flags_t complain)
6860 {
6863 linkage_kind linkage;
6881 /* [temp.arg.nontype]/1
6883 A template-argument for a non-type, non-template template-parameter
6884 shall be one of:
6885 [...]
6886 -- the address of an object or function with external [C++11: or
6887 internal] linkage. */
6891 {
6893 {
6894 auto_diagnostic_group d;
6901 else
6904 }
6906 }
6911 {
6913 {
6919 else
6923 }
6925 }
6927 accept:
6929 {
6932 else
6934 }
6939 }
6941 /* Subroutine of convert_nontype_argument.
6942 Check if EXPR of type TYPE is a valid pointer-to-member constant.
6943 Emit an error otherwise. */
6945 static bool
6947 tsubst_flags_t complain)
6948 {
6964 {
6965 auto_diagnostic_group d;
6971 else
6973 }
6975 }
6977 /* Returns TRUE iff the address of OP is value-dependent.
6979 14.6.2.4 [temp.dep.temp]:
6980 A non-integral non-type template-argument is dependent if its type is
6981 dependent or it has either of the following forms
6982 qualified-id
6983 & qualified-id
6984 and contains a nested-name-specifier which specifies a class-name that
6985 names a dependent type.
6987 We generalize this to just say that the address of a member of a
6988 dependent class is value-dependent; the above doesn't cover the
6989 address of a static data member named with an unqualified-id. */
6991 static bool
6993 {
6996 /* We could use get_inner_reference here, but there's no need;
6997 this is only relevant for template non-type arguments, which
6998 can only be expressed as &id-expression. */
7000 {
7011 }
7014 }
7016 /* The next set of functions are used for providing helpful explanatory
7017 diagnostics for failed overload resolution. Their messages should be
7018 indented by two spaces for consistency with the messages in
7019 call.cc */
7021 static int
7023 {
7025 }
7027 /* Other failure functions should call this one, to provide a single function
7028 for setting a breakpoint on. */
7030 static int
7032 {
7034 }
7036 static int
7038 {
7043 }
7045 static int
7047 {
7053 }
7055 static int
7057 {
7061 }
7063 static int
7065 {
7068 " template parameter %qD is not a parameter pack, but "
7072 }
7074 static int
7076 {
7079 " template argument %qE does not match "
7083 }
7085 static int
7087 {
7091 }
7093 static int
7095 {
7101 }
7103 static int
7105 {
7107 {
7112 else
7114 " deduced conflicting values for non-type parameter "
7116 }
7118 }
7120 static int
7122 {
7125 " variable-sized array type %qT is not "
7127 arg);
7129 }
7131 static int
7133 {
7137 arg);
7139 }
7141 static int
7143 {
7145 {
7151 else
7156 }
7158 }
7160 static int
7162 {
7164 }
7166 static int
7169 {
7171 }
7173 static int
7176 {
7182 }
7184 static int
7187 {
7190 {
7198 }
7200 }
7202 static int
7204 {
7207 " template parameters of a template template argument are "
7210 }
7212 static int
7214 {
7220 }
7222 static int
7224 {
7229 }
7231 /* Subroutine of convert_nontype_argument, to check whether EXPR, as an
7232 argument for TYPE, points to an unsuitable object.
7234 Also adjust the type of the index in C++20 array subobject references. */
7236 static bool
7238 {
7240 {
7241 CASE_CONVERT:
7243 complain);
7247 complain);
7250 {
7254 }
7258 {
7264 {
7268 /* Canonicalize array offsets to ptrdiff_t; how they were
7269 written doesn't matter for subobject identity. */
7272 }
7275 {
7278 "%qE is not a valid template argument of type %qT "
7282 }
7284 {
7287 "%qE is not a valid template argument of type %qT "
7291 }
7294 {
7297 "%qE is not a valid template argument of type %qT "
7300 }
7301 /* C++17: For a non-type template-parameter of reference or pointer
7302 type, the value of the constant expression shall not refer to (or
7303 for a pointer type, shall not be the address of):
7304 * a subobject (4.5),
7305 * a temporary object (15.2),
7306 * a string literal (5.13.5),
7307 * the result of a typeid expression (8.2.8), or
7308 * a predefined __func__ variable (11.4.1). */
7311 {
7315 decl);
7317 }
7319 && !(same_type_ignoring_top_level_qualifiers_p
7322 {
7327 }
7329 {
7333 decl);
7335 }
7336 }
7344 else
7345 {
7347 {
7350 "because %qD is a variable, not the address of "
7353 }
7354 else
7355 {
7361 }
7362 }
7363 }
7366 }
7368 /* Return a VAR_DECL for the C++20 template parameter object corresponding to
7369 template argument EXPR. */
7371 static tree
7373 {
7379 {
7384 }
7388 /* This is no longer a compound literal. */
7392 }
7394 /* The template arguments corresponding to template parameter objects of types
7395 that contain pointers to members. */
7399 /* Find or build an nttp object for (already-validated) EXPR with name
7400 NAME. When CHECK_INIT is false we don't need to process the initialiser,
7401 it's already been done. */
7403 tree
7405 {
7422 {
7423 /* If EXPR contains any PTRMEM_CST, they will get clobbered by
7424 lower_var_init before we're done mangling. So store the original
7425 value elsewhere. We only need to unshare EXPR if it's not yet
7426 been processed. */
7429 }
7432 {
7433 /* The EXPR is the already processed initializer, set it on the NTTP
7434 object now so that cp_finish_decl doesn't do it again later. */
7437 }
7442 }
7444 /* Return the actual template argument corresponding to template parameter
7445 object VAR. */
7447 tree
7449 {
7453 }
7455 /* Attempt to convert the non-type template parameter EXPR to the
7456 indicated TYPE. If the conversion is successful, return the
7457 converted value. If the conversion is unsuccessful, return
7458 NULL_TREE if we issued an error message, or error_mark_node if we
7459 did not. We issue error messages for out-and-out bad template
7460 parameters, but not simply because the conversion failed, since we
7461 might be just trying to do argument deduction. Both TYPE and EXPR
7462 must be non-dependent.
7464 The conversion follows the special rules described in
7465 [temp.arg.nontype], and it is much more strict than an implicit
7466 conversion.
7468 This function is called twice for each template argument (see
7469 lookup_template_class for a more accurate description of this
7470 problem). This means that we need to handle expressions which
7471 are not valid in a C++ source, but can be created from the
7472 first call (for instance, casts to perform conversions). These
7473 hacks can go away after we fix the double coercion problem. */
7475 static tree
7477 {
7478 tree expr_type;
7481 /* Detect immediately string literals as invalid non-type argument.
7482 This special-case is not needed for correctness (we would easily
7483 catch this later), but only to provide better diagnostic for this
7484 common user mistake. As suggested by DR 100, we do not mention
7485 linkage issues in the diagnostic as this is not the point. */
7487 {
7493 }
7495 /* Add the ADDR_EXPR now for the benefit of
7496 value_dependent_expression_p. */
7499 {
7503 }
7505 /* If we are in a template, EXPR may be non-dependent, but still
7506 have a syntactic, rather than semantic, form. For example, EXPR
7507 might be a SCOPE_REF, rather than the VAR_DECL to which the
7508 SCOPE_REF refers. Preserving the qualifying scope is necessary
7509 so that access checking can be performed when the template is
7510 instantiated -- but here we need the resolved form so that we can
7511 convert the argument. */
7523 /* If the argument is non-dependent, perform any conversions in
7524 non-dependent context as well. */
7532 else
7535 /* 14.3.2/5: The null pointer{,-to-member} conversion is applied
7536 to a non-type argument of "nullptr". */
7540 /* In C++11, integral or enumeration non-type template arguments can be
7541 arbitrary constant expressions. Pointer and pointer to
7542 member arguments can be general constant expressions that evaluate
7543 to a null value, but otherwise still need to be of a specific form. */
7545 {
7547 /* A PTRMEM_CST is already constant, and a valid template
7548 argument for a parameter of pointer to member type, we just want
7549 to leave it in that form rather than lower it to a
7553 {
7554 /* C++17: A template-argument for a non-type template-parameter shall
7555 be a converted constant expression (8.20) of the type of the
7556 template-parameter. */
7559 /* Make sure we return NULL_TREE only if we have really issued
7560 an error, as described above. */
7563 {
7566 }
7569 /* EXPR may have become value-dependent. */
7571 }
7573 {
7578 }
7579 }
7583 else
7586 /* HACK: Due to double coercion, we can get a
7587 NOP_EXPR<REFERENCE_TYPE>(ADDR_EXPR<POINTER_TYPE> (arg)) here,
7588 which is the tree that we built on the first call (see
7589 below when coercing to reference to object or to reference to
7590 function). We just strip everything and get to the arg.
7591 See g++.old-deja/g++.oliva/template4.C and g++.dg/template/nontype9.C
7592 for examples. */
7594 {
7595 /* Check this before we strip *& to avoid redundancy. */
7604 {
7605 /* ??? Maybe we could use convert_from_reference here, but we
7606 would need to relax its constraints because the NOP_EXPR
7607 could actually change the type to something more cv-qualified,
7608 and this is not folded by convert_from_reference. */
7613 && (same_type_ignoring_top_level_qualifiers_p
7616 {
7619 }
7620 }
7621 }
7623 /* [temp.arg.nontype]/5, bullet 1
7625 For a non-type template-parameter of integral or enumeration type,
7626 integral promotions (_conv.prom_) and integral conversions
7627 (_conv.integral_) are applied. */
7630 {
7632 {
7637 }
7642 /* Notice that there are constant expressions like '4 % 0' which
7643 do not fold into integer constants. */
7645 {
7647 {
7651 else
7657 /* else cxx_constant_value complained but gave us
7658 a real constant, so go ahead. */
7660 {
7661 /* Some assemble time constant expressions like
7662 (intptr_t)&&lab1 - (intptr_t)&&lab2 or
7663 4 + (intptr_t)&&var satisfy reduced_constant_expression_p
7664 as we can emit them into .rodata initializers of
7665 variables, yet they can't fold into an INTEGER_CST at
7666 compile time. Refuse them here. */
7671 }
7672 }
7673 else
7675 }
7677 /* Avoid typedef problems. */
7680 }
7681 /* [temp.arg.nontype]/5, bullet 2
7683 For a non-type template-parameter of type pointer to object,
7684 qualification conversions (_conv.qual_) and the array-to-pointer
7685 conversion (_conv.array_) are applied. */
7687 {
7690 /* Look through any NOP_EXPRs around an ADDR_EXPR, whether they come from
7691 decay_conversion or an explicit cast. If it's a problematic cast,
7692 we'll complain about it below. */
7694 {
7699 {
7702 }
7703 }
7705 /* [temp.arg.nontype]/1 (TC1 version, DR 49):
7707 A template-argument for a non-type, non-template template-parameter
7708 shall be one of: [...]
7710 -- the name of a non-type template-parameter;
7711 -- the address of an object or function with external linkage, [...]
7712 expressed as "& id-expression" where the & is optional if the name
7713 refers to a function or array, or if the corresponding
7714 template-parameter is a reference.
7716 Here, we do not care about functions, as they are invalid anyway
7717 for a parameter of type pointer-to-object. */
7720 /* Non-type template parameters are OK. */
7721 ;
7726 /* Other values, like integer constants, might be valid
7727 non-type arguments of some other type. */
7737 }
7738 /* [temp.arg.nontype]/5, bullet 3
7740 For a non-type template-parameter of type reference to object, no
7741 conversions apply. The type referred to by the reference may be more
7742 cv-qualified than the (otherwise identical) type of the
7743 template-argument. The template-parameter is bound directly to the
7744 template-argument, which must be an lvalue. */
7746 {
7748 expr_type))
7752 {
7757 }
7760 {
7765 }
7767 /* [temp.arg.nontype]/1
7769 A template-argument for a non-type, non-template template-parameter
7770 shall be one of: [...]
7772 -- the address of an object or function with external linkage. */
7775 {
7778 {
7781 "because a reference variable does not have a constant "
7784 }
7785 }
7788 /* OK, dependent reference. We don't want to ask whether a DECL is
7790 else
7791 {
7796 }
7800 }
7801 /* [temp.arg.nontype]/5, bullet 4
7803 For a non-type template-parameter of type pointer to function, only
7804 the function-to-pointer conversion (_conv.func_) is applied. If the
7805 template-argument represents a set of overloaded functions (or a
7806 pointer to such), the matching function is selected from the set
7807 (_over.over_). */
7809 {
7810 /* If the argument is a template-id, we might not have enough
7811 context information to decay the pointer. */
7813 {
7817 }
7820 /* Null pointer values are OK in C++11. */
7826 }
7827 /* [temp.arg.nontype]/5, bullet 5
7829 For a non-type template-parameter of type reference to function, no
7830 conversions apply. If the template-argument represents a set of
7831 overloaded functions, the matching function is selected from the set
7832 (_over.over_). */
7834 {
7836 {
7838 {
7839 auto_diagnostic_group d;
7844 }
7846 }
7851 }
7852 /* [temp.arg.nontype]/5, bullet 6
7854 For a non-type template-parameter of type pointer to member function,
7855 no conversions apply. If the template-argument represents a set of
7856 overloaded member functions, the matching member function is selected
7857 from the set (_over.over_). */
7859 {
7864 /* [temp.arg.nontype] bullet 1 says the pointer to member
7865 expression must be a pointer-to-member constant. */
7870 /* Repeated conversion can't deal with a conversion that turns PTRMEM_CST
7871 into a CONSTRUCTOR, so build up a new PTRMEM_CST instead. */
7874 }
7875 /* [temp.arg.nontype]/5, bullet 7
7877 For a non-type template-parameter of type pointer to data member,
7878 qualification conversions (_conv.qual_) are applied. */
7880 {
7881 /* [temp.arg.nontype] bullet 1 says the pointer to member
7882 expression must be a pointer-to-member constant. */
7890 }
7892 {
7894 {
7899 }
7901 }
7903 {
7904 /* Replace the argument with a reference to the corresponding template
7905 parameter object. */
7910 }
7911 /* A template non-type parameter must be one of the above. */
7912 else
7915 /* Sanity check: did we actually convert the argument to the
7916 right type? */
7920 }
7922 /* Subroutine of coerce_template_template_parms, which returns true if
7923 PARM and ARG match using the rule for the template parameters of
7924 template template parameters. Both PARM and ARG are template parameters;
7925 the rest of the arguments are the same as for
7926 coerce_template_template_parms. */
7928 static bool
7931 {
7940 {
7942 /* We encounter instantiations of templates like
7943 template <template <template <class> class> class TT>
7944 class C; */
7945 {
7949 }
7950 /* Fall through. */
7955 /* Argument is a parameter pack but parameter is not. */
7960 /* The tsubst call is used to handle cases such as
7962 template <int> class C {};
7963 template <class T, template <T> class TT> class D {};
7964 D<int, C> d;
7966 i.e. the parameter list of TT depends on earlier parameters. */
7968 {
7975 }
7979 /* Argument is a parameter pack but parameter is not. */
7986 }
7989 }
7991 /* Coerce template argument list ARGLIST for use with template
7992 template-parameter TEMPL. */
7994 static tree
7996 tsubst_flags_t complain)
7997 {
7998 /* Consider an example where a template template parameter declared as
8000 template <class T, class U = std::allocator<T> > class TT
8002 The template parameter level of T and U are one level larger than
8003 of TT. To proper process the default argument of U, say when an
8004 instantiation `TT<int>' is seen, we need to build the full
8005 arguments containing {int} as the innermost level. Outer levels,
8006 available when not appearing as default template argument, can be
8007 obtained from the arguments of the enclosing template.
8009 Suppose that TT is later substituted with std::vector. The above
8010 instantiation is `TT<int, std::allocator<T> >' with TT at
8011 level 1, and T at level 2, while the template arguments at level 1
8012 becomes {std::vector} and the inner level 2 is {int}. */
8018 {
8019 /* This is an argument of the current template, so we haven't set
8020 DECL_CONTEXT yet. We can also get here when level-lowering a
8021 bound ttp. */
8022 tree relevant_template_parms;
8024 /* Parameter levels that are greater than the level of the given
8025 template template parm are irrelevant. */
8032 }
8039 }
8041 /* A cache of template template parameters with match-all default
8042 arguments. */
8045 /* T is a bound template template-parameter. Copy its arguments into default
8046 arguments of the template template-parameter's template parameters. */
8048 static tree
8050 {
8073 {
8076 {
8079 }
8080 }
8084 tree gen_ntmpl;
8087 else
8097 }
8099 /* ARG is a bound potential template template-argument, and PARGS is a list
8100 of arguments for the corresponding template template-parameter. Adjust
8101 PARGS as appropriate for application to ARG's template, and if ARG is a
8102 BOUND_TEMPLATE_TEMPLATE_PARM, possibly adjust it to add default template
8103 arguments to the template template parameter. */
8105 static tree
8107 {
8111 {
8112 /* When comparing two template template-parameters in partial ordering,
8113 rewrite the one currently being used as an argument to have default
8114 arguments for all parameters. */
8120 }
8121 else
8122 {
8123 tree aparms
8126 }
8129 }
8131 /* Subroutine of unify for the case when PARM is a
8132 BOUND_TEMPLATE_TEMPLATE_PARM. */
8134 static int
8137 {
8141 /* The template template parm might be variadic and the argument
8142 not, so flatten both argument lists. */
8147 {
8148 /* In keeping with P0522R0, adjust P's template arguments
8149 to apply to A's template; then flatten it again. */
8157 /* If the P0522 adjustment eliminated a pack expansion, deduce
8158 empty packs. */
8164 }
8165 else
8166 {
8167 /* Deduce arguments T, i from TT<T> or TT<i>.
8168 We check each element of PARMVEC and ARGVEC individually
8169 rather than the whole TREE_VEC since they can have
8170 different number of elements, which is allowed under N2555. */
8174 /* Check if the parameters end in a pack, making them
8175 variadic. */
8182 /* If the template argument list of P contains a pack
8183 expansion that is not the last template argument, the
8184 entire template argument list is a non-deduced
8185 context. */
8203 DEDUCE_EXACT,
8206 }
8209 }
8211 /* Return 1 if PARM_TMPL and ARG_TMPL match using rule for
8212 template template parameters.
8214 Consider the example:
8215 template <class T> class A;
8216 template<template <class U> class TT> class B;
8218 For B<A>, PARM_TMPL is TT, while ARG_TMPL is A,
8219 and OUTER_ARGS contains A. */
8221 static int
8223 tree arg_tmpl,
8224 tsubst_flags_t complain,
8225 tree in_decl,
8226 tree outer_args)
8227 {
8241 {
8242 /* P0522R0: A template template-parameter P is at least as specialized as
8243 a template template-argument A if, given the following rewrite to two
8244 function templates, the function template corresponding to P is at
8245 least as specialized as the function template corresponding to A
8246 according to the partial ordering rules for function templates
8247 ([temp.func.order]). Given an invented class template X with the
8248 template parameter list of A (including default arguments):
8250 * Each of the two function templates has the same template parameters,
8251 respectively, as P or A.
8253 * Each function template has a single function parameter whose type is
8254 a specialization of X with template arguments corresponding to the
8255 template parameters from the respective function template where, for
8256 each template parameter PP in the template parameter list of the
8257 function template, a corresponding template argument AA is formed. If
8258 PP declares a parameter pack, then AA is the pack expansion
8259 PP... ([temp.variadic]); otherwise, AA is the id-expression PP.
8261 If the rewrite produces an invalid type, then P is not at least as
8262 specialized as A. */
8264 /* So coerce P's args to apply to A's parms, and then deduce between A's
8265 args and the converted args. If that succeeds, A is at least as
8266 specialized as P, so they match.*/
8272 /* PARM and ARG might be at different template depths, and we want to
8273 pass the right additional levels of args when coercing PARGS to
8274 ARG_PARMS in case we need to do any substitution into non-type
8275 template parameter types.
8277 OUTER_ARGS are not the right outer levels in this case, as they are
8278 the args we're building up for PARM, and for the coercion we want the
8279 args for ARG. If DECL_CONTEXT isn't set for a template template
8280 parameter, we can assume that it's in the current scope. */
8288 {
8293 /* Only use as many levels from the scope as needed
8294 (excluding the level of ARG). */
8298 else
8301 /* Add the arguments that appear at the levels of ARG. */
8308 }
8309 else
8315 {
8321 }
8322 }
8324 /* Determine whether we have a parameter pack at the end of the
8325 template template parameter's template parameter list. */
8327 {
8334 {
8348 }
8349 }
8355 /* Check all of the template parameters except the parameter pack at
8356 the end (if any). */
8358 {
8367 outer_args))
8370 }
8373 {
8374 /* Check each of the template parameters in the template
8375 argument against the template parameter pack at the end of
8376 the template template parameter. */
8383 {
8390 outer_args))
8392 }
8393 }
8396 }
8398 /* Verifies that the deduced template arguments (in TARGS) for the
8399 template template parameters (in TPARMS) represent valid bindings,
8400 by comparing the template parameter list of each template argument
8401 to the template parameter list of its corresponding template
8402 template parameter, in accordance with DR150. This
8403 routine can only be called after all template arguments have been
8404 deduced. It will return TRUE if all of the template template
8405 parameter bindings are okay, FALSE otherwise. */
8406 bool
8408 {
8412 /* We're dealing with template parms in this process. */
8418 {
8423 {
8428 {
8429 /* Look inside the argument pack. */
8432 }
8435 {
8437 /* Extract the next argument from the argument
8438 pack. */
8442 /* Look at the pattern of the pack expansion. */
8445 /* Extract the template parameters from the template
8446 argument. */
8450 /* Verify that we can coerce the template template
8451 parameters from the template argument to the template
8452 parameter. This requires an exact match. */
8454 && !coerce_template_template_parms
8456 targ,
8457 tf_none,
8458 tparm,
8459 targs))
8460 {
8463 }
8464 }
8465 }
8466 }
8468 out:
8472 }
8474 /* Since type attributes aren't mangled, we need to strip them from
8475 template type arguments. */
8477 tree
8479 {
8489 }
8491 /* And from inside dependent non-type arguments like sizeof(Type). */
8493 static tree
8495 {
8505 }
8507 /* A template declaration can be substituted for a constrained
8508 template template parameter only when the argument is no more
8509 constrained than the parameter. */
8511 static bool
8513 {
8516 /* For now, allow constrained template template arguments
8517 and unconstrained template template parameters. */
8521 /* If the template parameter is constrained, we need to rewrite its
8522 constraints in terms of the ARG's template parameters. This ensures
8523 that all of the template parameter types will have the same depth.
8525 Note that this is only valid when coerce_template_template_parm is
8526 true for the innermost template parameters of PARM and ARG. In other
8527 words, because coercion is successful, this conversion will be valid. */
8530 {
8540 }
8543 }
8545 // Convert a placeholder argument into a binding to the original
8546 // parameter. The original parameter is saved as the TREE_TYPE of
8547 // ARG.
8550 {
8553 }
8555 /* We can't fully resolve ARG given as a non-type template argument to TYPE,
8556 because one of them is dependent. But we need to represent the
8557 conversion for the benefit of cp_tree_equal. */
8559 static tree
8561 {
8562 /* Auto parms get no conversion. */
8565 /* ??? Do we need to push the IMPLICIT_CONV_EXPR into the pack expansion?
8566 That would complicate other things, and it doesn't seem necessary. */
8569 /* We don't need or want to add this conversion now if we're going to use the
8570 argument for deduction. */
8585 }
8587 /* Convert the indicated template ARG as necessary to match the
8588 indicated template PARM. Returns the converted ARG, or
8589 error_mark_node if the conversion was unsuccessful. Error and
8590 warning messages are issued under control of COMPLAIN. This
8591 conversion is for the Ith parameter in the parameter list. ARGS is
8592 the full set of template arguments deduced so far. */
8594 static tree
8596 tree arg,
8597 tree args,
8598 tsubst_flags_t complain,
8600 tree in_decl)
8601 {
8602 tree orig_arg;
8603 tree val;
8609 /* Trivially convert placeholders. */
8618 {
8619 /* The template argument was the name of some
8620 member function. That's usually
8621 invalid, but static members are OK. In any
8622 case, grab the underlying fields/functions
8623 and issue an error later if required. */
8625 }
8633 /* When determining whether an argument pack expansion is a template,
8634 look at the pattern. */
8638 /* Deal with an injected-class-name used as a template template arg. */
8640 {
8643 {
8653 }
8654 }
8656 is_tmpl_type =
8672 {
8674 {
8678 }
8681 "to refer to a type member of a template parameter, "
8686 typename_type,
8687 complain);
8690 }
8692 {
8694 {
8696 {
8697 auto_diagnostic_group d;
8702 {
8703 /* The template argument is a type, but we're expecting
8704 an expression. */
8709 /* [temp.arg]/2: "In a template-argument, an ambiguity
8710 between a type-id and an expression is resolved to a
8711 type-id, regardless of the form of the corresponding
8712 template-parameter." So give the user a clue. */
8715 "for non-type template parameter is treated as "
8717 }
8721 else
8724 }
8725 }
8727 }
8729 {
8731 {
8732 auto_diagnostic_group d;
8739 else
8742 }
8744 }
8747 /* We already did the appropriate conversion when packing args. */
8750 {
8752 {
8754 /* The number of argument required is not known yet.
8755 Just accept it for now. */
8757 else
8758 {
8759 /* Strip alias templates that are equivalent to another
8760 template. */
8765 args))
8766 {
8769 /* TEMPLATE_TEMPLATE_PARM node is preferred over
8770 TEMPLATE_DECL. */
8772 {
8777 }
8778 }
8779 else
8780 {
8782 {
8783 auto_diagnostic_group d;
8790 }
8793 }
8795 // Check that the constraints are compatible before allowing the
8796 // substitution.
8799 {
8801 {
8802 auto_diagnostic_group d;
8808 }
8810 }
8811 }
8812 }
8813 else
8815 /* We only form one instance of each template specialization.
8816 Therefore, if we use a non-canonical variant (i.e., a
8817 typedef), any future messages referring to the type will use
8818 the typedef, which is confusing if those future uses do not
8819 themselves also use the typedef. */
8822 }
8823 else
8824 {
8829 /* We don't have enough levels of args to do any substitution. This
8832 {
8837 }
8838 else
8841 /* Perform array-to-pointer and function-to-pointer conversion
8842 as per [temp.param]/10. */
8848 /* Drop top-level cv-qualifiers on the substituted/deduced type of
8849 this non-type template parameter, as per [temp.param]/6. */
8855 /* We need to handle arguments for alias or concept templates
8856 differently: we need to force building an IMPLICIT_CONV_EXPR, because
8857 these arguments are going to be substituted directly into the
8858 dependent type; they might not get another chance at
8859 convert_nontype_argument. But if the argument ends up here again for
8860 a template that isn't one of those, remove the conversion for
8861 consistency between naming the same dependent type directly or through
8862 an alias. */
8873 /* We used to call digest_init here. However, digest_init
8874 will report errors, which we don't want when complain
8875 is zero. More importantly, digest_init will try too
8876 hard to convert things: for example, `0' should not be
8877 converted to pointer type at this point according to
8878 the standard. Accepting this is not merely an
8879 extension, since deciding whether or not these
8880 conversions can occur is part of determining which
8881 function template to call, or whether a given explicit
8882 argument specification is valid. */
8884 else
8885 {
8888 }
8898 {
8899 /* Reject template arguments that are references to built-in
8900 functions with no library fallbacks. */
8909 }
8912 {
8913 /* Strip typedefs from the SCOPE_REF. */
8916 complain);
8919 }
8920 }
8923 }
8925 /* Coerces the remaining template arguments in INNER_ARGS (from
8926 ARG_IDX to the end) into the parameter pack at PARM_IDX in PARMS.
8927 Returns the coerced argument pack. PARM_IDX is the position of this
8928 parameter in the template parameter list. ARGS is the original
8929 template argument list. */
8930 static tree
8933 tree args,
8934 tree inner_args,
8936 tree new_args,
8938 tree in_decl,
8939 tsubst_flags_t complain)
8940 {
8943 tree packed_args;
8944 tree argument_pack;
8951 {
8952 /* When the template parameter is a non-type template parameter pack
8953 or template template parameter pack whose type or template
8954 parameters use parameter packs, we know exactly how many arguments
8955 we are looking for. Build a vector of the instantiated decls for
8956 these template parameters in PACKED_PARMS. */
8957 /* We can't use make_pack_expansion here because it would interpret a
8958 _DECL as a use rather than a declaration. */
8972 /* If we're doing a partial instantiation of a member template,
8973 verify that all of the types used for the non-type
8974 template parameter pack are, in fact, valid for non-type
8975 template parameters. */
8978 {
8981 {
8986 }
8987 /* We don't know how many args we have yet, just
8988 use the unconverted ones for now. */
8990 }
8993 }
8994 /* Check if we have a placeholder pack, which indicates we're
8995 in the context of a introduction list. In that case we want
8996 to match this pack to the single placeholder. */
9000 {
9003 }
9004 else
9007 /* Convert the remaining arguments, which will be a part of the
9008 parameter pack "parm". */
9011 {
9017 {
9018 /* Once we've packed as many args as we have types, stop. */
9022 /* We don't know how many args we have yet, just
9023 use the unconverted ones for now. */
9025 else
9027 }
9030 {
9033 }
9034 else
9037 in_decl);
9041 }
9045 {
9050 }
9055 else
9056 {
9059 }
9066 }
9068 /* Returns the number of pack expansions in the template argument vector
9069 ARGS. */
9071 static int
9073 {
9078 {
9082 }
9084 }
9086 /* Convert all template arguments to their appropriate types, and
9087 return a vector containing the innermost resulting template
9088 arguments. If any error occurs, return error_mark_node. Error and
9089 warning messages are issued under control of COMPLAIN.
9091 If PARMS represents all template parameters levels, this function
9092 returns a vector of vectors representing all the resulting argument
9093 levels. Note that in this case, only the innermost arguments are
9094 coerced because the outermost ones are supposed to have been coerced
9095 already. Otherwise, if PARMS represents only (the innermost) vector
9096 of parameters, this function returns a vector containing just the
9097 innermost resulting arguments.
9099 If REQUIRE_ALL_ARGS is false, argument deduction will be performed
9100 for arguments not specified in ARGS. If REQUIRE_ALL_ARGS is true,
9101 arguments not specified in ARGS must have default arguments which
9102 we'll use to fill in ARGS. */
9104 tree
9106 tree args,
9107 tree in_decl,
9108 tsubst_flags_t complain,
9110 {
9112 tree orig_inner_args;
9113 tree inner_args;
9115 /* When used as a boolean value, indicates whether this is a
9116 variadic template parameter list. Since it's an int, we can also
9117 subtract it from nparms to get the number of non-variadic
9118 parameters. */
9123 /* Adjustment to nparms for fixed parameter packs. */
9128 /* Likewise for parameters with default arguments. */
9136 {
9138 {
9141 }
9143 }
9147 /* Determine if there are any parameter packs or default arguments. */
9149 {
9157 }
9160 /* If there are no parameters that follow a parameter pack, we need to
9161 expand any argument packs so that we can deduce a parameter pack from
9162 some non-packed args followed by an argument pack, as in variadic85.C.
9163 If there are such parameters, we need to leave argument packs intact
9164 so the arguments are assigned properly. This can happen when dealing
9165 with a nested class inside a partial specialization of a class
9166 template, as in variadic92.C, or when deducing a template parameter pack
9167 from a sub-declarator, as in variadic114.C. */
9171 /* Count any pack expansion args. */
9177 && require_all_args
9178 && !variadic_args_p
9181 {
9182 bad_nargs:
9184 {
9185 auto_diagnostic_group d;
9187 {
9191 }
9192 else
9199 }
9202 }
9203 /* We can't pass a pack expansion to a non-pack parameter of an alias
9204 template (DR 1430). */
9208 && variadic_args_p
9210 {
9212 {
9214 {
9220 {
9221 auto_diagnostic_group d;
9224 "pack expansion argument for non-pack parameter "
9226 else
9228 "pack expansion argument for non-pack parameter "
9232 }
9233 }
9235 found:;
9236 }
9238 }
9240 /* We need to evaluate the template arguments, even though this
9241 template-id may be nested within a "sizeof". */
9242 cp_evaluated ev;
9248 {
9249 tree arg;
9250 tree parm;
9252 /* Get the Ith template parameter. */
9256 {
9259 }
9261 /* Calculate the next argument. */
9264 else
9270 {
9271 /* Some arguments will be placed in the
9272 template parameter pack PARM. */
9279 {
9280 /* We don't know how many args we have yet, just use the
9281 unconverted (and still packed) ones for now. */
9286 }
9290 /* Store this argument. */
9292 {
9293 lost++;
9294 /* We are done with all of the arguments. */
9297 }
9298 else
9299 {
9303 {
9306 }
9307 }
9310 }
9312 {
9314 {
9315 /* "If every valid specialization of a variadic template
9316 requires an empty template parameter pack, the template is
9317 ill-formed, no diagnostic required." So check that the
9318 pattern works with this parameter. */
9323 in_decl);
9325 {
9330 }
9332 /* Recover from missing typename. */
9336 /* We don't know how many args we have yet, just
9337 use the unconverted (but unpacked) ones for now. */
9342 }
9343 }
9345 {
9346 /* There must be a default arg in this case. */
9348 complain | (processing_template_decl
9350 in_decl);
9351 /* The position of the first default template argument,
9352 is also the number of non-defaulted arguments in NEW_INNER_ARGS.
9353 Record that. */
9357 }
9358 else
9362 {
9365 }
9367 {
9368 /* This can occur if there was an error in the template
9369 parameter list itself (which we would already have
9370 reported) that we are trying to recover from, e.g., a class
9371 template with a parameter list such as
9372 template<typename..., typename> (cpp0x/variadic150.C). */
9375 /* This can also happen with a fixed parameter pack (71834). */
9378 }
9379 else
9385 lost++;
9388 }
9391 {
9392 /* If we had fixed parameter packs, we didn't know how many arguments we
9393 actually needed earlier; now we do. */
9397 }
9400 {
9401 /* We had some pack expansion arguments that will only work if the packs
9402 are empty, but wait until instantiation time to complain.
9403 See variadic-ttp3.C. */
9405 /* Except that we can't provide empty packs to alias templates or
9406 concepts when there are no corresponding parameters. Basically,
9407 we can get here with this:
9409 template<typename T> concept C = true;
9411 template<typename... Args>
9412 requires C<Args...>
9413 void f();
9415 When parsing C<Args...>, we try to form a concept check of
9416 C<?, Args...>. Without the extra check for substituting an empty
9417 pack past the last parameter, we can accept the check as valid.
9419 FIXME: This may be valid for alias templates (but I doubt it).
9421 FIXME: The error could be better also. */
9423 {
9428 }
9439 }
9442 {
9445 }
9451 /* If we expanded packs in inner_args and aren't returning it now, the
9452 expanded vec is garbage. */
9458 }
9460 /* Returns true if T is a wrapper to make a C++20 template parameter
9461 object const. */
9463 static bool
9465 {
9471 }
9473 /* Returns 1 if template args OT and NT are equivalent. */
9475 int
9477 {
9490 /* DR 1558: Don't treat an alias template specialization with dependent
9491 arguments as equivalent to its underlying type when used as a template
9492 argument; we need them to be distinct so that we substitute into the
9493 specialization arguments at instantiation time. And aliases can't be
9494 equivalent without being ==, so we don't need to look any deeper.
9496 During partial ordering, however, we need to treat them normally so we can
9497 order uses of the same alias with different cv-qualification (79960). */
9503 /* For member templates */
9516 {
9520 }
9521 else
9522 {
9523 /* Try to treat a template non-type argument that has been converted
9524 to the parameter type as equivalent to one that hasn't yet. */
9538 }
9539 }
9541 /* Returns true iff the OLDARGS and NEWARGS are in fact identical sets of
9542 template arguments. Returns false otherwise, and updates OLDARG_PTR and
9543 NEWARG_PTR with the offending arguments if they are non-NULL. */
9545 bool
9548 {
9559 {
9564 {
9570 }
9571 }
9573 }
9575 static bool
9577 {
9582 }
9584 /* Implement a freelist interface for objects of type T.
9586 Head is a separate object, rather than a regular member, so that we
9587 can define it as a GTY deletable pointer, which is highly
9588 desirable. A data member could be declared that way, but then the
9589 containing object would implicitly get GTY((user)), which would
9590 prevent us from instantiating freelists as global objects.
9591 Although this way we can create freelist global objects, they're
9592 such thin wrappers that instantiating temporaries at every use
9593 loses nothing and saves permanent storage for the freelist object.
9595 Member functions next, anew, poison and reinit have default
9596 implementations that work for most of the types we're interested
9597 in, but if they don't work for some type, they should be explicitly
9598 specialized. See the comments before them for requirements, and
9599 the example specializations for the tree_list_freelist. */
9601 class freelist
9602 {
9603 /* Return the next object in a chain. We could just do type
9604 punning, but if we access the object with its underlying type, we
9605 avoid strict-aliasing trouble. This needs only work between
9606 poison and reinit. */
9609 /* Return a newly allocated, uninitialized or minimally-initialized
9610 object of type T. Any initialization performed by anew should
9611 either remain across the life of the object and the execution of
9612 poison, or be redone by reinit. */
9615 /* Optionally scribble all over the bits holding the object, so that
9616 they become (mostly?) uninitialized memory. This is called while
9617 preparing to make the object part of the free list. */
9622 #ifdef ENABLE_GC_CHECKING
9623 /* Poison the data, to indicate the data is garbage. */
9626 #endif
9627 /* Let valgrind know the object is free. */
9630 /* Let valgrind know the next portion of the object is available,
9631 but uninitialized. */
9633 }
9635 /* Bring an object that underwent at least one lifecycle after anew
9636 and before the most recent free and poison, back to a usable
9637 state, reinitializing whatever is needed for it to be
9638 functionally equivalent to an object just allocated and returned
9639 by anew. This may poison or clear the next field, used by
9640 freelist housekeeping after poison was called. */
9644 #ifdef ENABLE_GC_CHECKING
9646 #endif
9647 /* Let valgrind know the entire object is available, but
9648 uninitialized. */
9650 }
9652 /* Reference a GTY-deletable pointer that points to the first object
9653 in the free list proper. */
9656 /* Construct a freelist object chaining objects off of HEAD. */
9659 /* Add OBJ to the free object list. The former head becomes OBJ's
9660 successor. */
9662 {
9666 }
9668 /* Take an object from the free list, if one is available, or
9669 allocate a new one. Objects taken from the free list should be
9670 regarded as filled with garbage, except for bits that are
9671 configured to be preserved across free and alloc. */
9673 {
9675 {
9680 }
9681 else
9683 }
9684 };
9686 /* Explicitly specialize the interfaces for freelist<tree_node>: we
9687 want to allocate a TREE_LIST using the usual interface, and ensure
9688 TREE_CHAIN remains functional. Alas, we have to duplicate a bit of
9689 build_tree_list logic in reinit, so this could go out of sync. */
9693 {
9695 }
9697 inline tree
9699 {
9701 }
9705 {
9711 #ifdef ENABLE_GC_CHECKING
9714 /* Poison the data, to indicate the data is garbage. */
9717 #endif
9718 /* Let valgrind know the object is free. */
9720 /* But we still want to use the TREE_CODE and TREE_CHAIN parts. */
9724 #ifdef ENABLE_GC_CHECKING
9726 /* Keep TREE_CHAIN functional. */
9728 #else
9730 #endif
9731 }
9735 {
9738 #ifdef ENABLE_GC_CHECKING
9742 #endif
9744 /* Let valgrind know the entire object is available, but
9745 uninitialized. */
9748 #ifdef ENABLE_GC_CHECKING
9750 #else
9753 #endif
9755 }
9757 /* Point to the first object in the TREE_LIST freelist. */
9759 /* Return the/an actual TREE_LIST freelist. */
9762 {
9764 }
9766 /* Point to the first object in the tinst_level freelist. */
9768 /* Return the/an actual tinst_level freelist. */
9771 {
9773 }
9775 /* Point to the first object in the pending_template freelist. */
9777 /* Return the/an actual pending_template freelist. */
9780 {
9782 }
9784 /* Build the TREE_LIST object out of a split list, store it
9785 permanently, and return it. */
9786 tree
9788 {
9797 }
9801 /* Increment OBJ's refcount unless it is already infinite. */
9804 {
9808 }
9810 /* Release storage for OBJ and node, if it's a TREE_LIST. */
9811 void
9813 {
9817 }
9819 /* Decrement OBJ's refcount if not infinite. If it reaches zero, release
9820 OBJ's DECL and OBJ, and start over with the tinst_level object that
9821 used to be referenced by OBJ's NEXT. */
9822 static void
9824 {
9828 {
9832 }
9833 }
9835 /* Modify PTR so that it points to OBJ, adjusting the refcounts of OBJ
9836 and of the former PTR. Omitting the second argument is equivalent
9837 to passing (T*)NULL; this is allowed because passing the
9838 zero-valued integral constant NULL confuses type deduction and/or
9839 overload resolution. */
9841 static void
9843 {
9847 }
9849 static void
9851 {
9861 /* We are called both from instantiate_decl, where we've already had a
9862 tinst_level pushed, and instantiate_template, where we haven't.
9863 Compensate. */
9865 level = !current_tinst_level
9877 else
9886 }
9889 /* Return a TEMPLATE_ID_EXPR corresponding to the indicated FNS and
9890 ARGLIST. Valid choices for FNS are given in the cp-tree.def
9891 documentation for TEMPLATE_ID_EXPR. */
9893 tree
9895 {
9902 {
9905 }
9908 {
9911 unknown_type_node,
9913 arglist);
9915 }
9918 }
9920 /* Within the scope of a template class S<T>, the name S gets bound
9921 (in build_self_reference) to a TYPE_DECL for the class, not a
9922 TEMPLATE_DECL. If DECL is a TYPE_DECL for current_class_type,
9923 or one of its enclosing classes, and that type is a template,
9924 return the associated TEMPLATE_DECL. Otherwise, the original
9925 DECL is returned.
9927 Also handle the case when DECL is a TREE_LIST of ambiguous
9928 injected-class-names from different bases. */
9930 tree
9932 {
9936 /* DR 176: A lookup that finds an injected-class-name (10.2
9937 [class.member.lookup]) can result in an ambiguity in certain cases
9938 (for example, if it is found in more than one base class). If all of
9939 the injected-class-names that are found refer to specializations of
9940 the same class template, and if the name is followed by a
9941 template-argument-list, the reference refers to the class template
9942 itself and not a specialization thereof, and is not ambiguous. */
9944 {
9947 {
9953 }
9956 else
9958 }
9964 }
9966 /* If TYPE is the generic implicit instantiation A<T>, return the primary
9967 template type A<T> (which is suitable for entering into, e.g. for defining
9968 a member of A<T>), otherwise return TYPE. */
9970 tree
9972 {
9976 /* We detect the generic implicit instantiation A<T> by inspecting
9977 TYPE_CANONICAL, which lookup_template_class sets to the primary
9978 template type A<T>. */
9983 }
9985 /* Convenience wrapper over tsubst that does adjust_type_for_entering_scope
9986 on the result. */
9988 static tree
9990 {
9993 }
9995 /* Given an IDENTIFIER_NODE (or type TEMPLATE_DECL) and a chain of
9996 parameters, find the desired type.
9998 D1 is the PTYPENAME terminal, and ARGLIST is the list of arguments.
10000 IN_DECL, if non-NULL, is the template declaration we are trying to
10001 instantiate.
10003 Issue error and warning messages under control of COMPLAIN.
10005 If the template class is really a local class in a template
10006 function, then the FUNCTION_CONTEXT is the function in which it is
10007 being instantiated.
10009 ??? Note that this function is currently called *twice* for each
10010 template-id: the first time from the parser, while creating the
10011 incomplete type (finish_template_type), and the second type during the
10012 real instantiation (instantiate_template_class). This is surely something
10013 that we want to avoid. It also causes some problems with argument
10014 coercion (see convert_nontype_argument for more information on this). */
10016 tree
10018 tsubst_flags_t complain)
10019 {
10023 tree t;
10028 {
10032 else
10033 {
10040 }
10041 }
10043 {
10046 /* If we are declaring a constructor, say A<T>::A<T>, we will get
10047 an implicit typename for the second A. Deal with it. */
10052 {
10055 }
10056 }
10059 {
10062 }
10064 {
10067 }
10069 {
10072 }
10074 /* Issue an error message if we didn't find a template. */
10076 {
10080 }
10083 /* Make sure it's a user visible template, if it was named by
10084 the user. */
10087 {
10089 {
10093 }
10095 }
10099 /* An alias that just changes the name of a template is equivalent to the
10100 other template, so if any of the arguments are pack expansions, strip
10101 the alias to avoid problems with a pack expansion passed to a non-pack
10102 alias template parameter (DR 1430). */
10107 {
10108 tree parm;
10117 }
10118 else
10119 {
10121 tree gen_tmpl;
10122 tree type_decl;
10130 /* An error occurred while building the template TEMPL, and a
10131 diagnostic has most certainly been emitted for that
10132 already. Let's propagate that error. */
10144 {
10145 /* We've been given an incomplete set of template arguments.
10146 For example, given:
10148 template <class T> struct S1 {
10149 template <class U> struct S2 {};
10150 template <class U> struct S2<U*> {};
10151 };
10153 we will be called with an ARGLIST of `U*', but the
10154 TEMPLATE will be `template <class T> template
10155 <class U> struct S1<T>::S2'. We must fill in the missing
10156 arguments. */
10160 }
10162 /* Now we should have enough arguments. */
10166 {
10167 /* The user referred to a specialization of an alias
10168 template represented by GEN_TMPL.
10170 [temp.alias]/2 says:
10172 When a template-id refers to the specialization of an
10173 alias template, it is equivalent to the associated
10174 type obtained by substitution of its
10175 template-arguments for the template-parameters in the
10176 type-id of the alias template. */
10179 /* Note that the call above (by indirectly calling
10180 register_specialization in tsubst_decl) registers the
10181 TYPE_DECL representing the specialization of the alias
10182 template. So next time someone substitutes ARGLIST for
10183 the template parms into the alias template (GEN_TMPL),
10184 she'll get that TYPE_DECL back. */
10189 }
10191 /* From here on, we're only interested in the most general
10192 template. */
10194 /* Shortcut looking up the current class scope again. */
10198 {
10209 }
10211 /* Calculate the BOUND_ARGS. These will be the args that are
10212 actually tsubst'd into the definition to create the
10213 instantiation. */
10218 /* We were unable to bind the arguments. */
10221 /* In the scope of a template class, explicit references to the
10222 template class refer to the type of the template, not any
10223 instantiation of it. For example, in:
10225 template <class T> class C { void f(C<T>); }
10227 the `C<T>' is just the same as `C'. Outside of the
10228 class, however, such a reference is an instantiation.
10229 One can use adjust_type_for_entering_scope to make
10230 this adjustment as needed. */
10233 {
10238 }
10240 /* If we already have this specialization, return it. */
10241 spec_entry elt;
10249 /* If the template's constraints are not satisfied,
10250 then we cannot form a valid type.
10252 Note that the check is deferred until after the hash
10253 lookup. This prevents redundant checks on previously
10254 instantiated specializations. */
10257 {
10259 {
10260 auto_diagnostic_group d;
10263 }
10265 }
10269 /* If the deduced arguments are invalid, then the binding
10270 failed. */
10274 complain))
10281 /* This occurs when the user has tried to define a tagged type
10282 in a scope that forbids it. We emitted an error during the
10283 parse. We didn't complete the bail out then, so here we
10284 are. */
10289 {
10291 /* If the context of the partially instantiated template is
10292 already non-dependent, then we might as well use it. */
10294 else
10295 {
10298 /* Try completing the enclosing context if it's not already so. */
10301 {
10304 {
10305 /* Completion could have caused us to register the desired
10306 specialization already, so check the table again. */
10310 }
10311 }
10312 }
10313 }
10314 else
10323 /* Create the type. */
10325 {
10327 {
10338 }
10339 else
10340 {
10341 /* We don't want to call start_enum for this type, since
10342 the values for the enumeration constants may involve
10343 template parameters. And, no one should be interested
10344 in the enumeration constants for such a type. */
10347 }
10351 }
10353 {
10354 /* Lambda closures are regenerated in tsubst_lambda_expr, not
10355 instantiated here. */
10363 /* A local class. Make sure the decl gets registered properly. */
10370 /* This instantiation is another name for the primary
10371 template type. Set the TYPE_CANONICAL field
10372 appropriately. */
10376 }
10377 else
10380 /* If we called start_enum or pushtag above, this information
10381 will already be set up. */
10384 {
10391 }
10394 /* Although GEN_TMPL is the TEMPLATE_DECL, it has the same value
10395 of export flag. We want to propagate this because it might
10396 be a friend declaration that pushes a new hidden binding. */
10400 {
10406 {
10409 }
10410 }
10413 {
10417 {
10418 tree attributes
10426 }
10427 }
10429 /* Let's consider the explicit specialization of a member
10430 of a class template specialization that is implicitly instantiated,
10431 e.g.:
10432 template<class T>
10433 struct S
10434 {
10435 template<class U> struct M {}; //#0
10436 };
10438 template<>
10439 template<>
10440 struct S<int>::M<char> //#1
10441 {
10442 int i;
10443 };
10444 [temp.expl.spec]/4 says this is valid.
10446 In this case, when we write:
10447 S<int>::M<char> m;
10449 M is instantiated from the CLASSTYPE_TI_TEMPLATE of #1, not from
10450 the one of #0.
10452 When we encounter #1, we want to store the partial instantiation
10453 of M (template<class T> S<int>::M<T>) in its CLASSTYPE_TI_TEMPLATE.
10455 For all cases other than this "explicit specialization of member of a
10456 class template", we just want to store the most general template into
10457 the CLASSTYPE_TI_TEMPLATE of M.
10459 This case of "explicit specialization of member of a class template"
10460 only happens when:
10461 1/ the enclosing class is an instantiation of, and therefore not
10462 the same as, the context of the most general template, and
10463 2/ we aren't looking at the partial instantiation itself, i.e.
10464 the innermost arguments are not the same as the innermost parms of
10465 the most general template.
10467 So it's only when 1/ and 2/ happens that we want to use the partial
10468 instantiation of the member template in lieu of its most general
10469 template. */
10473 /* the enclosing class must be an instantiation... */
10476 {
10480 tree partial_inst_args =
10487 use_partial_inst_tmpl =
10488 /*...and we must not be looking at the partial instantiation
10489 itself. */
10491 partial_inst_args);
10492 }
10495 /* This case is easy; there are no member templates involved. */
10497 else
10498 {
10499 /* This is a full instantiation of a member template. Find
10500 the partial instantiation of which this is an instance. */
10502 /* Temporarily reduce by one the number of levels in the ARGLIST
10503 so as to avoid comparing the last set of arguments. */
10505 /* We don't use COMPLAIN in the following call because this isn't
10506 the immediate context of deduction. For instance, tf_partial
10507 could be set here as we might be at the beginning of template
10508 argument deduction when any explicitly specified template
10509 arguments are substituted into the function type. tf_partial
10510 could lead into trouble because we wouldn't find the partial
10511 instantiation that might have been created outside tf_partial
10512 context, because the levels of template parameters wouldn't
10513 match, because in a tf_partial context, tsubst doesn't reduce
10514 TEMPLATE_PARM_LEVEL. */
10518 ? found
10523 {
10524 /* If this partial instantiation is specialized, we want to
10525 use it for hash table lookup. */
10529 }
10530 }
10532 /* Build template info for the new specialization. */
10542 /* Note this use of the partial instantiation so we can check it
10543 later in maybe_process_partial_specialization. */
10550 /* Now that the type has been registered on the instantiations
10551 list, we set up the enumerators. Because the enumeration
10552 constants may involve the enumeration type itself, we make
10553 sure to register the type first, and then create the
10554 constants. That way, doing tsubst_expr for the enumeration
10555 constants won't result in recursive calls here; we'll find
10556 the instantiation and exit above. */
10560 /* If the type makes use of template parameters, the
10561 code that generates debugging information will crash. */
10564 /* Possibly limit visibility based on template args. */
10571 }
10572 }
10574 /* Return a TEMPLATE_ID_EXPR for the given variable template and ARGLIST. */
10576 tree
10578 {
10586 /* The type of the expression is NULL_TREE since the template-id could refer
10587 to an explicit or partial specialization. */
10589 }
10591 /* Instantiate a variable declaration from a TEMPLATE_ID_EXPR if it's
10592 not dependent. */
10594 tree
10596 {
10600 /* If the template or arguments are dependent, then we
10601 can't resolve the TEMPLATE_ID_EXPR yet. */
10607 {
10609 {
10610 auto_diagnostic_group d;
10613 }
10615 }
10618 }
10620 /* Construct a TEMPLATE_ID_EXPR for the given variable template TEMPL having
10621 TARGS template args, and instantiate it if it's not dependent. */
10623 tree
10625 tsubst_flags_t complain)
10626 {
10633 }
10635 /* If the set of template parameters PARMS contains a template parameter
10636 at the given LEVEL and INDEX, then return this parameter. Otherwise
10637 return NULL_TREE. */
10639 static tree
10641 {
10650 }
10652 /* Return the TREE_LIST for the template parameter from PARMS that positionally
10653 corresponds to the template parameter PARM, or else return NULL_TREE. */
10655 static tree
10657 {
10661 }
10663 /* As above, but pull out the actual parameter. */
10665 static tree
10667 {
10673 /* As in template_parm_to_arg. */
10676 else
10681 }
10682 \f
10683 struct pair_fn_data
10684 {
10685 tree_fn_t fn;
10686 tree_fn_t any_fn;
10688 /* True when we should also visit template parameters that occur in
10689 non-deduced contexts. */
10692 };
10694 /* Called from for_each_template_parm via walk_tree. */
10696 static tree
10698 {
10705 #define WALK_SUBTREE(NODE) \
10706 do \
10707 { \
10708 result = for_each_template_parm (NODE, fn, data, pfd->visited, \
10709 pfd->include_nondeduced_p, \
10710 pfd->any_fn); \
10711 if (result) goto out; \
10712 } \
10713 while (0)
10723 {
10727 /* Fall through. */
10733 else
10743 /* Since we're not going to walk subtrees, we have to do this
10744 explicitly here. */
10746 /* Fall through. */
10749 /* Check the return type. */
10752 /* Check the parameter types. Since default arguments are not
10753 instantiated until they are needed, the TYPE_ARG_TYPES may
10754 contain expressions that involve template parameters. But,
10755 no-one should be looking at them yet. And, once they're
10756 instantiated, they don't contain template parameters, so
10757 there's no point in looking at them then, either. */
10758 {
10759 tree parm;
10764 /* Since we've already handled the TYPE_ARG_TYPES, we don't
10765 want walk_tree walking into them itself. */
10767 }
10770 {
10774 }
10790 {
10793 }
10816 /* Record template parameters such as `T' inside `TT<T>'. */
10818 /* Fall through. */
10830 /* A template template parameter is encountered. */
10834 /* Already substituted template template parameter */
10839 /* A template-id in a TYPENAME_TYPE might be a deduced context after
10840 partial instantiation. */
10847 /* If there's no type, then this thing must be some expression
10848 involving template parameters. */
10858 /* These are non-deduced contexts. */
10880 }
10882 #undef WALK_SUBTREE
10884 /* We didn't find any template parameters we liked. */
10885 out:
10887 }
10889 /* For each TEMPLATE_TYPE_PARM, TEMPLATE_TEMPLATE_PARM,
10890 BOUND_TEMPLATE_TEMPLATE_PARM or TEMPLATE_PARM_INDEX in T,
10891 call FN with the parameter and the DATA.
10892 If FN returns nonzero, the iteration is terminated, and
10893 for_each_template_parm returns 1. Otherwise, the iteration
10894 continues. If FN never returns a nonzero value, the value
10895 returned by for_each_template_parm is 0. If FN is NULL, it is
10896 considered to be the function which always returns 1.
10898 If INCLUDE_NONDEDUCED_P, then this routine will also visit template
10899 parameters that occur in non-deduced contexts. When false, only
10900 visits those template parameters that can be deduced. */
10902 static tree
10906 tree_fn_t any_fn)
10907 {
10909 tree result;
10911 /* Set up. */
10917 /* Walk the tree. (Conceptually, we would like to walk without
10918 duplicates, but for_each_template_parm_r recursively calls
10919 for_each_template_parm, so we would need to reorganize a fair
10920 bit to use walk_tree_without_duplicates, so we keep our own
10921 visited list.) */
10924 else
10927 for_each_template_parm_r,
10931 /* Clean up. */
10933 {
10936 }
10939 }
10941 struct find_template_parameter_info
10942 {
10946 {}
10952 tree ctx_parms;
10959 };
10961 /* Appends the declaration of T to the list in DATA. */
10963 static int
10965 {
10968 /* Template parameters declared within the expression are not part of
10969 the parameter mapping. For example, in this concept:
10971 template<typename T>
10972 concept C = requires { <expr> } -> same_as<int>;
10974 the return specifier same_as<int> declares a new decltype parameter
10975 that must not be part of the parameter mapping. The same is true
10976 for generic lambda parameters, lambda template parameters, etc. */
10984 /* We want the underlying TEMPLATE_TEMPLATE_PARM, not the
10985 BOUND_TEMPLATE_TEMPLATE_PARM itself. */
10988 /* This template parameter might be an argument to a cached dependent
10989 specalization that was formed earlier inside some other template, in
10990 which case the parameter is not among the ones that are in-scope.
10991 Look in CTX_PARMS to find the corresponding in-scope template
10992 parameter, and use it instead. */
10996 /* Arguments like const T yield parameters like const T. This means that
10997 a template-id like X<T, const T> would yield two distinct parameters:
10998 T and const T. Adjust types to their unqualified versions. */
11002 {
11003 /* Append T to PARM_LIST. */
11007 }
11009 /* Verify the parameter we found has a valid index. */
11011 {
11017 }
11020 }
11022 /* Ensure that we recursively examine certain terms that are not normally
11023 visited in for_each_template_parm_r. */
11025 static int
11027 {
11030 #define WALK_SUBTREE(NODE) \
11031 do \
11032 { \
11033 for_each_template_parm (NODE, keep_template_parm, data, \
11034 &ftpi->visited, true, \
11035 any_template_parm_r); \
11036 } \
11037 while (0)
11039 /* A mention of a member alias/typedef is a use of all of its template
11040 arguments, including those from the enclosing class, so we don't use
11041 alias_template_specialization_p here. */
11047 {
11049 /* Type constraints of a placeholder type may contain parameters. */
11056 /* Search through references to variable templates. */
11066 /* If T is a member template that shares template parameters with
11067 ctx_parms, we need to mark all those parameters for mapping.
11068 To that end, it should suffice to just walk the DECL_CONTEXT of
11069 the template (assuming the template is not overly general). */
11074 {
11075 /* Look in the parms and body. */
11079 }
11084 /* The conversion-type-id of a conversion operator may be dependent. */
11095 }
11097 /* Keep walking. */
11099 }
11101 /* Look through T for template parameters. */
11103 tree
11105 {
11108 any_template_parm_r);
11109 }
11111 /* As above, but also recursively look into the default arguments of template
11112 parameters we found. Used for alias CTAD. */
11114 tree
11116 {
11119 /* Since newly found parms are added to the end of the list, we
11120 can just walk it until we reach the end. */
11122 {
11127 }
11129 }
11131 /* True if PARM was found by a previous call to find_in. PARM can be a
11132 TREE_LIST, a DECL_TEMPLATE_PARM_P, or a TEMPLATE_PARM_P. */
11134 bool
11136 {
11142 else
11146 }
11148 /* Returns a list of unique template parameters found within T, where CTX_PARMS
11149 are the template parameters in scope. */
11151 tree
11153 {
11160 }
11162 /* Returns true if T depends on any template parameter. */
11164 bool
11166 {
11170 /* Namespaces can't depend on any template parameters. */
11186 else
11188 }
11190 /* Returns true if T depends on any template parameter with level LEVEL. */
11192 bool
11194 {
11197 }
11199 /* Returns true if the signature of DECL depends on any template parameter from
11200 its enclosing class. */
11202 static bool
11204 {
11208 else
11217 {
11220 {
11225 template_parm_outer_level,
11235 }
11236 }
11240 }
11242 /* Returns true if the constraints of DECL depend on any template parameters
11243 from its enclosing scope. */
11245 bool
11247 {
11254 {
11257 else
11259 }
11265 }
11267 /* Returns TRUE iff INST is an instantiation we don't need to do in an
11268 ill-formed translation unit, i.e. a variable or function that isn't
11269 usable in a constant expression. */
11273 {
11279 }
11281 /* Returns TRUE iff we should refuse to instantiate DECL because it's
11282 neglectable and instantiated from within an erroneous instantiation. */
11284 static bool
11286 {
11292 /* Avoid instantiating members of an ill-formed class. */
11293 bool refuse
11298 {
11303 }
11306 {
11307 /* Don't warn about it not being defined. */
11309 tree clone;
11312 }
11314 }
11322 /* We're starting to instantiate D; record the template instantiation context
11323 at LOC for diagnostics and to restore it later. */
11325 bool
11327 {
11331 {
11332 /* Tell error.cc not to try to instantiate any templates. */
11335 "template instantiation depth exceeds maximum of %d"
11337 max_tinst_depth);
11339 }
11341 /* If the current instantiation caused problems, don't let it instantiate
11342 anything else. Do allow deduction substitution and decls usable in
11343 constant expressions. */
11345 {
11346 /* Avoid no_linkage_errors and unused function (and all other)
11347 warnings for this decl. */
11350 }
11352 /* When not -quiet, dump template instantiations other than functions, since
11353 announce_function will take care of those. */
11375 }
11377 /* We're starting substitution of TMPL<ARGS>; record the template
11378 substitution context for diagnostics and to restore it later. */
11380 bool
11382 {
11384 }
11386 /* We're starting to instantiate D; record INPUT_LOCATION and the
11387 template instantiation context for diagnostics and to restore it
11388 later. */
11390 bool
11392 {
11394 }
11396 /* Likewise, but record LOC as the program location. */
11398 bool
11400 {
11403 }
11405 /* We're done instantiating this template; return to the instantiation
11406 context. */
11408 void
11410 {
11411 /* Restore the filename and line number stashed away when we started
11412 this instantiation. */
11416 }
11418 /* We're instantiating a deferred template; restore the template
11419 instantiation context in which the instantiation was requested, which
11420 is one step out from LEVEL. Return the corresponding DECL or TYPE. */
11422 static tree
11424 {
11436 }
11438 /* Returns the TINST_LEVEL which gives the original instantiation
11439 context. */
11443 {
11449 }
11451 /* True iff T is a friend function declaration that is not itself a template
11452 and is not defined in a class template. */
11454 bool
11456 {
11459 {
11463 /* DECL_FRIEND_CONTEXT is set for a friend defined in class. */
11466 /* Non-templated friends in a class template are still represented with a
11467 TEMPLATE_DECL; check that its primary template is the befriending
11468 class. Note that DECL_PRIMARY_TEMPLATE is null for
11469 template <class T> friend A<T>::f(); */
11473 }
11474 else
11476 }
11478 /* DECL is a friend FUNCTION_DECL or TEMPLATE_DECL. ARGS is the
11479 vector of template arguments, as for tsubst.
11481 Returns an appropriate tsubst'd friend declaration. */
11483 static tree
11485 {
11486 tree new_friend;
11491 /* This was a friend declared with an explicit template
11492 argument list, e.g.:
11494 friend void f<>(T);
11496 to indicate that f was a template instantiation, not a new
11497 function declaration. Now, we have to figure out what
11498 instantiation of what template. */
11499 {
11501 tree new_args;
11502 tree tmpl;
11505 /* Friend functions are looked up in the containing namespace scope.
11506 We must enter that scope, to avoid finding member functions of the
11507 current class with same name. */
11521 tsk_none);
11523 }
11529 /* The NEW_FRIEND will look like an instantiation, to the
11530 compiler, but is not an instantiation from the point of view of
11531 the language. For example, we might have had:
11533 template <class T> struct S {
11534 template <class U> friend void f(T, U);
11535 };
11537 Then, in S<int>, template <class U> void f(int, U) is not an
11538 instantiation of anything. */
11542 {
11548 /* Substitute TEMPLATE_PARMS_CONSTRAINTS so that parameter levels will
11549 match in decls_match. */
11554 {
11556 /* As well as each TEMPLATE_PARM_CONSTRAINTS. */
11558 tf_warning_or_error);
11559 }
11560 }
11562 /* The mangled name for the NEW_FRIEND is incorrect. The function
11563 is not a template instantiation and should not be mangled like
11564 one. Therefore, we forget the mangling here; we'll recompute it
11565 later if we need it. */
11567 {
11570 }
11573 {
11574 tree old_decl;
11575 tree ns;
11577 /* We must save some information from NEW_FRIEND before calling
11578 duplicate decls since that function will free NEW_FRIEND if
11579 possible. */
11583 (new_friend_template_info
11590 {
11591 /* This declaration is a `primary' template. */
11596 }
11598 /* We need to propagate module attachment for the new friend from the
11599 owner of this template. */
11602 /* Inside pushdecl_namespace_level, we will push into the
11603 current namespace. However, the friend function should go
11604 into the namespace of the template. */
11614 {
11615 /* This new friend declaration matched an existing
11616 declaration. For example, given:
11618 template <class T> void f(T);
11619 template <class U> class C {
11620 template <class T> friend void f(T) {}
11621 };
11623 the friend declaration actually provides the definition
11624 of `f', once C has been instantiated for some type. So,
11625 old_decl will be the out-of-class template declaration,
11626 while new_friend is the in-class definition.
11628 But, if `f' was called before this point, the
11629 instantiation of `f' will have DECL_TI_ARGS corresponding
11630 to `T' but not to `U', references to which might appear
11631 in the definition of `f'. Previously, the most general
11632 template for an instantiation of `f' was the out-of-class
11633 version; now it is the in-class version. Therefore, we
11634 run through all specialization of `f', adding to their
11635 DECL_TI_ARGS appropriately. In particular, they need a
11636 new set of outer arguments, corresponding to the
11637 arguments for this class instantiation.
11639 The same situation can arise with something like this:
11641 friend void f(int);
11642 template <class T> class C {
11643 friend void f(T) {}
11644 };
11646 when `C<int>' is instantiated. Now, `f(int)' is defined
11647 in the class. */
11650 /* On the other hand, if the in-class declaration does
11651 *not* provide a definition, then we don't want to alter
11652 existing definitions. We can just leave everything
11653 alone. */
11654 ;
11655 else
11656 {
11661 /* Overwrite whatever template info was there before, if
11662 any, with the new template information pertaining to
11663 the declaration. */
11667 {
11668 /* We should have called reregister_specialization in
11669 duplicate_decls. */
11674 /* Instantiate it if the global has already been used. */
11678 }
11679 else
11680 {
11681 tree t;
11683 /* Indicate that the old function template is a partial
11684 instantiation. */
11692 /* Reassign any specializations already in the hash table
11693 to the new more general template, and add the
11694 additional template args. */
11698 {
11700 spec_entry elt;
11709 spec_args = add_outermost_template_args
11712 register_specialization
11715 }
11717 }
11718 }
11720 /* The information from NEW_FRIEND has been merged into OLD_DECL
11721 by duplicate_decls. */
11723 }
11725 /* We've just introduced a namespace-scope function in the purview
11726 without necessarily having opened the enclosing namespace, so
11727 make sure the namespace is in the purview now too. */
11732 }
11733 else
11734 {
11738 /* In the code
11739 template <class T> class C {
11740 template <class U> friend void C1<U>::f (); // case 1
11741 friend void C2<T>::f (); // case 2
11742 };
11743 we only need to make sure CONTEXT is a complete type for
11744 case 2. To distinguish between the two cases, we note that
11745 CONTEXT of case 1 remains dependent type after tsubst while
11746 this isn't true for case 2. */
11756 {
11758 /* do_friend adds the TEMPLATE_DECL for any member friend
11759 template even if it isn't a member template, i.e.
11760 template <class T> friend A<T>::f();
11761 Look through it in that case. */
11765 /* Check to see that the declaration is really present, and,
11766 possibly obtain an improved declaration. */
11771 }
11772 }
11775 }
11777 /* FRIEND_TMPL is a friend TEMPLATE_DECL. ARGS is the vector of
11778 template arguments, as for tsubst.
11780 Returns an appropriate tsubst'd friend type or error_mark_node on
11781 failure. */
11783 static tree
11785 {
11786 tree tmpl;
11789 {
11792 }
11795 /* The template has already been fully substituted, e.g. for
11797 template <typename> friend class ::C;
11799 so we can just return it directly. */
11805 else
11806 {
11809 }
11815 /* If we didn't find by name lookup, the type may still exist but as a
11816 'hidden' import; we should check for this too to avoid accidentally
11817 instantiating a duplicate. */
11821 {
11822 /* The friend template has already been declared. Just
11823 check to see that the declarations match, and install any new
11824 default parameters. We must tsubst the default parameters,
11825 of course. We only need the innermost template parameters
11826 because that is all that redeclare_class_template will look
11827 at. */
11830 /* Check that the existing declaration's module attachment is
11831 compatible with the attachment of the friend template. */
11835 {
11839 tf_warning_or_error);
11849 }
11850 }
11851 else
11852 {
11853 /* The friend template has not already been declared. In this
11854 case, the instantiation of the template class will cause the
11855 injection of this template into the namespace scope. */
11859 {
11860 /* The new TMPL is not an instantiation of anything, so we
11861 forget its origins. It is also not a specialization of
11862 anything. We don't reset CLASSTYPE_TI_TEMPLATE
11863 for the new type because that is supposed to be the
11864 corresponding template decl, i.e., TMPL. */
11865 spec_entry elt;
11878 /* Substitute into and set the constraints on the new declaration. */
11880 {
11888 }
11890 /* We need to propagate the attachment of the original template to the
11891 newly instantiated template type. */
11894 /* Inject this template into the enclosing namspace scope. */
11896 }
11897 }
11901 else
11905 }
11907 /* Returns zero if TYPE cannot be completed later due to circularity.
11908 Otherwise returns one. */
11910 static int
11912 {
11922 else
11924 }
11929 /* Instantiate the contract statement. */
11931 static tree
11933 tree in_decl)
11934 {
11940 /* Rebuild the result variable. */
11942 {
11950 /* Make sure the postcondition is valid. */
11956 /* Make the variable available for lookup. */
11958 }
11960 /* Instantiate the condition. If the return type is undeduced, process
11961 the expression as if inside a template to avoid spurious type errors. */
11971 /* And the comment. */
11976 }
11978 /* Update T by instantiating its contract attribute. */
11980 static void
11983 {
11984 /* For non-specializations, adjust the current declaration to the most general
11985 version of in_decl. Because we defer the instantiation of contracts as long
11986 as possible, they are still written in terms of the parameters (and return
11987 type) of the most general template. */
11994 /* Get the contract to be instantiated. */
11997 /* Use the complete set of template arguments for instantiation. The
11998 contract may not have been instantiated and still refer to outer levels
11999 of template parameters. */
12002 /* For member functions, make this available for semantic analysis. */
12006 {
12010 }
12017 /* Rebuild the attribute. */
12019 }
12021 /* Rebuild the attribute list for DECL, substituting into contracts
12022 as needed. */
12024 void
12026 {
12029 {
12032 }
12034 }
12036 /* Instantiate a single dependent attribute T (a TREE_LIST), and return either
12037 T or a new TREE_LIST, possibly a chain in the case of a pack expansion. */
12039 static tree
12042 {
12045 /* Note that contract attributes are never substituted from this function.
12046 Their instantiation is triggered by regenerate_from_template_decl when
12047 we instantiate the body of the function. */
12055 {
12062 clauses
12066 else
12068 }
12072 {
12080 {
12085 {
12088 /* FIXME: The body of this loop should really be dispatching
12089 according to omp_ts_map[OMP_TS_CODE (TS)].tp_type instead
12090 of having hard-wired knowledge of specific selectors. */
12093 {
12101 }
12102 else
12103 {
12106 {
12111 {
12112 location_t loc
12114 match_loc);
12118 }
12120 {
12121 location_t loc
12123 match_loc);
12127 }
12129 }
12135 {
12136 bool allow_string
12146 {
12147 location_t loc
12149 match_loc);
12152 "integer expression or string "
12154 else
12158 }
12160 }
12161 }
12164 }
12166 }
12168 }
12169 /* If the first attribute argument is an identifier, don't
12170 pass it through tsubst. Attributes like mode, format,
12171 cleanup and several target specific attributes expect it
12172 unmodified. */
12174 {
12175 tree chain
12179 }
12181 {
12182 /* An attribute pack expansion. */
12191 {
12195 }
12197 }
12198 else
12206 }
12208 /* Instantiate any dependent attributes in ATTRIBUTES, returning either it
12209 unchanged or a new TREE_LIST chain. */
12211 static tree
12214 {
12219 {
12223 }
12227 {
12230 {
12233 {
12239 }
12240 }
12242 }
12245 }
12247 /* Apply any attributes which had to be deferred until instantiation
12248 time. DECL_P, ATTRIBUTES and ATTR_FLAGS are as cplus_decl_attributes;
12249 ARGS, COMPLAIN, IN_DECL are as tsubst. Returns true normally,
12250 false on error. */
12252 static bool
12255 {
12256 tree t;
12263 {
12267 /* DECL_ATTRIBUTES comes from copy_node in tsubst_decl, and is identical
12268 to our attributes parameter. */
12270 }
12273 else
12274 {
12276 /* TYPE_ATTRIBUTES was set up (with abi_tag and may_alias) in
12277 lookup_template_class_1, and should be preserved. */
12281 }
12283 /* save_template_attributes puts the dependent attributes at the beginning of
12284 the list; find the non-dependent ones. */
12290 /* Apply any non-dependent attributes. */
12299 /* And then any dependent ones. */
12303 {
12308 {
12311 }
12314 }
12316 /* cplus_decl_attributes can add some attributes implicitly. For templates,
12317 those attributes should have been added already when those templates were
12318 parsed, and shouldn't be added based on from which context they are
12319 first time instantiated. */
12322 optimization_default_node);
12325 NULL);
12331 }
12333 /* The template TMPL is being instantiated with the template arguments TARGS.
12334 Perform the access checks that we deferred when parsing the template. */
12336 static void
12338 {
12348 {
12356 /* Make access check error messages point to the location
12357 of the use of the typedef. */
12361 }
12362 }
12364 /* If the template T that we're about to instantiate contained errors at
12365 parse time that we downgraded into warnings or suppressed, diagnose the
12366 error now to render the TU ill-formed (if the TU has not already been
12367 deemed ill-formed by an earlier error). */
12369 static void
12371 {
12374 {
12375 auto_diagnostic_group d;
12379 }
12380 }
12382 tree
12384 {
12388 tree typedecl;
12389 tree pbinfo;
12390 tree base_list;
12392 tree fn_context;
12401 /* Figure out which template is being instantiated. */
12405 /* Mark the type as in the process of being defined. */
12408 /* We may be in the middle of deferred access check. Disable
12409 it now. */
12412 /* Determine what specialization of the original template to
12413 instantiate. */
12418 {
12419 /* This TYPE is actually an instantiation of a partial
12420 specialization. We replace the innermost set of ARGS with
12421 the arguments appropriate for substitution. For example,
12422 given:
12424 template <class T> struct S {};
12425 template <class T> struct S<T*> {};
12427 and supposing that we are instantiating S<int*>, ARGS will
12428 presently be {int*} -- but we need {int}. */
12431 }
12432 else
12433 {
12436 }
12438 /* If the template we're instantiating is incomplete, then clearly
12439 there's nothing we can do. */
12441 {
12442 /* We can try again later. */
12445 }
12447 /* If we've recursively instantiated too many templates, stop. */
12457 /* Also avoid push_to_top_level for a lambda in an NSDMI. */
12462 else
12463 {
12466 }
12470 /* Use #pragma pack from the template context. */
12476 /* Set the input location to the most specialized template definition.
12477 This is needed if tsubsting causes an error. */
12491 {
12494 /* Adjust visibility for template arguments. */
12496 }
12502 /* We should never instantiate a nested class before its enclosing
12503 class; we need to look up the nested class by name before we can
12504 instantiate it, and that lookup should instantiate the enclosing
12505 class. */
12510 /* Defer access checking while we substitute into the types named in
12511 the base-clause. */
12514 {
12515 tree pbase_binfo;
12518 /* Substitute into each of the bases to determine the actual
12519 basetypes. */
12521 {
12522 tree base;
12528 {
12529 expanded_bases =
12536 }
12539 {
12541 /* Extract the already-expanded base class. */
12543 else
12544 /* Substitute to figure out the base class. */
12546 NULL_TREE);
12554 }
12555 }
12557 /* The list is now in reverse order; correct that. */
12559 }
12560 /* Now call xref_basetypes to set up all the base-class
12561 information. */
12569 /* Now that our base classes are set up, enter the scope of the
12570 class, so that name lookups into base classes, etc. will work
12571 correctly. This is precisely analogous to what we do in
12572 begin_class_definition when defining an ordinary non-template
12573 class, except we also need to push the enclosing classes. */
12576 /* Now check accessibility of the types named in its base-clause,
12577 relative to the scope of the class. */
12580 /* A vector to hold members marked with attribute used. */
12583 /* Now members are processed in the order of declaration. */
12586 {
12590 {
12592 {
12594 /* A closure type for a lambda in an NSDMI or default argument.
12595 Ignore it; it will be regenerated when needed. */
12598 /* If the member is a class template, we've
12599 already substituted its type. */
12609 {
12612 /* Now, install the tag. We don't use pushtag
12613 because that does too much work -- creating an
12614 implicit typedef, which we've already done. */
12619 }
12620 }
12622 {
12623 tree r;
12633 /* Instantiate members marked with attribute used. */
12639 }
12642 /* A closure type for a lambda in an NSDMI or default argument.
12644 else
12645 {
12646 /* Build new TYPE_FIELDS. */
12650 {
12651 tree r;
12656 /* The file and line for this declaration, to
12657 assist in error message reporting. Since we
12658 called push_tinst_level above, we don't need to
12659 restore these. */
12669 {
12670 /* A capture pack became multiple fields. */
12673 }
12676 {
12680 {
12681 /* In [temp.inst]:
12683 [t]he initialization (and any associated
12684 side-effects) of a static data member does
12685 not occur unless the static data member is
12686 itself used in a way that requires the
12687 definition of the static data member to
12688 exist.
12690 Therefore, we do not substitute into the
12691 initialized for the static data member here. */
12692 finish_static_data_member_decl
12698 /* Instantiate members marked with attribute used. */
12701 }
12703 {
12704 /* Determine whether R has a valid type and can be
12705 completed later. If R is invalid, then its type
12706 is replaced by error_mark_node. */
12712 {
12713 /* If R's type couldn't be completed and
12714 it isn't a flexible array member (whose
12715 type is incomplete by definition) give
12716 an error. */
12719 }
12724 {
12727 }
12731 }
12733 /* If it is a TYPE_DECL for a class-scoped
12734 ENUMERAL_TYPE, such a thing will already have
12735 been added to the field list by tsubst_enum
12736 in finish_member_declaration case above. */
12740 {
12743 }
12744 }
12745 }
12746 }
12747 }
12748 else
12749 {
12752 {
12753 /* Build new CLASSTYPE_FRIEND_CLASSES. */
12757 {
12758 /* template <class T> friend class C; */
12760 }
12762 {
12763 /* template <class T> friend class C::D; */
12768 }
12771 {
12772 /* This could be either
12774 friend class T::C;
12776 when dependent_type_p is false or
12778 template <class U> friend class T::C;
12780 otherwise. */
12781 /* Bump processing_template_decl in case this is something like
12782 template <class T> friend struct A<T>::B. */
12787 }
12789 {
12791 tf_warning_or_error,
12792 NULL_TREE);
12794 {
12801 }
12803 }
12805 /* friend class C<T>; */
12809 /* Otherwise it's
12811 friend class C;
12813 where C is already declared or
12815 friend class C<int>;
12817 We don't have to do anything in these cases. */
12821 }
12822 else
12823 {
12824 /* Build new DECL_FRIENDLIST. */
12825 tree r;
12827 /* The file and line for this declaration, to
12828 assist in error message reporting. Since we
12829 called push_tinst_level above, we don't need to
12830 restore these. */
12834 {
12837 }
12842 {
12845 }
12846 }
12847 }
12848 }
12851 {
12852 /* Restore these before substituting into the lambda capture
12853 initializers. */
12856 }
12858 /* Set the file and line number information to whatever is given for
12859 the class itself. This puts error messages involving generated
12860 implicit functions at a predictable point, and the same point
12861 that would be used for non-template classes. */
12868 /* Remember if instantiating this class ran into errors, so we can avoid
12869 instantiating member functions in limit_bad_template_recursion. We set
12870 this flag even if the problem was in another instantiation triggered by
12871 this one, as that will likely also cause trouble for member functions. */
12875 /* We don't instantiate default arguments for member functions. 14.7.1:
12877 The implicit instantiation of a class template specialization causes
12878 the implicit instantiation of the declarations, but not of the
12879 definitions or default arguments, of the class member functions,
12880 member classes, static data members and member templates.... */
12885 /* Now that we've gone through all the members, instantiate those
12886 marked with attribute used. We must do this in the context of
12887 the class -- not the context we pushed from, as that might be
12888 inside a template and change the behaviour of mark_used. */
12898 /* The vtable for a template class can be emitted in any translation
12899 unit in which the class is instantiated. When there is no key
12900 method, however, finish_struct_1 will already have added TYPE to
12901 the keyed_classes. */
12906 }
12908 tree
12910 {
12911 tree r;
12917 else
12918 {
12924 }
12927 }
12929 /* Given a function parameter pack TMPL_PARM and some function parameters
12930 instantiated from it at *SPEC_P, return a NONTYPE_ARGUMENT_PACK of them
12931 and set *SPEC_P to point at the next point in the list. */
12933 tree
12935 {
12936 /* Collect all of the extra "packed" parameters into an
12937 argument pack. */
12938 tree argpack;
12949 {
12950 /* The instantiation is still a parameter pack; don't wrap it in a
12951 NONTYPE_ARGUMENT_PACK. */
12954 }
12955 else
12956 {
12957 /* Fill in PARMVEC with all of the parameters. */
12961 {
12967 }
12969 /* Build the argument packs. */
12971 }
12975 }
12977 /* Give a chain SPEC_PARM of PARM_DECLs, pack them into a
12978 NONTYPE_ARGUMENT_PACK. */
12980 static tree
12982 {
12984 }
12986 /* Return 1 if the Ith element of the argument pack ARG_PACK is a
12987 pack expansion with no extra args, 2 if it has extra args, or 0
12988 if it is not a pack expansion. */
12990 static int
12992 {
12994 /* We're being called before this happens in tsubst_pack_expansion. */
13001 /* A decl pack is itself an expansion. */
13008 }
13011 /* Creates and return an ARGUMENT_PACK_SELECT tree node. */
13013 static tree
13015 {
13022 }
13024 /* This is a subroutine of tsubst_pack_expansion.
13026 It returns TRUE if we need to use the PACK_EXPANSION_EXTRA_ARGS
13027 mechanism to store the (non complete list of) arguments of the
13028 substitution and return a non substituted pack expansion, in order
13029 to wait for when we have enough arguments to really perform the
13030 substitution. */
13032 static bool
13034 tree parm_packs,
13037 {
13042 /* If one pack has an expansion and another pack has a normal
13043 argument or if one pack has an empty argument and an another
13044 one hasn't then tsubst_pack_expansion cannot perform the
13045 substitution and need to fall back on the
13046 PACK_EXPANSION_EXTRA mechanism. */
13050 {
13051 /* If all the actual packs are pack expansions, we can still
13052 subsitute directly. */
13054 {
13064 }
13066 }
13069 {
13073 parm_pack;
13075 {
13080 /* We can't substitute a pack expansion with extra args into
13081 our pattern. */
13085 else
13087 }
13090 {
13093 }
13094 }
13096 }
13098 /* [temp.variadic]/6 says that:
13100 The instantiation of a pack expansion [...]
13101 produces a list E1,E2, ..., En, where N is the number of elements
13102 in the pack expansion parameters.
13104 This subroutine of tsubst_pack_expansion produces one of these Ei.
13106 PATTERN is the pattern of the pack expansion. PARM_PACKS is a
13107 TREE_LIST in which each TREE_PURPOSE is a parameter pack of
13108 PATTERN, and each TREE_VALUE is its corresponding argument pack.
13109 INDEX is the index 'i' of the element Ei to produce. ARGS,
13110 COMPLAIN, and IN_DECL are the same parameters as for the
13111 tsubst_pack_expansion function.
13113 The function returns the resulting Ei upon successful completion,
13114 or error_mark_node.
13116 Note that this function possibly modifies the ARGS parameter, so
13117 it's the responsibility of the caller to restore it. */
13119 static tree
13121 tree parm_packs,
13123 tree args /* This parm gets
13125 tsubst_flags_t complain,
13126 tree in_decl)
13127 {
13128 tree t;
13131 /* For each parameter pack, change the substitution of the parameter
13132 pack to the ith argument in its argument pack, then expand the
13133 pattern. */
13135 {
13140 ith_elem_is_expansion |=
13143 /* Select the Ith argument from the pack. */
13147 {
13149 {
13154 }
13155 else
13157 }
13158 else
13159 {
13164 {
13166 /* Update the corresponding argument. */
13168 }
13169 else
13170 /* Re-use the ARGUMENT_PACK_SELECT. */
13172 }
13174 }
13176 /* Substitute into the PATTERN with the (possibly altered)
13177 arguments. */
13179 /* Expanding a fixed parameter pack from
13180 coerce_template_parameter_pack. */
13186 else
13187 {
13190 /* When expanding the fake auto... pack expansion from add_capture, we
13191 need to mark that the expansion is no longer a pack. */
13193 }
13195 /* If the Ith argument pack element is a pack expansion, then
13196 the Ith element resulting from the substituting is going to
13197 be a pack expansion as well. */
13202 }
13204 /* When the unexpanded parameter pack in a fold expression expands to an empty
13205 sequence, the value of the expression is as follows; the program is
13206 ill-formed if the operator is not listed in this table.
13208 && true
13209 || false
13210 , void() */
13212 tree
13214 {
13218 {
13227 }
13233 }
13235 /* Given a fold-expression T and a current LEFT and RIGHT operand,
13236 form an expression that combines the two terms using the
13237 operator of T. */
13239 static tree
13241 {
13246 // Handle compound assignment operators.
13253 {
13262 complain);
13263 }
13264 }
13266 /* Substitute ARGS into the pack of a fold expression T. */
13270 {
13272 }
13274 /* Substitute ARGS into the pack of a fold expression T. */
13278 {
13280 }
13282 /* Expand a PACK of arguments into a grouped as left fold.
13283 Given a pack containing elements A0, A1, ..., An and an
13284 operator @, this builds the expression:
13286 ((A0 @ A1) @ A2) ... @ An
13288 Note that PACK must not be empty.
13290 The operator is defined by the original fold expression T. */
13292 static tree
13294 {
13297 {
13300 }
13302 }
13304 /* Substitute into a unary left fold expression. */
13306 static tree
13308 tree in_decl)
13309 {
13314 {
13318 }
13321 else
13323 }
13325 /* Substitute into a binary left fold expression.
13327 Do ths by building a single (non-empty) vector of argumnts and
13328 building the expression from those elements. */
13330 static tree
13332 tree in_decl)
13333 {
13342 {
13347 }
13355 }
13357 /* Expand a PACK of arguments into a grouped as right fold.
13358 Given a pack containing elementns A0, A1, ..., and an
13359 operator @, this builds the expression:
13361 A0@ ... (An-2 @ (An-1 @ An))
13363 Note that PACK must not be empty.
13365 The operator is defined by the original fold expression T. */
13367 tree
13369 {
13370 // Build the expression.
13374 {
13377 }
13379 }
13381 /* Substitute into a unary right fold expression. */
13383 static tree
13385 tree in_decl)
13386 {
13391 {
13395 }
13398 else
13400 }
13402 /* Substitute into a binary right fold expression.
13404 Do ths by building a single (non-empty) vector of arguments and
13405 building the expression from those elements. */
13407 static tree
13409 tree in_decl)
13410 {
13419 {
13424 }
13433 }
13435 /* Walk through the pattern of a pack expansion, adding everything in
13436 local_specializations to a list. */
13438 class el_data
13439 {
13441 /* Set of variables declared within the pattern. */
13443 /* Set of AST nodes that have been visited by the traversal. */
13445 /* List of local_specializations used within the pattern. */
13446 tree extra;
13447 tsubst_flags_t complain;
13448 /* True iff we don't want to walk into unevaluated contexts. */
13450 /* The unevaluated contexts that we avoided walking. */
13455 };
13456 static tree
13458 {
13465 {
13469 }
13472 /* Remember local typedefs (85214). */
13476 /* Assert *_EXTRA_ARGS is empty, because we don't want to walk it and
13477 potentially see a previously captured local in an evaluated context
13478 that's really only used in an unevaluated context (PR114303). This
13479 means callers of build_extra_args need to clear *_EXTRA_ARGS of the
13480 outermost tree. Nested *_EXTRA_ARGS should naturally be empty since
13481 the outermost (extra-args) tree will intercept any substitution before
13482 a nested tree can. */
13484 /* Except a lambda nested inside an extra-args tree
13485 can have extra args if we deferred partial
13486 substitution into it at template parse time. But
13487 we don't walk LAMBDA_EXPR_EXTRA_ARGS anyway. */
13491 {
13496 {
13499 decl2
13504 {
13507 }
13508 }
13509 }
13511 {
13512 /* Since we defer implicit capture, look in the parms and body. */
13518 }
13520 {
13522 /* Don't mess with variables declared within the pattern. */
13525 {
13526 /* Maybe pull out the PARM_DECL for a partial instantiation. */
13529 {
13535 }
13537 {
13538 /* Handle lambda capture here, since we aren't doing any
13539 substitution now, and so tsubst_copy won't call
13540 process_outer_var_ref. */
13544 {
13550 {
13551 /* Make a new NONTYPE_ARGUMENT_PACK of the capture
13552 proxies. */
13554 {
13559 }
13561 }
13562 }
13563 }
13564 }
13568 }
13570 }
13571 static tree
13573 {
13575 /* Walk the pattern twice, ignoring unevaluated operands the first time
13576 around, so that if a local specialization appears in both an evaluated
13577 and unevaluated context we prefer to process it in the evaluated context
13578 (since e.g. process_outer_var_ref is a no-op inside an unevaluated
13579 context). */
13582 /* Now walk the unevaluated contexts we skipped the first time around. */
13585 {
13588 }
13590 }
13592 /* Extract any uses of local_specializations from PATTERN and add them to ARGS
13593 for use in PACK_EXPANSION_EXTRA_ARGS. */
13595 tree
13597 {
13598 /* Make a copy of the extra arguments so that they won't get changed
13599 out from under us. */
13602 /* Remember whether this is a partial substitution. */
13608 }
13610 /* Apply any local specializations from PACK_EXPANSION_EXTRA_ARGS and add the
13611 normal template args to ARGS. */
13613 tree
13615 {
13620 {
13622 {
13623 /* The partial instantiation involved local declarations collected in
13624 extract_local_specs; map from the general template to our local
13625 context. */
13631 /* else inst is already a full instantiation of the pack. */
13633 }
13636 }
13639 /* This is a partial substitution into e.g. a requires-expr or lambda-expr
13640 inside a default template argument; we expect 'extra' to be a full set
13641 of template arguments for the template context, so it suffices to just
13642 substitute into them. */
13644 else
13647 }
13649 /* Substitute ARGS into T, which is an pack expansion
13650 (i.e. TYPE_PACK_EXPANSION or EXPR_PACK_EXPANSION). Returns a
13651 TREE_VEC with the substituted arguments, a PACK_EXPANSION_* node
13652 (if only a partial substitution could be performed) or
13653 ERROR_MARK_NODE if there was an error. */
13654 tree
13656 tree in_decl)
13657 {
13658 tree pattern;
13662 tree result;
13669 /* Add in any args remembered from an earlier partial instantiation. */
13674 /* Determine the argument packs that will instantiate the parameter
13675 packs used in the expansion expression. While we're at it,
13676 compute the number of arguments to be expanded and make sure it
13677 is consistent. */
13680 {
13687 {
13692 else
13694 }
13696 {
13698 {
13701 parm_pack);
13703 }
13706 }
13708 {
13709 /* We know we have correct local_specializations if this
13710 expansion is at function scope, or if we're dealing with a
13711 local parameter in a requires expression; for the latter,
13712 tsubst_requires_expr set it up appropriately. */
13715 else
13716 /* We can't rely on local_specializations for a parameter
13717 name used later in a function declaration (such as in a
13718 late-specified return type). Even if it exists, it might
13719 have the wrong value for a recursive call. */
13723 {
13724 /* This parameter pack was used in an unevaluated context. Just
13725 make a dummy decl, since it's only used for its type. */
13730 /* Partial instantiation of the parm_pack, we can't build
13731 up an argument pack yet. */
13733 else
13735 }
13737 /* This argument pack isn't fully instantiated yet. */
13739 }
13741 {
13745 }
13746 else
13747 {
13756 }
13763 /* This can only happen if we forget to expand an argument
13764 pack somewhere else. Just return an error, silently. */
13765 {
13769 }
13772 {
13776 /* Don't bother trying to do a partial substitution with
13777 incomplete packs; we'll try again after deduction. */
13784 {
13789 pattern);
13790 else
13792 pattern);
13794 }
13796 /* Keep track of the parameter packs and their corresponding
13797 argument packs. */
13800 }
13801 else
13802 {
13803 /* We can't substitute for this parameter pack. We use a flag as
13804 well as the missing_level counter because function parameter
13805 packs don't have a level. */
13808 }
13809 }
13811 /* If the expansion is just T..., return the matching argument pack, unless
13812 we need to call convert_from_reference on all the elements. This is an
13813 important optimization; see c++/68422. */
13816 {
13819 /* If the argument pack is a single pack expansion, pull it out. */
13822 {
13826 /* Except if this isn't a simple sizeof...(T) which gets sZ
13828 else
13830 }
13832 /* Types need no adjustment, nor does sizeof..., and if we still have
13833 some pack expansion args we won't do anything yet. */
13838 /* Also optimize expression pack expansions if we can tell that the
13839 elements won't have reference type. */
13845 /* Otherwise use the normal path so we get convert_from_reference. */
13846 }
13848 /* We cannot expand this expansion expression, because we don't have
13849 all of the argument packs we need. */
13851 {
13852 /* We got some full packs, but we can't substitute them in until we
13853 have values for all the packs. So remember these until then. */
13859 }
13861 /* If NEED_LOCAL_SPECIALIZATIONS then we're in a late-specified return
13862 type, so create our own local specializations map; the current map is
13863 either NULL or (in the case of recursive unification) might have
13864 bindings that we don't want to use or alter. */
13869 {
13870 /* There were no real arguments, we're just replacing a parameter
13871 pack with another version of itself. Substitute into the
13872 pattern and return a PACK_EXPANSION_*. The caller will need to
13873 deal with that. */
13876 else
13884 {
13885 /* This is a fake auto... pack expansion created in add_capture with
13886 _PACKS that don't appear in the pattern. Copy one over. */
13893 }
13895 }
13899 /* For each argument in each argument pack, substitute into the
13900 pattern. */
13904 {
13906 i,
13908 in_decl);
13911 {
13914 }
13915 }
13917 /* Update ARGS to restore the substitution from parameter packs to
13918 their argument packs. */
13920 {
13927 else
13928 {
13936 /* Update the corresponding argument. */
13940 else
13942 }
13943 }
13945 /* If the dependent pack arguments were such that we end up with only a
13946 single pack expansion again, there's no need to keep it in a TREE_VEC. */
13952 }
13954 /* Make an argument pack out of the TREE_VEC VEC. */
13956 static tree
13958 {
13959 tree pack;
13963 else
13964 {
13967 }
13970 }
13972 /* Return an exact copy of template args T that can be modified
13973 independently. */
13975 static tree
13977 {
13985 {
13990 }
13996 }
13998 /* Substitute ARGS into the *_ARGUMENT_PACK orig_arg. */
14000 tree
14002 tree in_decl)
14003 {
14004 /* This flag is used only during deduction, and we don't expect to
14005 substitute such ARGUMENT_PACKs. */
14008 /* Substitute into each of the arguments. */
14017 /* If we're substituting into a generic ARGUMENT_PACK for a variadic
14018 template parameter, we might be able to avoid allocating a new
14019 ARGUMENT_PACK and reuse the corresponding ARGUMENT_PACK from ARGS
14020 if the substituted result is identical to it. */
14022 {
14029 {
14032 }
14033 }
14035 tree new_arg;
14037 {
14040 }
14041 else
14042 {
14045 }
14048 }
14050 /* Substitute ARGS into the vector or list of template arguments T. */
14052 tree
14054 {
14058 /* In "sizeof(X<I>)" we need to evaluate "I". */
14059 cp_evaluated ev;
14065 /* True iff the substituted result is identical to T. */
14069 {
14071 tree new_arg;
14078 {
14079 /* Substitute into an expansion expression. */
14083 /* Add to the expanded length adjustment the number of
14084 expanded arguments. We subtract one from this
14085 measurement, because the argument pack expression
14086 itself is already counted as 1 in
14087 LEN. EXPANDED_LEN_ADJUST can actually be negative, if
14088 the argument pack is empty. */
14090 }
14093 else
14102 }
14109 /* If ARGS and T are both multi-level, the substituted result may be
14110 identical to ARGS. */
14115 /* If T appears to be a vector of generic template arguments, the
14116 substituted result may be identical to the corresponding level
14117 from ARGS. */
14119 {
14124 }
14126 /* If the substituted result is identical to MAYBE_REUSE, return
14127 it and avoid allocating a new TREE_VEC, as an optimization. */
14133 /* If T consists of only a pack expansion for which substitution yielded
14134 a TREE_VEC of the expanded elements, then reuse that TREE_VEC instead
14135 of effectively making a copy. */
14141 /* Make space for the expanded arguments coming from template
14142 argument packs. */
14144 /* T can contain TREE_VECs. That happens if T contains the
14145 arguments for a member template.
14146 In that case each TREE_VEC in T represents a level of template
14147 arguments, and T won't carry any non defaulted argument count.
14148 It will rather be the nested TREE_VECs that will carry one.
14149 In other words, T carries a non defaulted argument count only
14150 if it doesn't contain any nested TREE_VEC. */
14152 {
14156 }
14160 {
14165 {
14166 /* Now expand the template argument pack "in place". */
14169 }
14170 else
14171 {
14173 out++;
14174 }
14175 }
14179 }
14181 /* Substitute ARGS into one level PARMS of template parameters. */
14183 static tree
14185 {
14192 {
14200 }
14203 }
14205 /* Return the result of substituting ARGS into the template parameters
14206 given by PARMS. If there are m levels of ARGS and m + n levels of
14207 PARMS, then the result will contain n levels of PARMS. For
14208 example, if PARMS is `template <class T> template <class U>
14209 template <T*, U, class V>' and ARGS is {{int}, {double}} then the
14210 result will be `template <int*, double, class V>'. */
14212 static tree
14214 {
14218 /* When substituting into a template, we must set
14219 PROCESSING_TEMPLATE_DECL as the template parameters may be
14220 dependent if they are based on one-another, and the dependency
14221 predicates are short-circuit outside of templates. */
14228 {
14237 }
14242 }
14244 /* Return the result of substituting ARGS into one template parameter
14245 given by T. T Must be a TREE_LIST which TREE_VALUE is the template
14246 parameter and which TREE_PURPOSE is the default argument of the
14247 template parameter. */
14249 static tree
14251 {
14274 }
14276 /* Substitute in-place the TEMPLATE_PARM_CONSTRAINTS of each template
14277 parameter in PARMS for sake of declaration matching. */
14279 static void
14281 tsubst_flags_t complain)
14282 {
14285 {
14291 }
14293 }
14295 /* Map from a FUNCTION_DECL to a vec of default argument instantiations,
14296 indexed in reverse order of the parameters. */
14300 /* Return a reference to the vec* of defarg insts for FN. */
14304 {
14308 tree_vec_map **slot
14311 {
14314 }
14316 }
14318 /* Substitute into the default argument ARG (a default argument for
14319 FN), which has the indicated TYPE. */
14321 tree
14323 tsubst_flags_t complain)
14324 {
14327 /* This can happen in invalid code. */
14331 /* Shortcut {}. */
14346 /* Remember the location of the pointer to the vec rather than the location
14347 of the particular element, in case the vec grows in tsubst_expr. */
14349 /* Index in reverse order to avoid allocating space for initial parameters
14350 that don't have default arguments. */
14357 /* This default argument came from a template. Instantiate the
14358 default argument here, not in tsubst. In the case of
14359 something like:
14361 template <class T>
14362 struct S {
14363 static T t();
14364 void f(T = t());
14365 };
14367 we must be careful to do name lookup in the scope of S<T>,
14368 rather than in the current class. */
14372 /* So in_immediate_context knows this is a default argument. */
14376 /* The default argument expression may cause implicitly defined
14377 member functions to be synthesized, which will result in garbage
14378 collection. We must treat this situation as if we were within
14379 the body of function so as to avoid collecting live data on the
14380 stack. */
14387 /* Make sure the default argument is reasonable. */
14404 }
14406 /* Substitute into all the default arguments for FN. */
14408 static void
14410 {
14411 tree arg;
14412 tree tmpl_args;
14416 /* If this function is not yet instantiated, we certainly don't need
14417 its default arguments. */
14420 /* Don't do this again for clones. */
14426 arg;
14432 complain);
14433 }
14435 /* Hash table mapping a FUNCTION_DECL to its dependent explicit-specifier. */
14438 /* Store a pair to EXPLICIT_SPECIFIER_MAP. */
14440 void
14442 {
14447 }
14449 /* Lookup an element in EXPLICIT_SPECIFIER_MAP. */
14451 tree
14453 {
14455 }
14457 /* Given T, a FUNCTION_TYPE or METHOD_TYPE, construct and return a corresponding
14458 FUNCTION_TYPE or METHOD_TYPE whose return type is RETURN_TYPE, argument types
14459 are ARG_TYPES, and exception specification is RAISES, and otherwise is
14460 identical to T. */
14462 static tree
14465 tsubst_flags_t complain)
14466 {
14469 tree new_type;
14471 {
14474 }
14475 else
14476 {
14478 /* Don't pick up extra function qualifiers from the basetype. */
14481 {
14482 /* [temp.deduct]
14484 Type deduction may fail for any of the following
14485 reasons:
14487 -- Attempting to create "pointer to member of T" when T
14488 is not a class type. */
14491 r);
14493 }
14497 }
14505 }
14507 /* Check if the function type of DECL, a FUNCTION_DECL, agrees with the type of
14508 each of its formal parameters. If there is a disagreement then rebuild
14509 DECL's function type according to its formal parameter types, as part of a
14510 resolution for Core issues 1001/1322. */
14512 static void
14514 {
14517 {
14520 {
14524 {
14527 }
14531 }
14532 }
14543 {
14548 }
14550 {
14560 }
14568 }
14570 /* Subroutine of tsubst_decl for the case when T is a FUNCTION_DECL. */
14572 static tree
14575 {
14580 /* Nobody should be tsubst'ing into non-template functions. */
14585 {
14588 }
14590 {
14591 /* If T is not dependent, just return it. */
14596 /* A non-templated friend doesn't get DECL_TEMPLATE_INFO. */
14600 /* Calculate the most general template of which R is a
14601 specialization. */
14604 /* We're substituting a lambda function under tsubst_lambda_expr but not
14605 directly from it; find the matching function we're already inside.
14606 But don't do this if T is a generic lambda with a single level of
14607 template parms, as in that case we're doing a normal instantiation. */
14613 /* Calculate the complete set of arguments used to
14614 specialize R. */
14616 {
14618 (DECL_TEMPLATE_RESULT
14624 /* Check to see if we already have this specialization. */
14627 /* The spec for these args might be a partial instantiation of the
14628 template, but here what we want is the FUNCTION_DECL. */
14630 }
14631 else
14633 }
14634 else
14635 {
14636 /* This special case arises when we have something like this:
14638 template <class T> struct S {
14639 friend void f<int>(int, double);
14640 };
14642 Here, the DECL_TI_TEMPLATE for the friend declaration
14643 will be an IDENTIFIER_NODE. We are being called from
14644 tsubst_friend_function, and we want only to create a
14645 new decl (R) with appropriate types so that we can call
14646 determine_specialization. */
14647 friend_case:
14650 }
14657 /* If this is a static or xobj lambda, remove the 'this' pointer added in
14658 tsubst_lambda_expr now that we know the closure type. */
14671 /* If we hit excessive deduction depth, the type is bogus even if
14672 it isn't error_mark_node, so don't build a decl. */
14676 /* We do NOT check for matching decls pushed separately at this
14677 point, as they may not represent instantiations of this
14678 template, and in any case are considered separate under the
14679 discrete model. */
14683 /* Clear out the mangled name and RTL for the instantiation. */
14686 /* Leave DECL_INITIAL set on deleted instantiations. */
14692 /* Handle explicit(dependent-expr). */
14694 {
14702 else
14703 {
14706 }
14707 }
14709 /* OpenMP UDRs have the only argument a reference to the declared
14710 type. We want to diagnose if the declared type is a reference,
14711 which is invalid, but as references to references are usually
14712 quietly merged, diagnose it here. */
14714 {
14715 tree argtype
14720 "reference type %qT in "
14724 argtype);
14725 }
14728 /* Type-conversion operator. Reconstruct the name, in
14729 case it's the name of one of the template's parameters. */
14739 {
14744 }
14753 /* If this is an instantiation of a function with internal
14754 linkage, we already know what object file linkage will be
14755 assigned to the instantiation. */
14764 /* We'll re-clone as appropriate in instantiate_template. */
14767 /* If we aren't complaining now, return on error before we register
14768 the specialization so that we'll complain eventually. */
14774 /* If we are looking at an xobj lambda, we might need to check the type of
14775 its xobj parameter. */
14777 {
14784 /* If a lambda has an empty capture clause, an xobj parameter of
14787 /* If we are coming from tsubst_lambda_expr we might not have
14788 substituted into our xobj parameter yet. We can't error out until
14789 we know what the type really is so do nothing...
14790 ...but if we are instantiating the call op for real and we don't
14791 have a real type then something has gone incredibly wrong. */
14793 else
14794 {
14795 /* We have a lambda with captures, and know the type of the xobj
14796 parameter, time to check it. */
14799 {
14800 /* This error does not emit when the lambda's call operator
14801 template is instantiated by taking its address, such as in
14802 the following case:
14804 auto f = [x = 0](this auto&&){};
14805 int (*fp)(int&) = &decltype(f)::operator();
14807 It only emits when explicitly calling the call operator with
14808 an explicit template parameter:
14810 template<typename T>
14811 struct S : T {
14812 using T::operator();
14813 operator int() const {return {};}
14814 };
14816 auto s = S{[x = 0](this auto&&) {}};
14817 s.operator()<int>();
14819 This is due to resolve_address_of_overloaded_function being
14820 deficient at reporting candidates when overload resolution
14821 fails.
14823 This diagnostic will be active in the first case if/when
14824 resolve_address_of_overloaded_function is fixed to properly
14825 emit candidates upon failure to resolve to an overload. */
14830 }
14831 }
14832 }
14834 /* Associate the constraints directly with the instantiation. We
14835 don't substitute through the constraints; that's only done when
14836 they are checked. */
14849 /* Set up the DECL_TEMPLATE_INFO for R. There's no need to do
14850 this in the special friend case mentioned above where
14851 GEN_TMPL is NULL. */
14853 {
14859 {
14860 tree new_r
14863 /* We instantiated this while substituting into
14864 the type earlier (template/friend54.C). */
14866 }
14868 /* We're not supposed to instantiate default arguments
14869 until they are called, for a template. But, for a
14870 declaration like:
14872 template <class T> void f ()
14873 { extern void g(int i = T()); }
14875 we should do the substitution when the template is
14876 instantiated. We handle the member function case in
14877 instantiate_class_template since the default arguments
14878 might refer to other members of the class. */
14883 }
14885 {
14888 }
14889 else
14892 /* Copy the list of befriending classes. */
14896 {
14900 }
14903 {
14907 /* If this is an instantiation of a member template, clone it.
14908 If it isn't, that'll be handled by
14909 clone_constructors_and_destructors. */
14912 }
14918 /* Possibly limit visibility based on template args. */
14921 {
14925 }
14940 }
14942 /* Subroutine of tsubst_decl for the case when T is a TEMPLATE_DECL. */
14944 static tree
14947 {
14948 /* We can get here when processing a member function template,
14949 member class template, or template template parameter. */
14952 tree spec;
14953 tree tmpl_args;
14955 tree r;
14959 {
14960 /* Template template parameter is treated here. */
14964 /* If we get a real template back, return it. This can happen in
14965 the context of most_specialized_partial_spec. */
14968 else
14969 /* The new TEMPLATE_DECL was built in
14970 reduce_template_parm_level. */
14973 }
14976 {
14977 /* We might already have an instance of this template.
14978 The ARGS are for the surrounding class type, so the
14979 full args contain the tsubst'd args for the context,
14980 plus the innermost args from the template decl. */
14984 /* Because this is a template, the arguments will still be
14985 dependent, even after substitution. If
14986 PROCESSING_TEMPLATE_DECL is not set, the dependency
14987 predicates will short-circuit. */
14995 /* If this is a default template template argument,
14996 tsubst might not have changed anything. */
15003 {
15005 /* Type partial instantiations are stored as the type by
15006 lookup_template_class_1, not here as the template. */
15011 }
15012 }
15014 /* Make a new template decl. It will be similar to the
15015 original, but will record the current template arguments.
15016 We also create a new function declaration, which is just
15017 like the old one, but points to this new template, rather
15018 than the old one. */
15023 // Build new template info linking to the original template decl.
15025 {
15028 }
15029 else
15032 /* The template parameters for this new template are all the
15033 template parameters for the old template, except the
15034 outermost level of parameters. */
15037 = current_template_parms
15038 = (lambda_tparms
15039 ? lambda_tparms
15041 complain));
15049 else
15050 {
15052 {
15055 }
15058 else
15060 }
15066 {
15067 /* For a partial specialization, we need to keep pointing to
15068 the primary template. */
15070 {
15073 }
15077 }
15079 {
15082 }
15083 else
15084 {
15086 /* Set DECL_TI_ARGS to the full set of template arguments,
15087 which tsubst_function_decl / tsubst_decl didn't do due to
15088 use_spec_table=false. */
15091 }
15098 {
15099 /* Propagate module information from the decl. */
15102 /* If this is a constrained template, the above tsubst of
15103 inner can find the unconstrained template, which may have
15104 come from an import. This is ok, because we don't
15105 register this instantiation (see below). */
15107 || (TEMPLATE_PARMS_CONSTRAINTS
15109 }
15118 {
15119 /* Record this non-type partial instantiation. */
15120 /* FIXME we'd like to always register the TEMPLATE_DECL, or always
15121 the DECL_TEMPLATE_RESULT, but it seems the modules code relies
15122 on this current behavior. */
15125 else
15127 }
15130 }
15132 /* True if FN is the op() for a lambda in an uninstantiated template. */
15134 bool
15136 {
15141 }
15143 /* True if FN is the substitution (via tsubst_lambda_expr) of a function for
15144 which the above is true. */
15146 bool
15148 {
15154 }
15156 /* Return the LAMBDA_EXPR from which T was ultimately regenerated.
15157 If T is not a regenerated LAMBDA_EXPR, return T. */
15159 tree
15161 {
15165 }
15167 /* Return the set of template arguments used to regenerate the lambda T
15168 from its most general lambda. */
15170 tree
15172 {
15178 else
15180 }
15182 /* We're instantiating a variable from template function TCTX. Return the
15183 corresponding current enclosing scope. We can match them up using
15184 DECL_SOURCE_LOCATION because lambdas only ever have one source location, and
15185 the DECL_SOURCE_LOCATION for a function instantiation is updated to match
15186 the template definition in regenerate_decl_from_template. */
15188 static tree
15190 {
15193 /* We shouldn't ever need to do this for other artificial functions. */
15200 }
15202 /* Substitute the ARGS into the T, which is a _DECL. Return the
15203 result of the substitution. Issue error and warning messages under
15204 control of COMPLAIN. The flag USE_SPEC_TABLE controls if we look up
15205 and insert into the specializations table or if we can assume it's
15206 the caller's responsibility; this is used by instantiate_template
15207 to avoid doing some redundant work. */
15209 static tree
15212 {
15213 #define RETURN(EXP) do { r = (EXP); goto out; } while(0)
15214 location_t saved_loc;
15222 /* Set the filename and linenumber to improve error-reporting. */
15227 {
15236 use_spec_table);
15240 {
15248 {
15249 /* If there is a local specialization that isn't a
15250 parameter pack, it means that we're doing a "simple"
15251 substitution from inside tsubst_pack_expansion. Just
15252 return the local specialization (which will be a single
15253 parm). */
15260 /* Expand the TYPE_PACK_EXPANSION that provides the types for
15261 the parameters in this function parameter pack. */
15265 {
15268 /* Zero-length parameter packs are boring. Just substitute
15269 into the chain. */
15273 }
15274 else
15275 {
15276 /* All we did was update the type. Make a note of that. */
15279 }
15280 }
15282 /* Loop through all of the parameters we'll build. When T is
15283 a function parameter pack, LEN is the number of expanded
15284 types in EXPANDED_TYPES; otherwise, LEN is 1. */
15287 {
15294 /* We're on the Ith parameter of the function parameter
15295 pack. */
15296 {
15297 /* Get the Ith type. */
15300 /* Rename the parameter to include the index. */
15303 }
15305 /* We're dealing with a normal parameter. */
15313 {
15316 else
15319 }
15330 /* Keep track of the first new parameter we
15331 generate. That's what will be returned to the
15332 caller. */
15336 /* Build a proper chain of parameters when substituting
15337 into a function parameter pack. */
15340 }
15342 /* If cp_unevaluated_operand is set, we're just looking for a
15343 single dummy parameter, so don't keep going. */
15348 /* FIRST_R contains the start of the chain we've built. */
15350 }
15354 {
15361 {
15362 /* This field is a lambda capture pack. Return a TREE_VEC of
15363 the expanded fields to instantiate_class_template_1. */
15367 {
15370 }
15371 else
15372 {
15373 /* All we did was update the type. Make a note of that. */
15376 }
15377 }
15380 {
15383 {
15387 }
15397 /* For bit-fields, DECL_BIT_FIELD_REPRESENTATIVE gives the
15398 number of bits. */
15403 {
15404 /* Set up DECL_TEMPLATE_INFO so that we can get at the
15405 NSDMI in perform_member_init. Still set DECL_INITIAL
15406 so that we know there is one. */
15411 }
15412 /* We don't have to set DECL_CONTEXT here; it is set by
15413 finish_member_declaration. */
15422 }
15426 }
15430 /* We reach here only for member using decls. We also need to check
15431 uses_template_parms because DECL_DEPENDENT_P is not set for a
15432 using-declaration that designates a member of the current
15433 instantiation (c++/53549). */
15436 {
15437 /* True iff this using-decl was written as a pack expansion
15438 (and a pack appeared in its scope or name). If a pack
15439 appeared in both, we expand the packs separately and
15440 manually merge them. */
15445 {
15448 in_decl);
15450 }
15451 else
15457 {
15461 {
15464 }
15468 }
15469 else
15477 {
15479 {
15484 }
15486 }
15494 {
15503 {
15506 }
15510 }
15514 }
15515 else
15516 {
15519 }
15524 {
15535 {
15536 /* If this is the canonical decl, we don't have to
15537 mess with instantiations, and often we can't (for
15538 typename, template type parms and such). Note that
15539 TYPE_NAME is not correct for the above test if
15540 we've copied the type for a typedef. */
15546 }
15548 /* Check to see if we already have the specialization we
15549 need. */
15555 {
15558 {
15561 /* The context and type of an injected-class-name are
15562 the same, so we don't need to substitute both. */
15564 /* If CTX is unchanged, then T is in fact the
15565 specialization we want. That situation occurs when
15566 referencing a static data member within in its own
15567 class. We can use pointer equality, rather than
15568 same_type_p, because DECL_CONTEXT is always
15569 canonical... */
15571 /* ... unless T is a member template; in which
15572 case our caller can be willing to create a
15573 specialization of that template represented
15574 by T. */
15578 }
15581 {
15584 {
15591 }
15592 else
15594 }
15595 }
15596 else
15597 {
15599 /* Subsequent calls to pushdecl will fill this in. */
15601 /* A local variable. */
15603 /* Unless this is a reference to a static variable from an
15604 enclosing function, in which case we need to fill it in now. */
15606 {
15610 }
15612 }
15613 /* If we already have the specialization we need, there is
15614 nothing more to do. */
15616 {
15619 }
15621 /* Create a new node for the specialization we need. */
15623 {
15626 else
15636 /* Substituting the type might have recursively instantiated this
15637 same alias (c++/86171). */
15640 {
15643 }
15644 }
15649 {
15653 {
15654 /* It may seem that this case cannot occur, since:
15656 typedef void f();
15657 void g() { f x; }
15659 declares a function, not a variable. However:
15661 typedef void f();
15662 template <typename T> void g() { T t; }
15663 template void g<f>();
15665 is an attempt to declare a variable with function
15666 type. */
15668 /* R is not yet sufficiently initialized, so we
15669 just use its name. */
15672 }
15674 /* Wait until cp_finish_decl to set this again, to handle
15675 circular dependency (template/instantiate6.C). */
15680 {
15682 /* If the DECL_VALUE_EXPR is converted to the declared type,
15683 preserve the identity so that gimplify_type_sizes works. */
15689 {
15692 }
15701 else
15705 }
15709 }
15715 /* Clear out the mangled name and RTL for the instantiation. */
15721 /* The initializer must not be expanded until it is required;
15722 see [temp.inst]. */
15726 {
15732 /* Possibly limit visibility based on template args. */
15735 {
15739 }
15743 }
15746 {
15747 /* A static data member declaration is always marked
15748 external when it is declared in-class, even if an
15749 initializer is present. We mimic the non-template
15750 processing here. */
15759 }
15760 else
15761 {
15766 }
15775 /* Preserve a typedef that names a type. */
15777 {
15781 /* common_handle_aligned_attribute doesn't apply the alignment
15782 to DECL_ORIGINAL_TYPE. */
15786 }
15789 }
15794 }
15795 #undef RETURN
15797 out:
15798 /* Restore the file and line information. */
15802 }
15804 /* Substitute into the complete parameter type list PARMS. */
15806 tree
15808 tree args,
15809 tsubst_flags_t complain,
15810 tree in_decl)
15811 {
15813 }
15815 /* Substitute into the ARG_TYPES of a function type.
15816 If END is a TREE_CHAIN, leave it and any following types
15817 un-substituted. */
15819 static tree
15821 tree args,
15822 tree end,
15823 tsubst_flags_t complain,
15824 tree in_decl)
15825 {
15834 {
15835 /* For a pack expansion, perform substitution on the
15836 entire expression. Later on, we'll handle the arguments
15837 one-by-one. */
15842 /* So that we'll spin through the parameters, one by one. */
15844 else
15845 {
15846 /* We only partially substituted into the parameter
15847 pack. Our type is TYPE_PACK_EXPANSION. */
15850 }
15851 }
15852 else
15855 /* Check if a substituted type is erroneous before substituting into
15856 the rest of the chain. */
15858 {
15865 {
15867 {
15871 }
15873 }
15874 }
15876 /* We do not substitute into default arguments here. The standard
15877 mandates that they be instantiated only when needed, which is
15878 done in build_over_call. */
15881 /* Except that we do substitute default arguments under tsubst_lambda_expr,
15882 since the new op() won't have any associated template arguments for us
15883 to refer to later. */
15895 {
15899 /* Do array-to-pointer, function-to-pointer conversion, and ignore
15900 top-level qualifiers as required. */
15904 {
15905 /* We've instantiated a template before its default arguments
15906 have been parsed. This can happen for a nested template
15907 class, and is not an error unless we require the default
15908 argument in a call of this function. */
15909 remaining_arg_types
15912 remaining_arg_types);
15913 }
15914 else
15915 remaining_arg_types
15917 }
15920 }
15922 /* Substitute into a FUNCTION_TYPE or METHOD_TYPE. This routine does
15923 *not* handle the exception-specification for FNTYPE, because the
15924 initial substitution of explicitly provided template parameters
15925 during argument deduction forbids substitution into the
15926 exception-specification:
15928 [temp.deduct]
15930 All references in the function type of the function template to the
15931 corresponding template parameters are replaced by the specified tem-
15932 plate argument values. If a substitution in a template parameter or
15933 in the function type of the function template results in an invalid
15934 type, type deduction fails. [Note: The equivalent substitution in
15935 exception specifications is done only when the function is instanti-
15936 ated, at which point a program is ill-formed if the substitution
15937 results in an invalid type.] */
15939 static tree
15941 tree args,
15942 tsubst_flags_t complain,
15943 tree in_decl)
15944 {
15945 tree return_type;
15948 /* The TYPE_CONTEXT is not used for function/method types. */
15951 /* DR 1227: Mixing immediate and non-immediate contexts in deduction
15952 failure. */
15956 {
15957 /* Substitute the argument types. */
15969 {
15970 /* DR 1207: 'this' is in scope in the trailing return type. */
15972 }
15974 /* Substitute the return type. */
15978 {
15981 }
15982 }
15983 else
15984 /* Substitute the return type. */
15989 /* DR 486 clarifies that creation of a function type with an
15990 invalid return type is a deduction failure. */
15993 {
15995 {
15998 else
16000 }
16002 }
16005 {
16006 /* Substitute the argument types. */
16011 }
16013 /* Construct a new type node and return it. */
16016 }
16018 /* FNTYPE is a FUNCTION_TYPE or METHOD_TYPE. Substitute the template
16019 ARGS into that specification, and return the substituted
16020 specification. If there is no specification, return NULL_TREE. */
16022 static tree
16024 tree args,
16025 tsubst_flags_t complain,
16026 tree in_decl,
16028 {
16029 tree specs;
16030 tree new_specs;
16035 {
16036 /* A noexcept-specifier. */
16041 {
16042 /* Defer instantiation of noexcept-specifiers to avoid
16043 excessive instantiations (c++/49107). */
16046 {
16047 /* We already partially instantiated this member template,
16048 so combine the new args with the old. */
16053 }
16054 else
16055 {
16058 }
16059 }
16060 else
16061 {
16063 {
16065 args);
16067 }
16069 }
16071 /* We've instantiated a template before a noexcept-specifier
16072 contained therein has been parsed. This can happen for
16073 a nested template class:
16075 struct S {
16076 template<typename> struct B { B() noexcept(...); };
16077 struct A : B<int> { ... use B() ... };
16078 };
16080 where completing B<int> will trigger instantiating the
16081 noexcept, even though we only parse it at the end of S. */
16083 {
16086 }
16087 }
16089 {
16092 else
16094 {
16095 tree spec;
16100 {
16101 /* Expand the pack expansion type. */
16104 in_decl);
16110 else
16111 {
16112 /* We're substituting into a member template, so
16113 we got a TYPE_PACK_EXPANSION back. Add that
16114 expansion and move on. */
16118 expanded_specs,
16119 complain);
16122 }
16123 }
16126 {
16129 else
16134 complain);
16135 }
16138 }
16139 }
16141 }
16143 /* Substitute through a TREE_LIST of types or expressions, handling pack
16144 expansions. */
16146 tree
16148 {
16155 ;
16157 {
16161 }
16164 else
16172 ;
16174 {
16178 }
16181 else
16188 ;
16193 else
16204 /* Determine the number of arguments. */
16206 {
16209 }
16212 else
16216 {
16224 else
16226 }
16229 }
16231 /* Take the tree structure T and replace template parameters used
16232 therein with the argument vector ARGS. IN_DECL is an associated
16233 decl for diagnostics. If an error occurs, returns ERROR_MARK_NODE.
16234 Issue error and warning messages under control of COMPLAIN. Note
16235 that we must be relatively non-tolerant of extensions here, in
16236 order to preserve conformance; if we allow substitutions that
16237 should not be allowed, we may allow argument deductions that should
16238 not succeed, and therefore report ambiguous overload situations
16239 where there are none. In theory, we could allow the substitution,
16240 but indicate that it should have failed, and allow our caller to
16241 make sure that the right thing happens, but we don't try to do this
16242 yet.
16244 This function is used for dealing with types, decls and the like;
16245 for expressions, use tsubst_expr or tsubst_copy. */
16247 tree
16249 {
16284 /* Reuse typedefs. We need to do this to handle dependent attributes,
16285 such as attribute aligned. */
16288 {
16292 {
16293 /* DECL represents an alias template and we want to
16294 instantiate it. */
16298 }
16302 {
16306 }
16311 else
16312 /* The typedef is from a non-template context. */
16316 {
16318 r = cp_build_qualified_type
16322 }
16323 else
16324 {
16325 /* We don't have an instantiation yet, so drop the typedef. */
16330 }
16331 }
16348 {
16352 /* Fall through. */
16356 {
16357 /* Figure out what arguments are appropriate for the
16358 type we are trying to find. For example, given:
16360 template <class T> struct S;
16361 template <class T, class U> void f(T, U) { S<U> su; }
16363 and supposing that we are instantiating f<int, double>,
16364 then our ARGS will be {int, double}, but, when looking up
16365 S we only want {double}. */
16372 complain);
16374 }
16375 else
16376 /* This is not a template type, so there's nothing to do. */
16399 {
16404 /* Fix up type of the magic NOP_EXPR with TREE_SIDE_EFFECTS if
16405 needed. */
16411 /* If we're in a partial instantiation, preserve the magic NOP_EXPR
16412 with TREE_SIDE_EFFECTS that indicates this is not an integral
16413 constant expression. */
16416 {
16419 }
16422 }
16426 {
16427 /* This is either an ordinary level-less auto or a CTAD placeholder
16428 auto. These get replaced only via do_auto_deduction which, in the
16429 ordinary case, temporarily overrides its level to 1 before calling
16430 tsubst. CTAD placeholders are replaced via do_class_deduction. */
16434 /* Ordinary level-less auto has nothing to substitute. */
16437 /* Substitute the template of this CTAD placeholder. */
16444 else
16446 }
16447 /* Fall through. */
16451 {
16465 {
16468 /* See through ARGUMENT_PACK_SELECT arguments. */
16471 }
16476 {
16478 /* If ARG is an argument pack, we don't actually want to
16479 perform a substitution here, because substitutions
16480 for argument packs are only done
16481 element-by-element. We can get to this point when
16482 substituting the type of a non-type template
16483 parameter pack, when that type actually contains
16484 template parameter packs from an outer template, e.g.,
16486 template<typename... Types> struct A {
16487 template<Types... Values> struct B { };
16488 }; */
16492 {
16495 /* When building concept checks for the purpose of
16496 deducing placeholders, we can end up with wildcards
16497 where types are expected. Adjust this to the deduced
16498 value. */
16506 return cp_build_qualified_type
16508 }
16510 {
16511 /* We are processing a type constructed from a
16512 template template parameter. */
16523 /* Consider this code:
16525 template <template <class> class Template>
16526 struct Internal {
16527 template <class Arg> using Bind = Template<Arg>;
16528 };
16530 template <template <class> class Template, class Arg>
16531 using Instantiate = Template<Arg>; //#0
16533 template <template <class> class Template,
16534 class Argument>
16535 using Bind =
16536 Instantiate<Internal<Template>::template Bind,
16537 Argument>; //#1
16539 When #1 is parsed, the
16540 BOUND_TEMPLATE_TEMPLATE_PARM representing the
16541 parameter `Template' in #0 matches the
16542 UNBOUND_CLASS_TEMPLATE representing the argument
16543 `Internal<Template>::template Bind'; We then want
16544 to assemble the type `Bind<Argument>' that can't
16545 be fully created right now, because
16546 `Internal<Template>' not being complete, the Bind
16547 template cannot be looked up in that context. So
16548 we need to "store" `Bind<Argument>' for later
16549 when the context of Bind becomes complete. Let's
16550 store that in a TYPENAME_TYPE. */
16554 argvec),
16555 typename_type,
16556 complain);
16558 /* We can get a TEMPLATE_TEMPLATE_PARM here when we
16559 are resolving nested-types in the signature of a
16560 member function templates. Otherwise ARG is a
16561 TEMPLATE_DECL and is the real template to be
16562 instantiated. */
16569 complain);
16570 return cp_build_qualified_type
16572 }
16575 else
16576 /* TEMPLATE_PARM_INDEX. */
16578 }
16581 /* This can happen during the attempted tsubst'ing in
16582 unify. This means that we don't yet have any information
16583 about the template parameter in question. */
16586 /* Early in template argument deduction substitution, we don't
16587 want to reduce the level of 'auto', or it will be confused
16588 with a normal template parm in subsequent deduction.
16589 Similarly, don't reduce the level of template parameters to
16590 avoid mismatches when deducing their types. */
16594 /* If we get here, we must have been looking at a parm for a
16595 more deeply nested template. Make a new version of this
16596 template parameter, but with a lower level. */
16599 {
16604 {
16607 }
16613 /* Cache lowering a type parameter or a simple template
16614 template parameter. */
16618 {
16630 /* Propagate constraints on placeholders since they are
16631 only instantiated during satisfaction. */
16636 else
16638 }
16646 {
16648 /* We might need to substitute into the types of non-type
16649 template parameters. This also lowers the level of
16650 the ttp appropriately. */
16660 complain);
16663 }
16666 /* OK, now substitute the type of the non-type parameter. We
16667 couldn't do it earlier because it might be an auto parameter,
16668 and we wouldn't need to if we had an argument. */
16677 }
16680 }
16686 /* We should never be tsubsting a binfo. */
16690 /* A vector of template arguments. */
16696 {
16700 /* [temp.deduct]
16702 Type deduction may fail for any of the following
16703 reasons:
16705 -- Attempting to create a pointer to reference type.
16706 -- Attempting to create a reference to a reference type or
16707 a reference to void.
16709 Core issue 106 says that creating a reference to a reference
16710 during instantiation is no longer a cause for failure. We
16711 only enforce this check in strict C++98 mode. */
16715 {
16718 /* We keep track of the last time we issued this error
16719 message to avoid spewing a ton of messages during a
16720 single bad template instantiation. */
16723 {
16728 else
16731 }
16734 }
16738 {
16740 {
16743 type);
16744 else
16746 type);
16747 }
16749 }
16751 {
16755 }
16757 /* In C++0x, during template argument substitution, when there is an
16758 attempt to create a reference to a reference type, reference
16759 collapsing is applied as described in [14.3.1/4 temp.arg.type]:
16761 "If a template-argument for a template-parameter T names a type
16762 that is a reference to a type A, an attempt to create the type
16763 'lvalue reference to cv T' creates the type 'lvalue reference to
16764 A,' while an attempt to create the type type rvalue reference to
16765 cv T' creates the type T"
16766 */
16767 r = cp_build_reference_type
16770 else
16775 /* Will this ever be needed for TYPE_..._TO values? */
16779 }
16781 {
16784 {
16785 /* [temp.deduct]
16787 Type deduction may fail for any of the following
16788 reasons:
16790 -- Attempting to create "pointer to member of T" when T
16791 is not a class type. */
16795 }
16797 {
16801 }
16803 {
16807 }
16810 {
16811 /* The type of the implicit object parameter gets its
16812 cv-qualifiers from the FUNCTION_TYPE. */
16813 tree memptr;
16814 tree method_type
16819 complain);
16820 }
16821 else
16824 complain);
16825 }
16828 {
16829 tree fntype;
16830 tree specs;
16835 /* Substitute the exception specification. */
16843 }
16845 {
16850 /* As an optimization, we avoid regenerating the array type if
16851 it will obviously be the same as T. */
16855 /* These checks should match the ones in create_array_type_for_decl.
16857 [temp.deduct]
16859 The deduction may fail for any of the following reasons:
16861 -- Attempting to create an array with an element type that
16862 is void, a function type, or a reference type, or [DR337]
16863 an abstract class type. */
16869 {
16873 }
16886 {
16889 }
16892 }
16895 {
16898 {
16901 in_decl);
16906 {
16911 }
16913 }
16914 else
16917 in_decl);
16927 {
16931 }
16933 {
16934 /* Normally, make_typename_type does not require that the CTX
16935 have complete type in order to allow things like:
16937 template <class T> struct S { typename S<T>::X Y; };
16939 But, such constructs have already been resolved by this
16940 point, so here CTX really should have complete type, unless
16941 it's a partial instantiation. */
16944 }
16946 /* FIXME: TYPENAME_IS_CLASS_P conflates 'class' vs 'struct' vs 'union'
16947 tags. TYPENAME_TYPE should probably remember the exact tag that
16948 was written. */
16949 enum tag_types tag_type
16959 {
16962 }
16965 {
16967 {
16971 else
16973 }
16975 {
16979 else
16981 }
16982 }
16984 return cp_build_qualified_type
16986 }
16989 {
17003 }
17006 {
17007 tree type;
17021 complain);
17022 }
17025 {
17026 tree type;
17043 else
17044 {
17048 /* In a template ~id could be either a complement expression
17049 or an unqualified-id naming a destructor; if instantiating
17050 it produces an expression, it's not an id-expression or
17051 member access. */
17054 }
17059 }
17062 {
17066 else
17073 }
17093 /* We should use one of the expression tsubsts for these codes. */
17099 }
17100 }
17102 /* Convenience wrapper over tsubst for substituting into the LHS
17103 of the :: scope resolution operator. */
17105 static tree
17107 {
17110 }
17112 /* Convenience wrapper over tsubst for substituting into an id-expression
17113 without resolving its terminal name. */
17115 static tree
17117 {
17119 }
17121 /* OLDFNS is a lookup set of member functions from some class template, and
17122 NEWFNS is a lookup set of member functions from NEWTYPE, a specialization
17123 of that class template. Return the subset of NEWFNS which are
17124 specializations of a function from OLDFNS. */
17126 static tree
17128 {
17129 /* Record all member functions from the old lookup set OLDFNS into
17130 VISIBLE_SET. */
17134 {
17136 {
17137 /* Imprecisely handle dependent using-decl by keeping all members
17138 in the new lookup set that are defined in a base class, i.e.
17139 members that could plausibly have been introduced by this
17140 dependent using-decl.
17141 FIXME: Track which members are introduced by a dependent
17142 using-decl precisely, perhaps by performing another lookup
17143 from the substituted USING_DECL_SCOPE. */
17146 }
17147 else
17149 }
17151 /* Returns true iff (a less specialized version of) FN appeared in
17152 the old lookup set OLDFNS. */
17155 /* FN is a member function from a base class, introduced via a
17156 using-decl; if it might have been introduced by a dependent
17157 using-decl then just conservatively keep it, otherwise look
17158 in the old lookup set for FN exactly. */
17161 /* FN is a member function template from the current class;
17162 look in the old lookup set for the TEMPLATE_DECL from which
17163 it was specialized. */
17165 else
17166 /* FN is a non-template member function from the current class;
17167 look in the old lookup set for the FUNCTION_DECL from which
17168 it was specialized. */
17171 };
17176 {
17179 }
17183 /* Filter out from NEWFNS the member functions that weren't
17184 previously visible according to OLDFNS. */
17189 {
17191 filtered_size++;
17192 }
17198 }
17200 /* tsubst a BASELINK. OBJECT_TYPE, if non-NULL, is the type of the
17201 expression on the left-hand side of the "." or "->" operator. We
17202 only do the lookup if we had a dependent BASELINK. Otherwise we
17203 adjust it onto the instantiated heirarchy. */
17205 static tree
17208 {
17220 {
17227 }
17235 {
17240 /* See maybe_dependent_member_ref. */
17242 {
17245 template_args);
17248 }
17251 /* Treat as-if non-dependent below. */
17256 complain);
17258 {
17259 /* Filter out from the new lookup set those functions which didn't
17260 appear in the original lookup set (in a less specialized form).
17261 This is needed to preserve the consistency of member lookup
17262 performed in an incomplete-class context, within which
17263 later-declared members ought to remain invisible. */
17266 binfo_type);
17268 }
17271 {
17277 }
17280 }
17281 else
17282 {
17283 /* We're going to overwrite pieces below, make a duplicate. */
17287 {
17288 /* The decl we found was from non-dependent scope, but we still need
17289 to update the binfos for the instantiated qualifying_scope. */
17293 }
17294 }
17296 /* If lookup found a single function, mark it as used at this point.
17297 (If lookup found multiple functions the one selected later by
17298 overload resolution will be marked as used at that point.) */
17300 {
17306 /* We might have instantiated an auto function. */
17308 }
17311 {
17312 /* Add back the template arguments, if present. */
17317 /* Update the conversion operator type. */
17319 }
17325 {
17327 qualifying_scope,
17328 object_type);
17330 /* We need to call adjust_result_of_qualified_name_lookup in case the
17331 destructor names a base class, but we unset BASELINK_QUALIFIED_P
17332 so that we still get virtual function binding. */
17334 }
17337 }
17339 /* Like tsubst_expr for a SCOPE_REF, given by QUALIFIED_ID. DONE is
17340 true if the qualified-id will be a postfix-expression in-and-of
17341 itself; false if more of the postfix-expression follows the
17342 QUALIFIED_ID. ADDRESS_P is true if the qualified-id is the operand
17343 of "&". */
17345 static tree
17349 {
17350 tree expr;
17351 tree scope;
17352 tree name;
17354 tree template_args;
17359 /* Figure out what name to look up. */
17362 {
17371 }
17372 else
17373 {
17376 }
17378 /* Substitute into the qualifying scope. When there are no ARGS, we
17379 are just trying to simplify a non-dependent expression. In that
17380 case the qualifying scope may be dependent, and, in any case,
17381 substituting will not help. */
17384 {
17387 }
17388 else
17392 {
17394 /* We built one in tsubst_baselink. */
17396 else
17397 {
17400 template_args);
17402 QUALIFIED_NAME_IS_TEMPLATE
17404 }
17407 }
17410 {
17412 {
17413 /* A BIT_NOT_EXPR is used to represent a destructor. */
17415 {
17419 }
17420 else
17423 }
17424 else
17428 {
17430 {
17431 auto_diagnostic_group d;
17435 }
17437 }
17438 }
17441 {
17445 /* Remember that there was a reference to this entity. */
17448 }
17451 {
17457 }
17460 {
17463 complain);
17464 else
17466 }
17472 {
17473 expr = (adjust_result_of_qualified_name_lookup
17475 expr = (finish_qualified_id_expr
17479 }
17481 /* Expressions do not generally have reference type. */
17483 /* However, if we're about to form a pointer-to-member, we just
17484 want the referenced member referenced. */
17494 }
17496 /* tsubst the initializer for a VAR_DECL. INIT is the unsubstituted
17497 initializer, DECL is the substituted VAR_DECL. Other arguments are as
17498 for tsubst. */
17500 static tree
17503 {
17512 {
17514 {
17516 {
17521 }
17522 }
17524 {
17525 /* If we had an initializer but it
17526 instantiated to nothing,
17527 value-initialize the object. This will
17528 only occur when the initializer was a
17529 pack expansion where the parameter packs
17530 used in that expansion were of length
17531 zero. */
17537 }
17538 }
17541 }
17543 /* If T is a reference to a dependent member of the current instantiation C and
17544 we are trying to refer to that member in a partial instantiation of C,
17545 return a SCOPE_REF; otherwise, return NULL_TREE.
17547 This can happen when forming a C++17 deduction guide, as in PR96199. */
17549 static tree
17551 tree in_decl)
17552 {
17569 {
17578 complain);
17579 }
17584 {
17590 }
17593 {
17596 /* The TYPE_DECL for a typename has DECL_CONTEXT of the typename
17597 scope, but it doesn't need to be rewritten again. */
17601 }
17605 else
17608 }
17610 /* Helper function for tsubst_omp_clauses, used for instantiation of
17611 OMP_CLAUSE_DECL of clauses. */
17613 static tree
17616 {
17620 /* Handle OpenMP iterators. */
17624 {
17625 tree ret;
17628 else
17629 {
17633 {
17647 }
17651 }
17655 }
17657 /* Handle an OpenMP array section represented as a TREE_LIST (or
17658 OMP_CLAUSE_DOACROSS_KIND). An OMP_CLAUSE_DOACROSS (with a depend
17659 kind of OMP_CLAUSE_DOACROSS_SINK) can also be represented as a
17660 TREE_LIST. We can handle it exactly the same as an array section
17661 (purpose, value, and a chain), even though the nomenclature
17662 (low_bound, length, etc) is different. */
17664 {
17665 tree low_bound
17678 }
17680 {
17681 tree low_bound
17684 in_decl);
17692 length);
17693 }
17695 /* Undo convert_from_reference tsubst_expr could have called. */
17701 }
17703 /* Like tsubst_copy, but specifically for OpenMP clauses. */
17705 static tree
17708 {
17714 {
17720 {
17723 {
17729 }
17730 /* FALLTHRU */
17760 /* FALLTHRU */
17793 in_decl);
17798 in_decl);
17804 {
17807 {
17814 }
17815 else
17817 }
17844 {
17847 }
17852 else
17884 }
17887 {
17904 /* tsubst_expr on SCOPE_REF results in returning
17905 finish_non_static_data_member result. Undo that here. */
17909 {
17914 {
17918 CASE_CONVERT:
17927 /* FALLTHRU */
17931 }
17932 }
17938 {
17941 {
17944 }
17945 }
17949 }
17950 }
17954 {
17959 {
17962 }
17963 }
17965 }
17967 /* Like tsubst_expr, but unshare TREE_LIST nodes. */
17969 static tree
17971 tree in_decl)
17972 {
17973 #define RECUR(t) tsubst_copy_asm_operands (t, args, complain, in_decl)
17991 {
17994 else
17995 {
17999 }
18000 }
18005 #undef RECUR
18006 }
18008 /* Used to temporarily communicate the list of #pragma omp parallel
18009 clauses to #pragma omp for instantiation if they are combined
18010 together. */
18015 cp_decomp *);
18017 /* Substitute one OMP_FOR iterator. */
18019 static bool
18023 {
18024 #define RECUR(NODE) \
18025 tsubst_stmt ((NODE), args, complain, in_decl)
18037 {
18040 {
18044 {
18053 else
18055 {
18057 {
18063 }
18066 }
18067 }
18068 }
18072 }
18074 {
18075 /* We need to jump through some hoops to handle declarations in the
18076 init-statement, since we might need to handle auto deduction,
18077 but we need to keep control of initialization. */
18081 }
18082 else
18083 {
18085 {
18088 {
18092 {
18096 CASE_CONVERT:
18104 {
18107 }
18108 /* FALLTHRU */
18112 }
18113 }
18114 }
18115 else
18117 }
18119 {
18125 }
18126 else
18130 {
18136 NULL_TREE);
18137 else
18139 }
18142 {
18150 {
18155 }
18158 }
18168 {
18170 {
18171 /* Declare the variable, but don't let that initialize it. */
18176 }
18179 {
18183 {
18192 }
18193 else
18197 {
18202 }
18203 else
18207 }
18213 }
18216 {
18217 /* Declare and initialize the variable. */
18220 }
18222 {
18227 {
18229 {
18235 {
18238 /* Move lastprivate (decl) clause to OMP_FOR_CLAUSES. */
18243 }
18246 {
18248 decl);
18250 }
18253 {
18255 decl);
18257 }
18258 else
18260 }
18263 }
18265 {
18268 ? OMP_CLAUSE_LASTPRIVATE
18273 {
18276 }
18277 }
18278 }
18281 {
18285 }
18286 else
18290 {
18301 {
18309 }
18310 else
18316 {
18322 }
18326 {
18334 }
18335 else
18341 }
18350 #undef RECUR
18351 }
18353 /* Helper function of tsubst_expr, find OMP_TEAMS inside
18354 of OMP_TARGET's body. */
18356 static tree
18358 {
18361 {
18370 }
18372 }
18374 /* Helper function for tsubst_expr. For decomposition declaration
18375 artificial base DECL, which is tsubsted PATTERN_DECL, tsubst
18376 also the corresponding decls representing the identifiers
18377 of the decomposition declaration. Return DECL if successful
18378 or error_mark_node otherwise, set *FIRST to the first decl
18379 in the list chained through DECL_CHAIN and *CNT to the number
18380 of such decls. */
18382 static tree
18385 {
18390 decl2
18394 {
18396 {
18399 }
18411 else
18412 {
18416 }
18423 {
18426 }
18427 else
18429 }
18432 }
18434 /* Return the proper local_specialization for init-capture pack DECL. */
18436 static tree
18438 {
18439 /* We handle normal pack captures by forwarding to the specialization of the
18440 captured parameter. We can't do that for pack init-captures; we need them
18441 to have their own local_specialization. We created the individual
18442 VAR_DECLs (if any) under build_capture_proxy, and we need to collect them
18443 when we process the DECL_EXPR for the pack init-capture in the template.
18444 So, how do we find them? We don't know the capture proxy pack when
18445 building the individual resulting proxies, and we don't know the
18446 individual proxies when instantiating the pack. What we have in common is
18447 the FIELD_DECL.
18449 So...when we instantiate the FIELD_DECL, we stick the result in
18450 local_specializations. Then at the DECL_EXPR we look up that result, see
18451 how many elements it has, synthesize the names, and look them up. */
18465 {
18470 }
18472 {
18477 else
18479 }
18481 }
18483 /* T is an operand of a template tree being substituted. Return whether
18484 T is dependent such that we should suppress some warnings that would
18485 make sense if the substituted expression were written directly, like
18486 template <int I> bool f() { return I == 2; }
18487 We don't want to warn when instantiating f that comparing two constants
18488 always has the same value.
18490 This is a more limited concept of dependence than instantiation-dependent;
18491 here we don't care whether substitution could fail. */
18493 static bool
18495 {
18504 }
18506 /* A superset of tsubst_expr that also handles statement trees. */
18508 static tree
18510 {
18511 #define RETURN(EXP) do { r = (EXP); goto out; } while(0)
18512 #define RECUR(NODE) \
18513 tsubst_stmt ((NODE), args, complain, in_decl)
18516 tree r;
18517 location_t loc;
18529 {
18531 {
18535 }
18554 else
18567 {
18572 }
18576 {
18578 tree init;
18584 {
18587 {
18591 {
18596 }
18598 }
18599 else
18600 {
18601 /* This is a non-dependent using-decl, and we'll have
18602 used the names it found during template parsing. We do
18603 not want to do the lookup again, because we might not
18604 find the things we found then. */
18607 /* We still need to push the bindings so that we can look up
18608 this name later. */
18611 }
18612 }
18615 {
18616 /* We're in tsubst_lambda_expr, we've already inserted a new
18617 capture proxy, so look it up and register it. */
18618 tree inst;
18620 {
18624 }
18626 {
18627 inst = (retrieve_local_specialization
18631 }
18632 else
18637 }
18644 /* Don't copy the old closure; we'll create a new one in
18645 tsubst_lambda_expr. */
18647 else
18648 {
18652 {
18653 /* By marking the declaration as instantiated, we avoid
18654 trying to instantiate it. Since instantiate_decl can't
18655 handle local variables, and since we've already done
18656 all that needs to be done, that's the right thing to
18657 do. */
18662 /* Anonymous aggregates are a special case. */
18665 {
18668 {
18672 }
18674 }
18679 {
18687 }
18688 else
18689 {
18702 {
18708 }
18713 const_init = (DECL_INITIALIZED_BY_CONSTANT_EXPRESSION_P
18716 /* In a non-template function, VLA type declarations are
18717 handled in grokdeclarator; for templates, handle them
18718 now. */
18722 {
18726 asmspec_tree
18730 }
18733 decomp);
18734 }
18735 }
18736 }
18739 }
18749 {
18753 }
18758 {
18759 /* Construct another range_for, if this is not a final
18760 substitution (for inside a generic lambda of a
18761 template). Otherwise convert to a regular for. */
18763 stmt = (processing_template_decl
18774 {
18778 }
18782 unroll
18784 unroll);
18786 {
18793 }
18794 else
18803 }
18810 {
18814 }
18820 {
18824 }
18836 {
18842 }
18845 {
18846 /* We're partially instantiating a generic lambda, but the condition
18847 of the constexpr if is still dependent. Don't substitute into the
18848 branches now, just remember the template arguments. */
18857 }
18861 {
18866 }
18867 else
18868 {
18876 }
18882 {
18892 }
18900 else
18908 else
18929 {
18935 {
18940 }
18941 }
18945 {
18949 {
18952 }
18955 }
18961 /* Computed goto's must be tsubst'd into. On the other hand,
18962 non-computed gotos must not be; the identifier in question
18963 will have no binding. */
18965 else
18971 {
18988 }
18993 {
18998 }
18999 else
19000 {
19005 else
19012 else
19018 else
19020 }
19024 {
19028 {
19030 /* Prevent instantiate_decl from trying to instantiate
19031 this variable. We've already done all that needs to be
19032 done. */
19035 }
19040 }
19046 /* This is a partial instantiation, try again when full. */
19049 {
19050 /* Local classes are not independent templates; they are
19051 instantiated along with their containing function. And this
19052 way we don't have to deal with pushing out of one local class
19053 to instantiate a member of another local class. */
19054 /* Closures are handled by the LAMBDA_EXPR. */
19070 }
19074 {
19091 }
19120 {
19127 }
19145 {
19159 in_decl);
19161 {
19168 }
19184 {
19187 }
19191 {
19193 any_range_for
19197 else
19198 {
19205 }
19206 }
19210 {
19220 }
19221 else
19226 else
19233 else
19234 {
19242 }
19245 {
19246 /* P2718R0 - Add CLEANUP_POINT_EXPR so that temporaries in
19247 for-range-initializer whose lifetime is extended are destructed
19248 here. */
19252 }
19255 t));
19263 {
19271 }
19272 }
19278 /* FALLTHRU */
19288 in_decl);
19290 {
19295 }
19296 else
19297 {
19301 }
19306 {
19308 "%<#pragma omp critical%> with %<hint%> clause requires "
19311 }
19322 {
19325 {
19330 }
19331 else
19332 {
19336 }
19338 }
19339 else
19341 OMP_CLAUSE_DEPEND_INVALID,
19350 ? C_ORT_ACC
19369 {
19372 /* For combined target teams, ensure the num_teams and
19373 thread_limit clause expressions are evaluated on the host,
19374 before entering the target construct. */
19383 {
19386 tf_none);
19393 OMP_CLAUSE_FIRSTPRIVATE);
19397 }
19398 }
19435 {
19439 }
19440 else
19452 /* FALLTHRU */
19470 {
19476 {
19479 }
19481 {
19485 {
19488 }
19493 }
19494 else
19495 {
19498 }
19503 }
19504 else
19505 {
19512 {
19515 }
19518 {
19523 {
19526 }
19528 {
19532 {
19535 }
19540 }
19541 else
19542 {
19545 }
19549 }
19550 else
19551 {
19555 }
19559 }
19563 {
19569 {
19573 {
19578 }
19582 }
19583 else
19584 {
19589 }
19590 }
19594 {
19598 }
19611 /* If the first operand was a statement, we're done with it. */
19616 complain));
19622 {
19623 /* Although ANNOTATE_EXPR is an expression, it can only appear in
19624 WHILE_COND, DO_COND or FOR_COND expressions, which are tsubsted
19625 using tsubst_stmt rather than tsubst_expr and can contain
19626 DECL_EXPRs. */
19633 op3);
19636 }
19642 }
19645 out:
19648 #undef RECUR
19649 #undef RETURN
19650 }
19652 /* Instantiate the special body of the artificial DECL_OMP_DECLARE_REDUCTION
19653 function. For description of the body see comment above
19654 cp_parser_omp_declare_reduction_exprs. */
19656 static void
19658 {
19664 tree_stmt_iterator tsi;
19675 {
19682 /* tsubsting a local var_decl leaves DECL_CONTEXT null, as we
19683 expect to be pushing it. */
19695 }
19697 {
19717 }
19718 }
19720 /* T is a postfix-expression that is not being used in a function
19721 call. Return the substituted version of T. */
19723 static tree
19725 tsubst_flags_t complain,
19726 tree in_decl)
19727 {
19731 else
19735 }
19737 /* Subroutine of tsubst_lambda_expr: add the FIELD/INIT capture pair to the
19738 LAMBDA_EXPR_CAPTURE_LIST passed in LIST. Do deduction for a previously
19739 dependent init-capture. EXPLICIT_P is true if the original list had
19740 explicit captures. */
19742 static void
19744 tsubst_flags_t complain)
19745 {
19747 {
19750 {
19754 }
19761 }
19764 }
19766 /* T is a LAMBDA_EXPR. Generate a new LAMBDA_EXPR for the current
19767 instantiation context. Instantiating a pack expansion containing a lambda
19768 might result in multiple lambdas all based on the same lambda in the
19769 template. */
19771 tree
19773 {
19780 {
19781 /* Defer templated substitution into a lambda-expr if we lost the
19782 necessary template context. This may happen for a lambda-expr
19783 used as a default template argument.
19785 Defer dependent substitution as well so that we don't prematurely
19786 lower the level of a deduced return type or any other auto or
19787 template parameter belonging to the lambda. */
19792 }
19804 else
19815 {
19820 else
19832 {
19833 /* For a VLA, simply tsubsting the field type won't work, we need to
19834 go through add_capture again. XXX do we want to do this for all
19835 captures? */
19836 tree name = (get_identifier
19845 }
19852 {
19853 /* Remember these for when we've pushed local_specializations. */
19856 }
19862 {
19871 complain);
19872 }
19873 else
19874 {
19880 }
19881 }
19885 {
19888 }
19893 /* If we're pushed into another scope (PR105652), fix it. */
19898 /* Do this again now that LAMBDA_EXPR_EXTRA_SCOPE is set. */
19915 {
19918 }
19921 {
19924 }
19928 else
19929 {
19930 /* The body of a lambda-expression is not a subexpression of the
19931 enclosing expression. Parms are to have DECL_CHAIN tsubsted,
19932 which would be skipped if cp_unevaluated_operand. */
19933 cp_evaluated ev;
19935 /* Fix the type of 'this'.
19936 For static and xobj member functions we use this to transport the
19937 lambda's closure type. It appears that in the regular case the
19938 object parameter is still pulled off, and then re-added again anyway.
19939 So perhaps we could do something better here? */
19943 tree inst = (oldtmpl
19948 {
19951 }
19957 /* Let finish_function set this. */
19963 else
19964 /* Still increment function_depth so that we don't GC in the
19965 middle of an expression. */
19975 /* Now record them for lookup_init_capture_pack. */
19978 {
19982 }
19988 {
19989 /* We might not partially instantiate some parts of the function, so
19990 copy these flags from the original template. */
19996 }
19998 /* [temp.deduct] A lambda-expression appearing in a function type or a
19999 template parameter is not considered part of the immediate context for
20000 the purposes of template argument deduction. */
20005 /* We already have a body block from start_lambda_function, we don't
20006 need another to confuse NRV (91217). */
20017 else
20020 /* The capture list was built up in reverse order; fix that now. */
20027 }
20029 out:
20035 }
20037 /* Subroutine of maybe_fold_fn_template_args. */
20039 static bool
20041 {
20044 {
20050 {
20053 }
20058 {
20062 }
20063 }
20066 }
20068 /* Try to do constant evaluation of any explicit template arguments in FN
20069 before overload resolution, to get any errors only once. Return true iff
20070 we didn't have any problems folding. */
20072 static bool
20074 {
20092 }
20094 /* Helper function for tsubst_expr CALL_EXPR and ARRAY_REF handling. */
20096 static void
20099 {
20102 {
20107 else
20108 {
20109 /* Expand the pack expansion and push each entry onto CALL_ARGS. */
20112 {
20117 {
20122 }
20123 }
20124 else
20125 /* A partial substitution. Add one entry. */
20127 }
20128 }
20129 }
20131 /* Like tsubst but deals with expressions and performs semantic
20132 analysis. */
20134 tree
20136 {
20137 #define RETURN(EXP) do { retval = (EXP); goto out; } while(0)
20138 #define RECUR(NODE) \
20139 tsubst_expr (NODE, args, complain, in_decl)
20142 location_t save_loc;
20151 /* N3276 decltype magic only applies to calls at the top level or on the
20152 right side of a comma. */
20156 /* This flag only applies to id-expressions at the top level, and
20157 controls resolution thereof. */
20166 {
20169 /* Fall through. */
20171 {
20172 tree decl;
20173 cp_id_kind idk;
20177 {
20180 }
20185 /* Look up the name. */
20188 /* By convention, expressions use ERROR_MARK_NODE to indicate
20189 failure, not NULL_TREE. */
20203 input_location);
20207 {
20211 }
20213 }
20216 {
20217 tree object;
20223 else
20232 {
20237 }
20240 {
20245 }
20248 {
20253 complain);
20257 }
20260 {
20263 }
20264 else
20276 {
20277 /* C++20 P0846: we can encounter an IDENTIFIER_NODE here when
20278 name lookup found nothing when parsing the template name. */
20281 }
20282 else
20284 }
20287 {
20291 {
20292 /* A type conversion to reference type will be enclosed in
20293 such an indirect ref, but the substitution of the cast
20294 will have also added such an indirect ref. */
20296 }
20297 else
20306 }
20309 {
20314 }
20317 {
20321 }
20324 {
20330 {
20335 }
20337 {
20342 }
20349 flags));
20350 }
20353 {
20359 }
20366 {
20367 tree type;
20381 {
20401 }
20404 }
20407 {
20411 }
20423 {
20426 }
20428 {
20432 }
20433 /* Fall through. */
20448 {
20455 }
20458 /* convert_like should have created an IMPLICIT_CONV_EXPR. */
20469 else
20471 in_decl);
20506 {
20507 /* If either OP0 or OP1 was value- or type-dependent, suppress
20508 warnings that depend on the range of the types involved. */
20522 tree r = build_x_binary_op
20524 op0,
20526 ? ERROR_MARK
20528 op1,
20530 ? ERROR_MARK
20539 }
20542 {
20550 }
20554 {
20559 }
20560 else
20574 {
20576 releasing_vec index_exp_list;
20579 tree r;
20585 else
20590 }
20596 {
20602 {
20606 }
20608 {
20612 }
20614 }
20619 {
20628 /* We only want to compute the number of arguments. */
20631 else
20638 {
20640 /* Set TREE_USED for the benefit of -Wunused. */
20644 }
20652 {
20655 else
20663 else
20668 }
20669 else
20671 }
20672 /* Fall through */
20675 {
20676 tree r;
20684 {
20685 /* When there are no ARGS, we are trying to evaluate a
20686 non-dependent expression from the parser. Trying to do
20687 the substitutions may not work. */
20690 }
20691 else
20692 {
20697 else
20701 }
20706 else
20711 {
20713 {
20715 {
20719 }
20720 else
20724 }
20727 }
20729 }
20732 {
20740 }
20754 {
20759 tree r = build_x_modify_expr
20763 /* TREE_NO_WARNING must be set if either the expression was
20764 parenthesized or it uses an operator such as >>= rather
20765 than plain assignment. In the former case, it was already
20766 set and must be copied. In the latter case,
20767 build_x_modify_expr sets it and it must not be reset
20768 here. */
20773 }
20778 /* Remember that there was a reference to this entity. */
20785 {
20790 tree ret;
20797 else
20798 {
20802 }
20804 /* If there was an initializer in the original tree, but it
20805 instantiated to an empty list, then we should pass a
20806 non-NULL empty vector to tell build_new that it was an
20807 empty initializer() rather than no initializer. This can
20808 only happen when the initializer is a pack expansion whose
20809 parameter packs are of length zero. */
20814 else
20815 {
20819 else
20820 {
20823 }
20824 }
20826 /* Avoid passing an enclosing decl to valid_array_size_p. */
20833 complain);
20841 }
20844 {
20850 complain));
20851 }
20854 {
20858 op0,
20862 }
20865 {
20866 tree function;
20870 tree ret;
20873 /* Internal function with no arguments. */
20877 /* When we parsed the expression, we determined whether or
20878 not Koenig lookup should be performed. */
20881 {
20884 }
20886 {
20891 }
20895 {
20897 in_decl);
20899 {
20906 }
20907 else
20910 }
20915 {
20916 /* Do nothing; calling tsubst_expr on an identifier
20917 would incorrectly perform unqualified lookup again.
20919 Note that we can also have an IDENTIFIER_NODE if the earlier
20920 unqualified lookup found a dependent local extern declaration
20921 (as per finish_call_expr); in that case koenig_p will be false
20922 and we do want to do the lookup again to find the substituted
20923 declaration. */
20928 }
20929 else
20930 {
20932 {
20938 }
20939 else
20944 /* Avoid error about taking the address of a constructor. */
20949 /* When KOENIG_P, we don't want to mark_used the callee before
20950 augmenting the overload set via ADL, so during this initial
20951 substitution we disable mark_used by setting tf_conv (68942). */
20957 }
20960 releasing_vec call_args;
20963 /* Stripped-down processing for a call in a thunk. Specifically, in
20964 the thunk template for a generic lambda. */
20966 {
20967 /* Now that we've expanded any packs, the number of call args
20968 might be different. */
20972 {
20979 }
20980 /* We aren't going to do normal overload resolution, so force the
20981 template-id to resolve. */
20984 {
20985 /* In a thunk, pass through args directly, without any
20986 conversions. */
20991 }
20993 {
20994 /* If there are no other args, just push 'this'. */
20997 else
20998 {
20999 /* Otherwise, shift the other args over to make room. */
21005 }
21006 }
21009 /* The thunk location is not interesting. */
21016 }
21018 /* We do not perform argument-dependent lookup if normal
21019 lookup finds a non-function, in accordance with the
21020 resolution of DR 218. */
21023 /* If lookup found a member function, the Koenig lookup is
21024 not appropriate, even if an unqualified-name was used
21025 to denote the function. */
21028 /* C++20 P0846: Lookup found nothing. */
21031 /* Only do this when substitution turns a dependent call
21032 into a non-dependent call. */
21044 {
21049 {
21050 /* For backwards compatibility and good diagnostics, try
21051 the unqualified lookup again if we aren't in SFINAE
21052 context. */
21058 {
21059 auto_diagnostic_group d;
21062 "and no declarations were found by "
21063 "argument-dependent lookup at the point "
21068 /* In a lambda fn, we have to be careful to not
21069 introduce new this captures. Legacy code can't
21070 be using lambdas anyway, so it's ok to be
21071 stricter. Be strict with C++20 template-id ADL too.
21072 And be strict if we're already failing anyway. */
21078 else
21082 {
21093 {
21096 "declarations in dependent base %qT are "
21102 else
21106 }
21107 else
21109 "%qD declared here, later in the "
21113 }
21116 }
21117 }
21119 {
21123 }
21124 }
21126 /* Remember that there was a reference to this entity. */
21135 /* Put back tf_decltype for the actual call. */
21140 {
21144 {
21146 "wrong number of arguments to "
21149 }
21150 else
21158 {
21160 "wrong number of arguments to "
21164 }
21168 complain);
21174 {
21176 complain);
21180 }
21185 {
21187 "wrong number of arguments to "
21190 }
21191 else
21192 {
21197 {
21200 }
21203 }
21207 /* Unsupported internal function with arguments. */
21209 }
21214 complain);
21216 /* Calls to concepts should have been previously diagnosed. */
21218 else
21221 koenig_p,
21222 complain);
21225 {
21234 {
21242 }
21244 /* This also suppresses -Wredundant-move. */
21246 }
21249 }
21252 {
21259 {
21261 {
21266 }
21267 else
21268 {
21273 }
21275 }
21276 else
21277 {
21280 }
21285 }
21288 {
21293 input_location));
21294 }
21300 {
21301 tree object;
21302 tree object_type;
21303 tree member;
21304 tree r;
21308 /* Remember that there was a reference to this entity. */
21319 else
21326 {
21329 }
21331 {
21333 complain);
21337 }
21341 {
21343 {
21348 {
21351 }
21353 {
21358 }
21359 }
21360 }
21363 {
21364 /* Lookup the template functions now that we know what the
21365 scope is. */
21372 {
21375 args);
21376 member = (adjust_result_of_qualified_name_lookup
21378 object_type));
21379 }
21380 else
21381 {
21383 input_location);
21385 }
21386 }
21390 {
21392 {
21396 else
21399 }
21401 }
21405 complain);
21409 }
21416 {
21423 tree r;
21432 /* We do not want to process the index of aggregate
21433 initializers as they are identifier nodes which will be
21434 looked up by digest_init. */
21438 {
21441 }
21446 {
21448 /* An identifier index is looked up in the type
21449 being initialized, not the current scope. */
21454 {
21455 /* Substitute into the pack expansion. */
21457 in_decl);
21461 ;
21463 /* Just move the argument into place. */
21465 else
21466 {
21467 /* Update the length of the final CONSTRUCTOR
21468 arguments vector, and note that we will need to
21469 copy.*/
21472 }
21473 }
21474 else
21476 }
21479 {
21484 {
21486 {
21491 }
21492 else
21494 }
21495 }
21503 {
21508 }
21512 }
21515 {
21518 {
21521 }
21522 else
21523 {
21526 }
21527 }
21534 tree r;
21539 {
21540 /* Local specialization will usually have been created when
21541 we instantiated the DECL_EXPR_DECL. */
21544 {
21545 /* We're in a generic lambda referencing a local extern
21546 from an outer block-scope of a non-template. */
21549 }
21550 }
21555 {
21557 {
21558 /* We get here for a use of 'this' in an NSDMI. */
21562 /* This can happen for a parameter name used later in a function
21563 declaration (such as in a late-specified return type). Just
21564 make a dummy decl, since it's only used for its type. */
21567 /* Give it the template pattern as its context; its true context
21568 hasn't been instantiated yet and this is good enough for
21569 mangling. */
21571 }
21573 {
21574 /* First try name lookup to find the instantiation. */
21577 {
21579 {
21580 /* During error-recovery we may find a non-variable,
21581 even an OVERLOAD: just bail out and avoid ICEs and
21582 duplicate diagnostics (c++/62207). */
21585 }
21587 {
21588 /* Make sure the one we found is the one we want. */
21592 }
21593 }
21597 else
21598 {
21599 /* This can happen for a variable used in a
21600 late-specified return type of a local lambda, or for a
21601 local static or constant. Building a new VAR_DECL
21602 should be OK in all those cases. */
21605 /* Avoid infinite recursion (79640). */
21608 {
21609 /* We can't call cp_finish_decl, so handle the
21610 initializer by hand. */
21625 }
21627 || processing_contract_condition
21634 }
21635 /* Remember this for subsequent uses. */
21638 }
21641 }
21642 else
21649 {
21650 /* ??? We're doing a subset of finish_id_expression here. */
21652 /* Replace an evaluated use of the thread_local variable with
21653 a call to its wrapper. */
21659 /* If the original type was a reference, we'll be wrapped in
21660 the appropriate INDIRECT_REF. */
21662 }
21666 {
21667 tree enum_type;
21668 tree v;
21675 /* Unfortunately, we cannot just call lookup_name here.
21676 Consider:
21678 template <int I> int f() {
21679 enum E { a = I };
21680 struct S { void g() { E e = a; } };
21681 };
21683 When we instantiate f<7>::S::g(), say, lookup_name is not
21684 clever enough to find f<7>::a. */
21693 /* We didn't find the name. That should never happen; if
21694 name-lookup found it during preliminary parsing, we
21695 should find it again here during instantiation. */
21698 }
21702 {
21703 tree ctx;
21708 {
21711 {
21715 }
21717 }
21718 }
21733 {
21734 /* Template template argument like the following example need
21735 special treatment:
21737 template <template <class> class TT> struct C {};
21738 template <class T> struct D {
21739 template <class U> struct E {};
21740 C<E> c; // #1
21741 };
21742 D<int> d; // #2
21744 We are processing the template argument `E' in #1 for
21745 the template instantiation #2. Originally, `E' is a
21746 TEMPLATE_DECL with `D<T>' as its DECL_CONTEXT. Now we
21747 have to substitute this with one having context `D<int>'. */
21752 }
21753 else
21754 /* Ordinary template template argument. */
21762 /* We shouldn't have built any of these during initial template
21763 generation. Instead, they should be built during instantiation
21764 in response to the saved STMT_IS_FULL_EXPR_P setting. */
21768 {
21778 }
21796 {
21797 /* Instantiate any typedefs in the type. */
21802 }
21805 {
21809 {
21812 }
21814 }
21817 /* These can sometimes show up in a partial instantiation, but never
21818 involve template parms. */
21834 /* ??? There's no point in copying it for now, but maybe some
21835 day it will contain more information, such as a pointer back
21836 to the containing function, inlined copy or so. */
21848 {
21852 }
21855 {
21856 tree object_ptr
21861 }
21868 {
21872 else
21878 }
21881 {
21890 /* If the resulting list of expression statement is empty,
21891 fold it further into void_node. */
21896 }
21899 {
21903 }
21912 else
21913 /* Recreate the PAREN_EXPR from __builtin_assoc_barrier. */
21914 {
21918 }
21921 {
21926 complain));
21927 }
21930 {
21934 }
21937 /* No need to substitute further, a RANGE_EXPR will always be built
21938 with constant operands. */
21943 {
21947 /* We need to do this here as well as in tsubst_copy so we get the
21948 other tsubst_copy_and_build semantics for a PARM_DECL operand. */
21953 /* force_paren_expr can also create a VIEW_CONVERT_EXPR. */
21956 /* Otherwise, we're dealing with a wrapper to make a C++20 template
21957 parameter object const. */
21960 {
21961 /* The template argument is not const, presumably because
21962 it is still dependent, and so not the const template parm
21963 object. */
21967 {
21968 /* Don't add a wrapper to these. */
21971 }
21972 else
21973 /* Do add a wrapper otherwise (in particular, if op is
21974 another TEMPLATE_PARM_INDEX). */
21976 }
21978 }
21981 /* Handle Objective-C++ constructs, if appropriate. */
21985 /* We shouldn't get here, but keep going if !flag_checking. */
21989 }
21991 #undef RECUR
21992 #undef RETURN
21993 out:
21996 }
21998 /* Verify that the instantiated ARGS are valid. For type arguments,
21999 make sure that the type's linkage is ok. For non-type arguments,
22000 make sure they are constants if they are integral or enumerations.
22001 Emit an error under control of COMPLAIN, and return TRUE on error. */
22003 static bool
22005 {
22009 {
22019 }
22021 {
22022 /* [basic.link]: A name with no linkage (notably, the name
22023 of a class or enumeration declared in a local scope)
22024 shall not be used to declare an entity with linkage.
22025 This implies that names with no linkage cannot be used as
22026 template arguments
22028 DR 757 relaxes this restriction for C++0x. */
22033 {
22034 /* DR 488 makes use of a type with no linkage cause
22035 type deduction to fail. */
22037 {
22040 else
22043 }
22045 }
22046 /* In order to avoid all sorts of complications, we do not
22047 allow variably-modified types as template arguments. */
22049 {
22053 }
22054 }
22055 /* Class template and alias template arguments should be OK. */
22057 ;
22058 /* A non-type argument of integral or enumerated type must be a
22059 constant. */
22064 {
22068 }
22070 }
22072 static bool
22074 {
22079 {
22082 }
22086 }
22088 /* Call mark_used on each entity within the non-type template arguments in
22089 ARGS for an instantiation of TMPL, to ensure that each such entity is
22090 considered odr-used (and therefore marked for instantiation) regardless of
22091 whether the specialization was first formed in a template context (which
22092 inhibits mark_used).
22094 This function assumes push_to_top_level has been called beforehand. */
22096 static void
22098 {
22099 /* It suffices to do this only when instantiating a primary template. */
22103 /* We already marked outer arguments when specializing the context. */
22107 {
22108 /* A (pointer/reference to) function or variable NTTP argument. */
22111 {
22117 {
22118 /* Pass tf_none to avoid duplicate diagnostics: if this call
22119 fails then an earlier call to mark_used for this argument
22120 must have also failed and emitted a diagnostic. */
22123 }
22124 }
22125 /* A class NTTP argument. */
22128 {
22131 {
22134 }
22136 };
22139 }
22140 }
22141 }
22143 /* We're out of SFINAE context now, so generate diagnostics for the access
22144 errors we saw earlier when instantiating D from TMPL and ARGS. */
22146 static void
22148 {
22160 }
22162 /* Instantiate the indicated variable, function, or alias template TMPL with
22163 the template arguments in TARG_PTR. */
22165 tree
22167 {
22171 tree fndecl;
22172 tree gen_tmpl;
22178 /* The other flags are not relevant anymore here, especially tf_partial
22179 shouldn't be set. For instance, we may be called while doing a partial
22180 substitution of a template variable, but the type of the variable
22181 template may be auto, in which case we will call do_auto_deduction
22182 in mark_used (which clears tf_partial) and the auto must be properly
22183 reduced at that time for the deduction to work. */
22191 /* If this function is a clone, handle it specially. */
22193 {
22194 tree spec;
22195 tree clone;
22197 /* Use DECL_ABSTRACT_ORIGIN because only FUNCTION_DECLs have
22198 DECL_CLONED_FUNCTION. */
22204 /* Look for the clone. */
22208 /* We should always have found the clone by now. */
22211 }
22216 /* Check to see if we already have this specialization. */
22220 /* targ_ptr only has the innermost template args, so add the outer ones
22221 from tmpl, which could be either a partial instantiation or gen_tmpl (in
22222 the case of a non-dependent call within a template definition). */
22223 targ_ptr = (add_outermost_template_args
22225 targ_ptr));
22231 || ((fndecl
22237 {
22239 {
22243 }
22245 }
22248 complain))
22251 /* We are building a FUNCTION_DECL, during which the access of its
22252 parameters and return types have to be checked. However this
22253 FUNCTION_DECL which is the desired context for access checking
22254 is not built yet. We solve this chicken-and-egg problem by
22255 deferring all checks until we have the FUNCTION_DECL. */
22258 /* Instantiation of the function happens in the context of the function
22259 template, not the context of the overload resolution we're doing. */
22261 /* If there are dependent arguments, e.g. because we're doing partial
22262 ordering, make sure processing_template_decl stays set. */
22266 {
22267 tree ctx;
22269 /* If the context of the partially instantiated template is
22270 already non-dependent, then we might as well use it. */
22272 else
22276 }
22283 {
22284 /* We need to determine if we're using a partial or explicit
22285 specialization now, because the type of the variable could be
22286 different. */
22292 {
22298 }
22299 }
22301 /* Substitute template parameters to obtain the specialization. */
22309 {
22312 }
22314 /* The DECL_TI_TEMPLATE should always be the immediate parent
22315 template, not the most general template. */
22319 {
22320 /* Now that we we've formed this variable template specialization,
22321 remember the result of most_specialized_partial_spec for it. */
22324 /* And remember if the variable was declared with []. */
22328 }
22336 /* Now we know the specialization, compute access previously
22337 deferred. Do no access control for inheriting constructors,
22338 as we already checked access for the inherited constructor. */
22341 {
22346 }
22349 /* If we've just instantiated the main entry point for a function,
22350 instantiate all the alternate entry points as well. We do this
22351 by cloning the instantiation of the main entry point, not by
22352 instantiating the template clones. */
22358 {
22360 {
22361 /* Remember to reinstantiate when we're out of SFINAE so the user
22362 can see the errors. */
22364 }
22366 }
22369 }
22371 /* Instantiate the alias template TMPL with ARGS. Also push a template
22372 instantiation level, which instantiate_template doesn't do because
22373 functions and variables have sufficient context established by the
22374 callers. */
22376 static tree
22378 {
22387 /* FIXME check for satisfaction in check_instantiated_args. */
22389 {
22391 {
22392 auto_diagnostic_group d;
22395 }
22397 }
22405 {
22406 /* Note this is also done at parse time from push_template_decl. */
22407 /* An alias template specialization can be dependent
22408 even if its underlying type is not. */
22411 /* Sometimes a dependent alias spec is equivalent to its expansion,
22412 sometimes not. So always use structural_comptypes. */
22414 }
22417 }
22419 /* PARM is a template parameter pack for FN. Returns true iff
22420 PARM is used in a deducible way in the argument list of FN. */
22422 static bool
22424 {
22427 {
22429 tree packs;
22435 {
22436 /* The template parameter pack is used in a function parameter
22437 pack. If this is the end of the parameter list, the
22438 template parameter pack is deducible. */
22441 else
22442 /* Otherwise, not. Well, it could be deduced from
22443 a non-pack parameter, but doing so would end up with
22444 a deduction mismatch, so don't bother. */
22446 }
22447 }
22448 /* The template parameter pack isn't used in any function parameter
22449 packs, but it might be used deeper, e.g. tuple<Args...>. */
22451 }
22453 /* Subroutine of fn_type_unification: check non-dependent parms for
22454 convertibility. */
22456 static int
22461 {
22462 /* Non-constructor methods need to leave a conversion for 'this', which
22463 isn't included in nargs here. */
22469 {
22475 /* For a function parameter pack that occurs at the end of the
22476 parameter-declaration-list, the type A of each remaining
22477 argument of the call is compared with the type P of the
22478 declarator-id of the function parameter pack. */
22484 /* For a function parameter pack that does not occur at the
22485 end of the parameter-declaration-list, the type of the
22486 parameter pack is a non-deduced context. */
22490 {
22498 }
22501 }
22504 }
22506 /* The FN is a TEMPLATE_DECL for a function. ARGS is an array with
22507 NARGS elements of the arguments that are being used when calling
22508 it. TARGS is a vector into which the deduced template arguments
22509 are placed.
22511 Returns either a FUNCTION_DECL for the matching specialization of FN or
22512 NULL_TREE if no suitable specialization can be found. If EXPLAIN_P is
22513 true, diagnostics will be printed to explain why it failed.
22515 If FN is a conversion operator, or we are trying to produce a specific
22516 specialization, RETURN_TYPE is the return type desired.
22518 The EXPLICIT_TARGS are explicit template arguments provided via a
22519 template-id.
22521 The parameter STRICT is one of:
22523 DEDUCE_CALL:
22524 We are deducing arguments for a function call, as in
22525 [temp.deduct.call]. If RETURN_TYPE is non-null, we are
22526 deducing arguments for a call to the result of a conversion
22527 function template, as in [over.call.object].
22529 DEDUCE_CONV:
22530 We are deducing arguments for a conversion function, as in
22531 [temp.deduct.conv].
22533 DEDUCE_EXACT:
22534 We are deducing arguments when doing an explicit instantiation
22535 as in [temp.explicit], when determining an explicit specialization
22536 as in [temp.expl.spec], or when taking the address of a function
22537 template, as in [temp.deduct.funcaddr]. */
22539 tree
22541 tree explicit_targs,
22542 tree targs,
22545 tree return_type,
22546 unification_kind_t strict,
22551 {
22552 tree parms;
22553 tree fntype;
22558 /* type_unification_real will pass back any access checks from default
22559 template argument substitution. */
22561 /* We don't have all the template args yet. */
22574 full_targs = (add_outermost_template_args
22576 targs));
22581 /* In C++0x, it's possible to have a function template whose type depends
22582 on itself recursively. This is most obvious with decltype, but can also
22583 occur with enumeration scope (c++/48969). So we need to catch infinite
22584 recursion and reject the substitution at deduction time; this function
22585 will return error_mark_node for any repeated substitution.
22587 This also catches excessive recursion such as when f<N> depends on
22588 f<N-1> across all integers, and returns error_mark_node for all the
22589 substitutions back up to the initial one.
22591 This is, of course, not reentrant. */
22600 {
22601 /* [temp.deduct]
22603 The specified template arguments must match the template
22604 parameters in kind (i.e., type, nontype, template), and there
22605 must not be more arguments than there are parameters;
22606 otherwise type deduction fails.
22608 Nontype arguments must match the types of the corresponding
22609 nontype template parameters, or must be convertible to the
22610 types of the corresponding nontype parameters as specified in
22611 _temp.arg.nontype_, otherwise type deduction fails.
22613 All references in the function type of the function template
22614 to the corresponding template parameters are replaced by the
22615 specified template argument values. If a substitution in a
22616 template parameter or in the function type of the function
22617 template results in an invalid type, type deduction fails. */
22628 explicit_targs);
22630 /* Adjust any explicit template arguments before entering the
22631 substitution context. */
22632 explicit_targs
22639 /* Substitute the explicit args into the function type. This is
22640 necessary so that, for instance, explicitly declared function
22641 arguments can match null pointed constants. If we were given
22642 an incomplete set of explicit args, we must not do semantic
22643 processing during substitution as we could create partial
22644 instantiations. */
22646 {
22651 /* Dig out the actual parm. */
22654 {
22657 }
22659 {
22662 }
22665 /* No explicit argument for this template parameter. */
22668 {
22669 /* Mark the argument pack as "incomplete". We could
22670 still deduce more arguments during unification.
22671 We remove this mark in type_unification_real. */
22676 /* We have some incomplete argument packs. */
22678 }
22679 }
22682 {
22684 {
22687 }
22690 /* Ignore any access checks; we'll see them again in
22691 instantiate_template and they might have the wrong
22692 access path at this point. */
22703 }
22705 /* Place the explicitly specified arguments in TARGS. */
22711 SET_NON_DEFAULT_TEMPLATE_ARGS_COUNT
22713 }
22716 {
22722 }
22727 /* Never do unification on the 'this' parameter. */
22731 {
22732 /* We're deducing for a call to the result of a template conversion
22733 function. The parms we really want are in return_type. */
22737 }
22739 {
22741 }
22743 /* We allow incomplete unification without an error message here
22744 because the standard doesn't seem to explicitly prohibit it. Our
22745 callers must be ready to deal with unification failures in any
22746 event. */
22748 /* If we aren't explaining yet, push tinst context so we can see where
22749 any errors (e.g. from class instantiations triggered by instantiation
22750 of default template arguments) come from. If we are explaining, this
22751 context is redundant. */
22753 {
22756 }
22766 /* Now that we have bindings for all of the template arguments,
22767 ensure that the arguments deduced for the template template
22768 parameters have compatible template parameter lists. We cannot
22769 check this property before we have deduced all template
22770 arguments, because the template parameter types of a template
22771 template parameter might depend on prior template parameters
22772 deduced after the template template parameter. The following
22773 ill-formed example illustrates this issue:
22775 template<typename T, template<T> class C> void f(C<5>, T);
22777 template<int N> struct X {};
22779 void g() {
22780 f(X<5>(), 5l); // error: template argument deduction fails
22781 }
22783 The template parameter list of 'C' depends on the template type
22784 parameter 'T', but 'C' is deduced to 'X' before 'T' is deduced to
22785 'long'. Thus, we can't check that 'C' cannot bind to 'X' at the
22786 time that we deduce 'C'. */
22789 {
22792 }
22794 deduced:
22796 /* As a refinement of CWG2369, check first and foremost non-dependent
22797 conversions that we know are not going to induce template instantiation
22798 (PR99599). */
22800 && incomplete
22806 /* CWG2369: Check satisfaction before non-deducible conversions. */
22808 {
22812 }
22814 /* DR 1391: All parameters have args, now check non-dependent parms for
22815 convertibility. We don't do this if all args were explicitly specified,
22816 as the standard says that we substitute explicit args immediately. */
22823 /* All is well so far. Now, check:
22825 [temp.deduct]
22827 When all template arguments have been deduced, all uses of
22828 template parameters in nondeduced contexts are replaced with
22829 the corresponding deduced argument values. If the
22830 substitution results in an invalid type, as described above,
22831 type deduction fails. */
22833 {
22836 }
22838 /* Also collect access checks from the instantiation. */
22851 /* Now perform any access checks encountered during substitution. */
22858 /* If we're looking for an exact match, check that what we got
22859 is indeed an exact match. It might not be if some template
22860 parameters are used in non-deduced contexts. But don't check
22861 for an exact match if we have dependent template arguments;
22862 in that case we're doing partial ordering, and we already know
22863 that we have two candidates that will provide the actual type. */
22865 {
22869 tree sarg
22875 {
22879 }
22881 /* add_candidates uses DEDUCE_EXACT for x.operator foo(), but args
22882 doesn't contain the trailing void, and conv fns are always (). */
22884 {
22888 }
22889 }
22891 /* After doing deduction with the inherited constructor, actually return an
22892 instantiation of the inheriting constructor. */
22898 fail:
22901 {
22903 /* Reset once we're all the way out. */
22905 }
22908 }
22910 /* Returns true iff PARM is a forwarding reference in the context of
22911 template argument deduction for TMPL. */
22913 static bool
22915 {
22916 /* [temp.deduct.call], "A forwarding reference is an rvalue reference to a
22917 cv-unqualified template parameter ..." */
22922 {
22924 /* [temp.deduct.call], "... that does not represent a template parameter
22925 of a class template (during class template argument deduction)." */
22929 {
22930 /* Since the template parameters of a synthesized guide consist of
22931 the template parameters of the class template followed by those of
22932 the constructor (if any), we can tell if PARM represents a template
22933 parameter of the class template by comparing its index with the
22934 arity of the class template. */
22939 }
22941 }
22943 }
22945 /* Adjust types before performing type deduction, as described in
22946 [temp.deduct.call] and [temp.deduct.conv]. The rules in these two
22947 sections are symmetric. PARM is the type of a function parameter
22948 or the return type of the conversion function. ARG is the type of
22949 the argument passed to the call, or the type of the value
22950 initialized with the result of the conversion function.
22951 ARG_EXPR is the original argument expression, which may be null. */
22953 static int
22955 unification_kind_t strict,
22958 tree arg_expr)
22959 {
22963 {
22968 /* [temp.deduct.conv] First remove a reference type on parm.
22969 DRs 322 & 976 affected this. */
22973 /* Swap PARM and ARG throughout the remainder of this
22974 function; the handling is precisely symmetric since PARM
22975 will initialize ARG rather than vice versa. */
22981 /* Core issue #873: Do the DR606 thing (see below) for these cases,
22982 too, but here handle it by stripping the reference from PARM
22983 rather than by adding it to ARG. */
22988 /* Nothing else to do in this case. */
22993 }
22996 {
22997 /* [temp.deduct.call]
22999 If P is not a reference type:
23001 --If A is an array type, the pointer type produced by the
23002 array-to-pointer standard conversion (_conv.array_) is
23003 used in place of A for type deduction; otherwise,
23005 --If A is a function type, the pointer type produced by
23006 the function-to-pointer standard conversion
23007 (_conv.func_) is used in place of A for type deduction;
23008 otherwise,
23010 --If A is a cv-qualified type, the top level
23011 cv-qualifiers of A's type are ignored for type
23012 deduction. */
23017 else
23019 }
23021 /* [temp.deduct.call], "If P is a forwarding reference and the argument is
23022 an lvalue, the type 'lvalue reference to A' is used in place of A for
23023 type deduction." */
23026 /* try_one_overload doesn't provide an arg_expr, but
23027 functions are always lvalues. */
23031 /* [temp.deduct.call]
23033 If P is a cv-qualified type, the top level cv-qualifiers
23034 of P's type are ignored for type deduction. If P is a
23035 reference type, the type referred to by P is used for
23036 type deduction. */
23039 {
23042 }
23045 }
23047 /* Return true if computing a conversion from FROM to TO might induce template
23048 instantiation. Conversely, if this predicate returns false then computing
23049 the conversion definitely won't induce template instantiation. */
23051 static bool
23053 {
23060 {
23064 }
23066 /* If one of the types is a not-yet-instantiated class template
23067 specialization, then computing the conversion might instantiate
23068 it in order to inspect bases, conversion functions and/or
23069 converting constructors. */
23078 /* Converting from one pointer type to another, or between
23079 reference-related types, always yields a standard conversion. */
23083 /* Converting to a non-aggregate class type will consider its
23084 user-declared constructors, which might induce instantiation. */
23089 /* Similarly, converting from a class type will consider its conversion
23090 functions. */
23095 /* Otherwise, computing this conversion definitely won't induce
23096 template instantiation. */
23098 }
23100 /* Subroutine of fn_type_unification. PARM is a function parameter of a
23101 template which doesn't contain any deducible template parameters; check if
23102 ARG is a suitable match for it. STRICT, FLAGS and EXPLAIN_P are as in
23103 unify_one_argument. */
23105 static int
23109 {
23110 tree type;
23114 else
23122 {
23125 }
23127 {
23129 {
23130 /* This conversion was already computed earlier (when
23131 computing only non-instantiating conversions). */
23134 }
23143 /* Avoid recalculating this in add_function_candidate. */
23144 ok = (*conv_p
23146 else
23150 }
23154 else
23156 }
23160 /* Returns true iff the expression EXPR is one from which a template
23161 argument can be deduced. In other words, if it's an undecorated
23162 use of a template non-type parameter. */
23164 static bool
23166 {
23167 /* Strip implicit conversions and implicit INDIRECT_REFs. */
23174 }
23176 /* Returns true iff the array domain DOMAIN uses a template parameter in a
23177 deducible way; that is, if it has a max value of <PARM> - 1. */
23179 static bool
23181 {
23190 }
23192 /* Returns true iff the template arguments ARGS use a template parameter
23193 in a deducible way. */
23195 static bool
23197 {
23199 {
23203 else
23204 {
23211 else
23213 }
23216 }
23218 }
23220 /* Returns true iff TYPE contains any deducible references to template
23221 parameters, as per 14.8.2.5. */
23223 static bool
23225 {
23229 /* T
23230 cv-list T
23231 TT<T>
23232 TT<i>
23233 TT<> */
23238 /* T*
23239 T&
23240 T&& */
23244 /* T[integer-constant ]
23245 type [i] */
23250 /* T type ::*
23251 type T::*
23252 T T::*
23253 T (type ::*)()
23254 type (T::*)()
23255 type (type ::*)(T)
23256 type (T::*)(T)
23257 T (type ::*)(T)
23258 T (T::*)()
23259 T (T::*)(T) */
23262 || (uses_deducible_template_parms
23265 /* template-name <T> (where template-name refers to a class template)
23266 template-name <i> (where template-name refers to a class template) */
23273 /* type (T)
23274 T()
23275 T(T) */
23277 {
23291 }
23294 }
23296 /* Subroutine of type_unification_real and unify_pack_expansion to
23297 handle unification of a single P/A pair. Parameters are as
23298 for those functions. */
23300 static int
23304 {
23311 /* We can't deduce anything from this, but we might get all the
23312 template args from other function args. */
23315 /* Implicit conversions (Clause 4) will be performed on a function
23316 argument to convert it to the type of the corresponding function
23317 parameter if the parameter type contains no template-parameters that
23318 participate in template argument deduction. */
23321 /* For function parameters with no deducible template parameters,
23322 just return. We'll check non-dependent conversions later. */
23326 {
23328 arg_strict = (UNIFY_ALLOW_OUTER_LEVEL
23329 | UNIFY_ALLOW_MORE_CV_QUAL
23343 }
23345 /* We only do these transformations if this is the top-level
23346 parameter_type_list in a call or declaration matching; in other
23347 situations (nested function declarators, template argument lists) we
23348 won't be comparing a type to an expression, and we don't do any type
23349 adjustments. */
23351 {
23353 {
23356 {
23357 /* [temp.deduct.type] A template-argument can be
23358 deduced from a pointer to function or pointer
23359 to member function argument if the set of
23360 overloaded functions does not contain function
23361 templates and at most one of a set of
23362 overloaded functions provides a unique
23363 match. */
23367 /* If a unique match was not found, this is a
23368 non-deduced context, so we still succeed. */
23370 }
23376 }
23380 }
23381 else
23386 /* For deduction from an init-list we need the actual list. */
23390 }
23392 /* for_each_template_parm callback that always returns 0. */
23394 static int
23396 {
23398 }
23400 /* for_each_template_parm any_fn callback to handle deduction of a template
23401 type argument from the type of an array bound. */
23403 static int
23405 {
23413 {
23419 }
23421 /* Keep walking. */
23423 }
23425 /* Try to deduce any not-yet-deduced template type arguments from the type of
23426 an array bound. This is handled separately from unify because 14.8.2.5 says
23427 "The type of a type parameter is only deduced from an array bound if it is
23428 not otherwise deduced." */
23430 static void
23432 {
23437 }
23439 /* Most parms like fn_type_unification.
23441 If SUBR is 1, we're being called recursively (to unify the
23442 arguments of a function or method parameter of a function
23443 template).
23445 CHECKS is a pointer to a vector of access checks encountered while
23446 substituting default template arguments. */
23448 static int
23450 tree full_targs,
23451 tree xparms,
23455 unification_kind_t strict,
23458 {
23463 tree parms;
23474 /* Reset the number of non-defaulted template arguments contained
23475 in TARGS. */
23478 again:
23483 /* Only fn_type_unification cares about terminal void. */
23490 {
23495 /* For a function parameter pack that occurs at the end of the
23496 parameter-declaration-list, the type A of each remaining
23497 argument of the call is compared with the type P of the
23498 declarator-id of the function parameter pack. */
23504 /* For a function parameter pack that does not occur at the
23505 end of the parameter-declaration-list, the type of the
23506 parameter pack is a non-deduced context. */
23509 /* [temp.deduct.conv] only applies to the deduction of the return
23510 type, which is always the first argument here. Other arguments
23511 (notably, explicit object parameters) should undergo normal
23512 call-like unification. */
23521 explain_p))
23523 }
23528 {
23531 /* Unify the remaining arguments with the pack expansion type. */
23532 tree argvec;
23535 /* Allocate a TREE_VEC and copy in all of the arguments */
23540 /* Copy the parameter into parmvec. */
23546 /* Advance to the end of the list of parameters. */
23548 }
23550 /* Fail if we've reached the end of the parm list, and more args
23551 are present, and the parm list isn't variadic. */
23554 /* Fail if parms are left and they don't have default values and
23555 they aren't all deduced as empty packs (c++/57397). This is
23556 consistent with sufficient_parms_p. */
23559 {
23563 do
23564 {
23567 count++;
23569 }
23573 type_pack_p);
23574 }
23577 {
23578 tsubst_flags_t complain = (explain_p
23579 ? tf_warning_or_error
23584 {
23588 /* Clear the "incomplete" flags on all argument packs now so that
23589 substituting them into later default arguments works. */
23591 {
23594 }
23602 {
23607 }
23609 /* If this is an undeduced nontype parameter that depends on
23610 a type parameter, try another pass; its type may have been
23611 deduced from a later argument than the one from which
23612 this parameter can be deduced. */
23617 {
23620 }
23622 /* Core issue #226 (C++0x) [temp.deduct]:
23624 If a template argument has not been deduced, its
23625 default template argument, if any, is used.
23627 When we are in C++98 mode, TREE_PURPOSE will either
23628 be NULL_TREE or ERROR_MARK_NODE, so we do not need
23629 to explicitly check cxx_dialect here. */
23631 /* OK, there is a default argument. Wait until after the
23632 conversion check to do substitution. */
23635 /* If the type parameter is a parameter pack, then it will
23636 be deduced to an empty parameter pack. */
23638 {
23639 tree arg;
23642 {
23645 }
23646 else
23653 }
23656 }
23658 /* During partial ordering, we deduce dependent template args. */
23661 /* Now substitute into the default template arguments. */
23663 {
23668 {
23672 }
23687 {
23688 /* The type of this non-type parameter depends on undeduced
23689 parameters. Don't try to use its default argument yet,
23690 since we might deduce an argument for it on the next pass,
23691 but do check whether the arguments we already have cause
23692 substitution failure, so that that happens before we try
23693 later default arguments (78489). */
23696 NULL_TREE);
23700 else
23702 }
23703 else
23704 {
23705 /* Even if the call is happening in template context, getting
23706 here means it's non-dependent, and a default argument is
23707 considered a separate definition under [temp.decls], so we can
23708 do this substitution without processing_template_decl. This
23709 is important if the default argument contains something that
23710 might be instantiation-dependent like access (87480). */
23715 {
23719 {
23725 }
23726 }
23729 {
23730 /* All template parameters within this default argument are
23731 deduced, so we can use it. */
23733 NULL_TREE);
23736 }
23741 }
23750 {
23752 /* The position of the first default template argument,
23753 is also the number of non-defaulted arguments in TARGS.
23754 Record that. */
23757 }
23758 }
23762 }
23768 }
23770 /* Subroutine of type_unification_real. Args are like the variables
23771 at the call site. ARG is an overloaded function (or template-id);
23772 we try deducing template args from each of the overloads, and if
23773 only one succeeds, we go with that. Modifies TARGS and returns
23774 true on success. */
23776 static bool
23778 tree targs,
23779 tree parm,
23780 tree arg,
23781 unification_kind_t strict,
23784 {
23791 {
23794 }
23795 else
23799 /* Handle `&x' where `x' is some static or non-static member
23800 function name. */
23806 /* Strip baselink information. */
23811 {
23812 /* If we got some explicit template args, we need to plug them into
23813 the affected templates before we try to unify, in case the
23814 explicit args will completely resolve the templates in question. */
23821 {
23832 {
23837 {
23838 /* Instantiate the function to deduce its return type. */
23842 }
23851 {
23854 }
23855 }
23858 }
23859 /* If no templates (or more than one) are fully resolved by the
23860 explicit arguments, this template-id is a non-deduced context; it
23861 could still be OK if we deduce all template arguments for the
23862 enclosing call through other arguments. */
23865 }
23867 /* If ARG is, for example, "(0, &f)" then its type will be unknown
23868 -- but the deduction does not succeed because the expression is
23869 not just the function on its own. */
23871 else
23873 {
23883 {
23886 }
23887 }
23889 /* [temp.deduct.type] A template-argument can be deduced from a pointer
23890 to function or pointer to member function argument if the set of
23891 overloaded functions does not contain function templates and at most
23892 one of a set of overloaded functions provides a unique match.
23894 CWG2918 allows multiple functions to match if they all have the same type,
23895 so that we can choose the most constrained later.
23897 So if we found multiple possibilities, we return success but don't
23898 deduce anything. */
23901 {
23905 {
23910 /* Don't forget explicit template arguments in a pack. */
23914 }
23915 }
23920 }
23922 /* Core DR 115: In contexts where deduction is done and fails, or in
23923 contexts where deduction is not done, if a template argument list is
23924 specified and it, along with any default template arguments, identifies
23925 a single function template specialization, then the template-id is an
23926 lvalue for the function template specialization. */
23928 tree
23930 {
23943 {
23946 }
23948 {
23951 }
23953 {
23956 }
23959 {
23963 /* If we got some explicit template args, we need to plug them into
23964 the affected templates before we try to unify, in case the
23965 explicit args will completely resolve the templates in question. */
23973 {
23984 {
23987 {
23990 }
23993 {
23996 }
23997 }
23998 }
24000 {
24008 {
24009 tree base
24012 }
24016 }
24018 /* There were no good options and at least one bad one, so let the
24019 user know what the problem is. */
24021 }
24023 }
24025 /* As above, but error out if the expression remains overloaded. */
24027 tree
24029 {
24032 {
24036 }
24038 }
24040 /* Subroutine of resolve_overloaded_unification; does deduction for a single
24041 overload. Fills TARGS with any deduced arguments, or error_mark_node if
24042 different overloads deduce different arguments for a given parm.
24043 ADDR_P is true if the expression for which deduction is being
24044 performed was of the form "& fn" rather than simply "fn".
24046 Returns 1 on success. */
24048 static int
24050 tree orig_targs,
24051 tree targs,
24052 tree parm,
24053 tree arg,
24054 unification_kind_t strict,
24058 {
24060 tree tempargs;
24066 /* [temp.deduct.type] A template-argument can be deduced from a pointer
24067 to function or pointer to member function argument if the set of
24068 overloaded functions does not contain function templates and at most
24069 one of a set of overloaded functions provides a unique match.
24071 So if this is a template, just return success. */
24084 /* We don't copy orig_targs for this because if we have already deduced
24085 some template args from previous args, unify would complain when we
24086 try to deduce a template parameter for the same argument, even though
24087 there isn't really a conflict. */
24094 /* First make sure we didn't deduce anything that conflicts with
24095 explicitly specified args. */
24097 {
24104 /* Since we're unifying against ourselves, we will fill in
24105 template args used in the function parm list with our own
24106 template parms. Discard them. */
24109 {
24110 /* Check that the argument at each index of the deduced argument pack
24111 is equivalent to the corresponding explicitly specified argument.
24112 We may have deduced more arguments than were explicitly specified,
24113 and that's OK. */
24115 /* We used to assert ARGUMENT_PACK_INCOMPLETE_P (oldelt) here, but
24116 that's wrong if we deduce the same argument pack from multiple
24117 function arguments: it's only incomplete the first time. */
24130 }
24133 }
24136 {
24141 }
24144 }
24146 /* PARM is a template class (perhaps with unbound template
24147 parameters). ARG is a fully instantiated type. If ARG can be
24148 bound to PARM, return ARG, otherwise return NULL_TREE. TPARMS and
24149 TARGS are as for unify. */
24151 static tree
24154 {
24162 /* We need to make a new template argument vector for the call to
24163 unify. If we used TARGS, we'd clutter it up with the result of
24164 the attempted unification, even if this class didn't work out.
24165 We also don't want to commit ourselves to all the unifications
24166 we've already done, since unification is supposed to be done on
24167 an argument-by-argument basis. In other words, consider the
24168 following pathological case:
24170 template <int I, int J, int K>
24171 struct S {};
24173 template <int I, int J>
24174 struct S<I, J, 2> : public S<I, I, I>, S<J, J, J> {};
24176 template <int I, int J, int K>
24177 void f(S<I, J, K>, S<I, I, I>);
24179 void g() {
24180 S<0, 0, 0> s0;
24181 S<0, 1, 2> s2;
24183 f(s0, s2);
24184 }
24186 Now, by the time we consider the unification involving `s2', we
24187 already know that we must have `f<0, 0, 0>'. But, even though
24188 `S<0, 1, 2>' is derived from `S<0, 0, 0>', the code is invalid
24189 because there are two ways to unify base classes of S<0, 1, 2>
24190 with S<I, I, I>. If we kept the already deduced knowledge, we
24191 would reject the possibility I=1. */
24199 else
24206 }
24208 /* Given a template type PARM and a class type ARG, find the unique
24209 base type in ARG that is an instance of PARM. We do not examine
24210 ARG itself; only its base-classes. If there is not exactly one
24211 appropriate base class, return NULL_TREE. PARM may be the type of
24212 a partial specialization, as well as a plain template type. Used
24213 by unify. */
24215 static enum template_base_result
24218 {
24220 tree binfo;
24226 {
24227 /* The type could not be completed. */
24230 }
24232 /* Walk in inheritance graph order. The search order is not
24233 important, and this avoids multiple walks of virtual bases. */
24235 {
24240 {
24241 /* If there is more than one satisfactory baseclass, then:
24243 [temp.deduct.call]
24245 If they yield more than one possible deduced A, the type
24246 deduction fails.
24248 applies. */
24250 {
24251 /* [temp.deduct.call]/4.3: If there is a class C that is a
24252 (direct or indirect) base class of D and derived (directly or
24253 indirectly) from a class B and that would be a valid deduced
24254 A, the deduced A cannot be B or pointer to B, respectively. */
24256 /* Ignore r. */
24260 else
24261 {
24264 }
24265 }
24268 }
24269 }
24273 }
24275 /* Returns the level of DECL, which declares a template parameter. */
24277 static int
24279 {
24281 {
24291 }
24293 }
24295 /* Decide whether ARG can be unified with PARM, considering only the
24296 cv-qualifiers of each type, given STRICT as documented for unify.
24297 Returns nonzero iff the unification is OK on that basis. */
24299 static int
24301 {
24307 {
24308 /* Although a CVR qualifier is ignored when being applied to a
24309 substituted template parameter ([8.3.2]/1 for example), that
24310 does not allow us to unify "const T" with "int&" because both
24311 types are not of the form "cv-list T" [14.8.2.5 temp.deduct.type].
24312 It is ok when we're allowing additional CV qualifiers
24313 at the outer level [14.8.2.1]/3,1st bullet. */
24322 }
24333 }
24335 /* Determines the LEVEL and INDEX for the template parameter PARM. */
24336 void
24338 {
24342 {
24345 }
24346 else
24347 {
24350 }
24351 }
24353 #define RECUR_AND_CHECK_FAILURE(TP, TA, P, A, S, EP) \
24354 do { \
24355 if (unify (TP, TA, P, A, S, EP)) \
24356 return 1; \
24357 } while (0)
24359 /* Unifies the remaining arguments in PACKED_ARGS with the pack
24360 expansion at the end of PACKED_PARMS. Returns 0 if the type
24361 deduction succeeds, 1 otherwise. STRICT is the same as in
24362 fn_type_unification. CALL_ARGS_P is true iff PACKED_ARGS is actually a
24363 function call argument list. We'll need to adjust the arguments to make them
24364 types. SUBR tells us if this is from a recursive call to
24365 type_unification_real, or for comparing two template argument
24366 lists. */
24368 static int
24372 {
24373 tree parm
24379 /* Add in any args remembered from an earlier partial instantiation. */
24387 /* Determine the parameter packs we will be deducing from the
24388 pattern, and record their current deductions. */
24391 {
24395 /* Only template parameter packs can be deduced, not e.g. function
24396 parameter packs or __bases or __integer_pack. */
24400 /* Determine the index and level of this parameter pack. */
24405 /* Keep track of the parameter packs and their corresponding
24406 argument packs. */
24409 }
24411 /* Loop through all of the arguments that have not yet been
24412 unified and unify each with the pattern. */
24414 {
24415 tree parm;
24419 /* For each parameter pack, set its TMPL_ARG to either NULL_TREE
24420 or the element of its argument pack at the current index if
24421 this argument was explicitly specified. */
24423 {
24432 {
24435 }
24437 }
24439 /* If we had explicit template arguments, substitute them into the
24440 pattern before deduction. */
24442 {
24443 /* Some arguments might still be unspecified or dependent. */
24451 NULL_TREE);
24456 }
24457 else
24460 /* Unify the pattern with the current argument. */
24462 explain_p))
24465 /* For each parameter pack, collect the deduced value. */
24467 {
24473 }
24474 }
24476 /* Verify that the results of unification with the parameter packs
24477 produce results consistent with what we've seen before, and make
24478 the deduced argument packs available. */
24480 {
24487 /* By default keep the original deduced argument pack.
24488 If necessary, more specific code is going to update the
24489 resulting deduced argument later down in this function. */
24493 /* If NEW_ARGS contains any NULL_TREE entries, we didn't
24494 actually deduce anything. */
24502 {
24503 /* If we had fewer function args than explicit template args,
24504 just use the explicits. */
24509 }
24512 {
24513 tree result;
24514 /* Build the deduced *_ARGUMENT_PACK. */
24516 {
24519 }
24520 else
24525 /* Note the deduced argument packs for this parameter
24526 pack. */
24528 }
24532 {
24533 /* We only had the explicitly-provided arguments before, but
24534 now we have a complete set of arguments. */
24540 }
24541 else
24542 {
24546 /* During template argument deduction for the aggregate deduction
24547 candidate, the number of elements in a trailing parameter pack
24548 is only deduced from the number of remaining function
24549 arguments if it is not otherwise deduced. */
24552 /* FIXME This isn't set properly for partial instantiations. */
24558 /* Inconsistent unification of this parameter pack. */
24560 bad_old_arg,
24561 bad_new_arg);
24562 }
24563 }
24566 }
24568 /* Handle unification of the domain of an array. PARM_DOM and ARG_DOM are
24569 INTEGER_TYPEs representing the TYPE_DOMAIN of ARRAY_TYPEs. The other
24570 parameters and return value are as for unify. */
24572 static int
24576 {
24577 tree parm_max;
24578 tree arg_max;
24582 /* Our representation of array types uses "N - 1" as the
24583 TYPE_MAX_VALUE for an array with "N" elements, if "N" is
24584 not an integer constant. We cannot unify arbitrarily
24585 complex expressions, so we eliminate the MINUS_EXPRs
24586 here. */
24590 {
24593 }
24597 {
24598 /* The ARG_MAX may not be a simple MINUS_EXPR, if we are
24599 trying to unify the type of a variable with the type
24600 of a template parameter. For example:
24602 template <unsigned int N>
24603 void f (char (&) [N]);
24604 int g();
24605 void h(int i) {
24606 char a[g(i)];
24607 f(a);
24608 }
24610 Here, the type of the ARG will be "int [g(i)]", and
24611 may be a SAVE_EXPR, etc. */
24615 }
24617 /* If only one of the bounds used a MINUS_EXPR, compensate
24618 by adding one to the other bound. */
24621 integer_type_node,
24622 parm_max,
24623 integer_one_node);
24626 integer_type_node,
24627 arg_max,
24628 integer_one_node);
24632 }
24634 /* Returns whether T, a P or A in unify, is a type, template or expression. */
24638 static pa_kind_t
24640 {
24649 else
24651 }
24653 /* Deduce the value of template parameters. TPARMS is the (innermost)
24654 set of template parameters to a template. TARGS is the bindings
24655 for those template parameters, as determined thus far; TARGS may
24656 include template arguments for outer levels of template parameters
24657 as well. PARM is a parameter to a template function, or a
24658 subcomponent of that parameter; ARG is the corresponding argument.
24659 This function attempts to match PARM with ARG in a manner
24660 consistent with the existing assignments in TARGS. If more values
24661 are deduced, then TARGS is updated.
24663 Returns 0 if the type deduction succeeds, 1 otherwise. The
24664 parameter STRICT is a bitwise or of the following flags:
24666 UNIFY_ALLOW_NONE:
24667 Require an exact match between PARM and ARG.
24668 UNIFY_ALLOW_MORE_CV_QUAL:
24669 Allow the deduced ARG to be more cv-qualified (by qualification
24670 conversion) than ARG.
24671 UNIFY_ALLOW_LESS_CV_QUAL:
24672 Allow the deduced ARG to be less cv-qualified than ARG.
24673 UNIFY_ALLOW_DERIVED:
24674 Allow the deduced ARG to be a template base class of ARG,
24675 or a pointer to a template base class of the type pointed to by
24676 ARG.
24677 UNIFY_ALLOW_INTEGER:
24678 Allow any integral type to be deduced. See the TEMPLATE_PARM_INDEX
24679 case for more information.
24680 UNIFY_ALLOW_OUTER_LEVEL:
24681 This is the outermost level of a deduction. Used to determine validity
24682 of qualification conversions. A valid qualification conversion must
24683 have const qualified pointers leading up to the inner type which
24684 requires additional CV quals, except at the outer level, where const
24685 is not required [conv.qual]. It would be normal to set this flag in
24686 addition to setting UNIFY_ALLOW_MORE_CV_QUAL.
24687 UNIFY_ALLOW_OUTER_MORE_CV_QUAL:
24688 This is the outermost level of a deduction, and PARM can be more CV
24689 qualified at this point.
24690 UNIFY_ALLOW_OUTER_LESS_CV_QUAL:
24691 This is the outermost level of a deduction, and PARM can be less CV
24692 qualified at this point. */
24694 static int
24697 {
24699 tree targ;
24700 tree tparm;
24702 tsubst_flags_t complain = (explain_p
24703 ? tf_warning_or_error
24706 /* I don't think this will do the right thing with respect to types.
24707 But the only case I've seen it in so far has been array bounds, where
24708 signedness is the only information lost, and I think that will be
24709 okay. VIEW_CONVERT_EXPR can appear with class NTTP, thanks to
24710 finish_id_expression_1, and are also OK. */
24719 /* We can't deduce anything from this, but we might get all the
24720 template args from other function args. */
24726 /* Stripping IMPLICIT_CONV_EXPR above can produce this mismatch
24727 (g++.dg/abi/mangle57.C). */
24732 /* If PARM uses template parameters, then we can't bail out here,
24733 even if ARG == PARM, since we won't record unifications for the
24734 template parameters. We might need them if we're trying to
24735 figure out which of two things is more specialized. */
24740 /* Handle init lists early, so the rest of the function can assume
24741 we're dealing with a type. */
24743 {
24744 tree elttype;
24749 /* We can only deduce from an initializer list argument if the
24750 parameter is std::initializer_list or an array; otherwise this
24751 is a non-deduced context. */
24756 else
24757 {
24759 /* Deduction is defined in terms of a single type, so just punt
24760 on the (bizarre) std::initializer_list<T...>. */
24763 }
24768 /* If ELTTYPE has no deducible template parms, skip deduction from
24770 else
24772 {
24780 {
24784 /* It should only be possible to get here for a call. */
24786 elt_strict |= maybe_adjust_types_for_deduction
24789 }
24792 explain_p);
24793 }
24797 {
24798 /* Also deduce from the length of the initializer list. */
24805 }
24807 /* If the std::initializer_list<T> deduction worked, replace the
24808 deduced A with std::initializer_list<A>. */
24810 {
24815 }
24817 }
24819 /* If parm and arg aren't the same kind of thing (template, type, or
24820 expression), fail early. */
24824 /* Immediately reject some pairs that won't unify because of
24825 cv-qualification mismatches. */
24828 /* It is the elements of the array which hold the cv quals of an array
24829 type, and the elements might be template type parms. We'll check
24830 when we recurse. */
24832 /* We check the cv-qualifiers when unifying with template type
24833 parameters below. We want to allow ARG `const T' to unify with
24834 PARM `T' for example, when computing which of two templates
24835 is more specialized, for example. */
24844 /* PMFs recurse at the same level, so don't strip this yet. */
24852 {
24856 /* In a type which contains a nested-name-specifier, template
24857 argument values cannot be deduced for template parameters used
24858 within the nested-name-specifier. */
24870 /* The PARM is not one we're trying to unify. Just check
24871 to see if it matches ARG. */
24872 {
24877 else
24879 }
24886 /* Check for mixed types and values. */
24894 {
24897 {
24898 /* First try to match ARG directly. */
24900 explain_p);
24902 {
24903 /* Otherwise, look for a suitable base of ARG, as below. */
24910 }
24911 }
24912 /* ARG must be constructed from a template class or a template
24913 template parameter. */
24918 /* Deduce arguments T, i from TT<T> or TT<i>. */
24924 /* If the template is a template template parameter, use the
24925 TEMPLATE_TEMPLATE_PARM for matching. */
24928 /* Fall through to deduce template name. */
24929 }
24933 {
24934 /* Deduce template name TT from TT, TT<>, TT<T> and TT<i>. */
24936 /* Simple cases: Value already set, does match or doesn't. */
24941 }
24942 else
24943 {
24944 /* If PARM is `const T' and ARG is only `int', we don't have
24945 a match unless we are allowing additional qualification.
24946 If ARG is `const int' and PARM is just `T' that's OK;
24947 that binds `const int' to `T'. */
24952 /* Consider the case where ARG is `const volatile int' and
24953 PARM is `const T'. Then, T should be `volatile int'. */
24954 arg = cp_build_qualified_type
24959 /* Simple cases: Value already set, does match or doesn't. */
24965 /* Make sure that ARG is not a variable-sized array. (Note
24966 that were talking about variable-sized arrays (like
24967 `int[n]'), rather than arrays of unknown size (like
24968 `int[]').) We'll get very confused by such a type since
24969 the bound of the array is not constant, and therefore
24970 not mangleable. Besides, such types are not allowed in
24971 ISO C++, so we can do as we please here. We do allow
24972 them for 'auto' deduction, since that isn't ABI-exposed. */
24976 /* Strip typedefs as in convert_template_argument. */
24978 }
24980 /* If ARG is a parameter pack or an expansion, we cannot unify
24981 against it unless PARM is also a parameter pack. */
24986 /* If the argument deduction results is a METHOD_TYPE,
24987 then there is a problem.
24988 METHOD_TYPE doesn't map to any real C++ type the result of
24989 the deduction cannot be of that type. */
25003 {
25004 /* The PARM is not one we're trying to unify. Just check
25005 to see if it matches ARG. */
25011 }
25017 {
25021 /* We're deducing from an array bound, the type doesn't matter.
25022 This conversion should match the one below. */
25028 }
25030 /* [temp.deduct.type] If, in the declaration of a function template
25031 with a non-type template-parameter, the non-type
25032 template-parameter is used in an expression in the function
25033 parameter-list and, if the corresponding template-argument is
25034 deduced, the template-argument type shall match the type of the
25035 template-parameter exactly, except that a template-argument
25036 deduced from an array bound may be of any integral type.
25037 The non-type parameter might use already deduced type parameters. */
25040 /* We don't have enough levels of args to do any substitution. This
25042 else
25043 {
25049 {
25052 LOOKUP_NORMAL,
25056 }
25057 }
25061 /* Template-parameter dependent expression. Just accept it for now.
25062 It will later be processed in convert_template_argument. */
25063 ;
25067 /* OK. Ignore top-level quals here because a class-type template
25071 /* Convert the ARG to the type of PARM; the deduced non-type
25072 template argument must exactly match the types of the
25073 corresponding parameter. This conversion should match the
25074 one above. */
25077 {
25078 /* We haven't deduced the type of this parameter yet. */
25080 /* We deduce from array bounds in try_array_deduction. */
25083 {
25084 /* Deduce it from the non-type argument. As above, ignore
25085 top-level quals here too. */
25090 /* Now check whether the type of this parameter is still
25091 dependent, and give up if so. */
25097 }
25098 else
25099 /* Try again later. */
25101 }
25102 else
25105 /* If ARG is a parameter pack or an expansion, we cannot unify
25106 against it unless PARM is also a parameter pack. */
25111 {
25114 }
25119 {
25120 /* A pointer-to-member constant can be unified only with
25121 another constant. */
25125 /* Just unify the class member. It would be useless (and possibly
25126 wrong, depending on the strict flags) to unify also
25127 PTRMEM_CST_CLASS, because we want to be sure that both parm and
25128 arg refer to the same variable, even if through different
25129 classes. For instance:
25131 struct A { int x; };
25132 struct B : A { };
25134 Unification of &A::x and &B::x must succeed. */
25137 }
25140 {
25144 /* [temp.deduct.call]
25146 A can be another pointer or pointer to member type that can
25147 be converted to the deduced A via a qualification
25148 conversion (_conv.qual_).
25150 We pass down STRICT here rather than UNIFY_ALLOW_NONE.
25151 This will allow for additional cv-qualification of the
25152 pointed-to types if appropriate. */
25155 /* The derived-to-base conversion only persists through one
25156 level of pointers. */
25161 }
25195 /* We have already checked cv-qualification at the top of the
25196 function. */
25200 /* As far as unification is concerned, this wins. Later checks
25201 will invalidate it if necessary. */
25204 /* Types INTEGER_CST and MINUS_EXPR can come from array bounds. */
25205 /* Type INTEGER_CST can come from ordinary constant template args. */
25221 {
25231 /* Check for pack expansions in the parameters. */
25233 {
25235 {
25237 /* We can unify against something with a trailing
25238 parameter pack. */
25240 else
25241 /* [temp.deduct.type]/9: If the template argument list of
25242 P contains a pack expansion that is not the last
25243 template argument, the entire template argument list
25244 is a non-deduced context. */
25246 }
25247 }
25249 /* If we don't have enough arguments to satisfy the parameters
25250 (not counting the pack expression at the end), or we have
25251 too many arguments for a parameter list that doesn't end in
25252 a pack expression, we can't unify. */
25258 /* Unify all of the parameters that precede the (optional)
25259 pack expression. */
25261 {
25266 }
25269 DEDUCE_EXACT,
25272 }
25280 {
25288 }
25293 {
25297 {
25298 /* First, we try to unify the PARM and ARG directly. */
25303 {
25304 /* Fallback to the special case allowed in
25305 [temp.deduct.call]:
25307 If P is a class, and P has the form
25308 template-id, then A can be a derived class of
25309 the deduced A. Likewise, if P is a pointer to
25310 a class of the form template-id, A can be a
25311 pointer to a derived class pointed to by the
25312 deduced A. */
25318 {
25319 /* Don't give the derived diagnostic if we're
25320 already dealing with the same template. */
25321 bool same_template
25327 }
25328 }
25329 }
25333 /* Perhaps PARM is something like S<U> and ARG is S<int>.
25334 Then, we should unify `int' and `U'. */
25336 else
25337 /* There's no chance of unification succeeding. */
25345 else
25347 }
25354 {
25357 tree a;
25363 /* CV qualifications for methods can never be deduced, they must
25364 match exactly. We need to check them explicitly here,
25365 because type_unification_real treats them as any other
25366 cv-qualified parameter. */
25368 && (!check_cv_quals_for_unify
25396 {
25406 else
25407 {
25410 /* Here "less cv-qual" means the deduced arg (i.e. parm) has
25411 /more/ noexcept, since function pointer conversions are the
25412 reverse of qualification conversions. */
25417 else
25419 }
25420 }
25422 {
25423 /* As for noexcept. */
25430 else
25432 }
25435 }
25438 /* Unify a pointer to member with a pointer to member function, which
25439 deduces the type of the member as a function type. */
25441 {
25442 /* Check top-level cv qualifiers */
25450 /* Determine the type of the function we are unifying against. */
25454 }
25465 /* CONST_DECL should already have been folded to its DECL_INITIAL. */
25471 /* Matched cases are handled by the ARG == PARM test above. */
25475 /* We might get a variable as a non-type template argument in parm if the
25476 corresponding parameter is type-dependent. Make any necessary
25477 adjustments based on whether arg is a reference. */
25481 {
25486 }
25487 /* Now use the normal expression code to check whether they match. */
25498 /* Cannot deduce anything from TYPEOF_TYPE, DECLTYPE_TYPE,
25499 or TRAIT_TYPE nodes. */
25503 /* Unification fails if we hit an error node. */
25508 {
25518 }
25519 /* FALLTHRU */
25522 /* An unresolved overload is a nondeduced context. */
25528 expr:
25529 /* We must be looking at an expression. This can happen with
25530 something like:
25532 template <int I>
25533 void foo(S<I>, S<I + 2>);
25535 or
25537 template<typename T>
25538 void foo(A<T, T{}>);
25540 This is a "non-deduced context":
25542 [deduct.type]
25544 The non-deduced contexts are:
25546 --A non-type template argument or an array bound in which
25547 a subexpression references a template parameter.
25549 In these cases, we assume deduction succeeded, but don't
25550 actually infer any unifications. */
25555 else
25557 }
25558 }
25559 #undef RECUR_AND_CHECK_FAILURE
25560 \f
25561 /* Note that DECL can be defined in this translation unit, if
25562 required. */
25564 static void
25566 {
25567 tree clone;
25571 }
25573 /* Called if RESULT is explicitly instantiated, or is a member of an
25574 explicitly instantiated class. */
25576 void
25578 {
25581 /* If this entity has already been written out, it's too late to
25582 make any modifications. */
25586 /* consteval functions are never emitted. */
25591 /* For anonymous namespace we don't need to do anything. */
25593 {
25596 }
25599 /* The TREE_PUBLIC flag for function declarations will have been
25600 set correctly by tsubst. */
25604 {
25607 }
25608 else
25609 {
25612 /* Always make artificials weak. */
25615 /* For WIN32 we also want to put explicit instantiations in
25616 linkonce sections. */
25621 /* If the function has already been instantiated, clear DECL_EXTERNAL,
25622 since start_preparsed_function wouldn't have if we had an earlier
25623 extern explicit instantiation. */
25625 }
25627 /* If EXTERN_P, then this function will not be emitted -- unless
25628 followed by an explicit instantiation, at which point its linkage
25629 will be adjusted. If !EXTERN_P, then this function will be
25630 emitted here. In neither circumstance do we want
25631 import_export_decl to adjust the linkage. */
25633 }
25635 /* Subroutine of more_specialized_fn: check whether TARGS is missing any
25636 important template arguments. If any are missing, we check whether
25637 they're important by using error_mark_node for substituting into any
25638 args that were used for partial ordering (the ones between ARGS and END)
25639 and seeing if it bubbles up. */
25641 static bool
25643 {
25647 {
25650 }
25652 {
25656 }
25658 }
25660 /* Given two function templates PAT1 and PAT2, return:
25662 1 if PAT1 is more specialized than PAT2 as described in [temp.func.order].
25663 -1 if PAT2 is more specialized than PAT1.
25664 0 if neither is more specialized.
25666 LEN indicates the number of parameters we should consider
25667 (defaulted parameters should not be considered).
25669 The 1998 std underspecified function template partial ordering, and
25670 DR214 addresses the issue. We take pairs of arguments, one from
25671 each of the templates, and deduce them against each other. One of
25672 the templates will be more specialized if all the *other*
25673 template's arguments deduce against its arguments and at least one
25674 of its arguments *does* *not* deduce against the other template's
25675 corresponding argument. Deduction is done as for class templates.
25676 The arguments used in deduction have reference and top level cv
25677 qualifiers removed. Iff both arguments were originally reference
25678 types *and* deduction succeeds in both directions, an lvalue reference
25679 wins against an rvalue reference and otherwise the template
25680 with the more cv-qualified argument wins for that pairing (if
25681 neither is more cv-qualified, they both are equal). Unlike regular
25682 deduction, after all the arguments have been deduced in this way,
25683 we do *not* verify the deduced template argument values can be
25684 substituted into non-deduced contexts.
25686 The logic can be a bit confusing here, because we look at deduce1 and
25687 targs1 to see if pat2 is at least as specialized, and vice versa; if we
25688 can find template arguments for pat1 to make arg1 look like arg2, that
25689 means that arg2 is at least as specialized as arg1. */
25691 int
25693 {
25706 /* C++17 [temp.func.order]/3 (CWG532)
25708 If only one of the function templates M is a non-static member of some
25709 class A, M is considered to have a new first parameter inserted in its
25710 function parameter list. Given cv as the cv-qualifiers of M (if any), the
25711 new parameter is of type "rvalue reference to cv A" if the optional
25712 ref-qualifier of M is && or if M has no ref-qualifier and the first
25713 parameter of the other template has rvalue reference type. Otherwise, the
25714 new parameter is of type "lvalue reference to cv A". */
25717 {
25718 /* Note C++20 DR2445 extended the above to static member functions, but
25719 I think the old G++ behavior of just skipping the object
25720 parameter when comparing to a static member function was better, so
25721 let's stick with that for now. This is CWG2834. --jason 2023-12 */
25723 {
25726 }
25729 }
25732 {
25733 /* Note DR2445 also (IMO wrongly) removed the "only one" above, which
25734 would break e.g. cpp1y/lambda-generic-variadic5.C. */
25735 len--;
25738 }
25741 {
25742 /* The other is a non-member or explicit object member function;
25743 rewrite the implicit object parameter to a reference. */
25752 {
25758 }
25761 }
25763 /* If only one is a conversion operator, they are unordered. */
25767 /* Consider the return type for a conversion function */
25769 {
25772 len++;
25773 }
25775 processing_template_decl++;
25781 /* Stop when an ellipsis is seen. */
25783 {
25794 {
25795 /* When both arguments are pack expansions, we need only
25796 unify the patterns themselves. */
25800 /* This is the last comparison we need to do. */
25802 }
25805 {
25809 }
25812 {
25816 }
25822 {
25828 /* Setup the parameter vector, which contains only ARG1. */
25831 /* Setup the argument vector, which contains the remaining
25832 arguments. */
25841 /* We cannot deduce in the other direction, because ARG1 is
25842 a pack expansion but ARG2 is not. */
25844 }
25846 {
25852 /* Setup the parameter vector, which contains only ARG1. */
25855 /* Setup the argument vector, which contains the remaining
25856 arguments. */
25865 /* We cannot deduce in the other direction, because ARG2 is
25866 a pack expansion but ARG1 is not.*/
25868 }
25870 else
25871 {
25872 /* The normal case, where neither argument is a pack
25873 expansion. */
25880 }
25882 /* If we couldn't deduce arguments for tparms1 to make arg1 match
25883 arg2, then arg2 is not as specialized as arg1. */
25889 /* "If, for a given type, deduction succeeds in both directions
25890 (i.e., the types are identical after the transformations above)
25891 and both P and A were reference types (before being replaced with
25892 the type referred to above):
25893 - if the type from the argument template was an lvalue reference and
25894 the type from the parameter template was not, the argument type is
25895 considered to be more specialized than the other; otherwise,
25896 - if the type from the argument template is more cv-qualified
25897 than the type from the parameter template (as described above),
25898 the argument type is considered to be more specialized than the other;
25899 otherwise,
25900 - neither type is more specialized than the other." */
25903 {
25905 {
25908 else
25910 }
25912 {
25917 }
25918 }
25921 /* We've failed to deduce something in either direction.
25922 These must be unordered. */
25927 /* We have already processed all of the arguments in our
25928 handing of the pack expansion type. */
25933 }
25935 /* "In most cases, all template parameters must have values in order for
25936 deduction to succeed, but for partial ordering purposes a template
25937 parameter may remain without a value provided it is not used in the
25938 types being used for partial ordering."
25940 Thus, if we are missing any of the targs1 we need to substitute into
25941 origs1, then pat2 is not as specialized as pat1. This can happen when
25942 there is a nondeduced context. */
25948 processing_template_decl--;
25950 /* If both deductions succeed, the partial ordering selects the more
25951 constrained template. */
25952 /* P2113: If the corresponding template-parameters of the
25953 template-parameter-lists are not equivalent ([temp.over.link]) or if
25954 the function parameters that positionally correspond between the two
25955 templates are not of the same type, neither template is more
25956 specialized than the other. */
25961 {
25967 }
25969 /* All things being equal, if the next argument is a pack expansion
25970 for one function but not for the other, prefer the
25971 non-variadic function. FIXME this is bogus; see c++/41958. */
25975 {
25978 }
25984 else
25986 }
25988 /* Determine which of two partial specializations of TMPL is more
25989 specialized.
25991 PAT1 is a TREE_LIST whose TREE_VALUE is the TEMPLATE_DECL corresponding
25992 to the first partial specialization. The TREE_PURPOSE is the
25993 innermost set of template parameters for the partial
25994 specialization. PAT2 is similar, but for the second template.
25996 Return 1 if the first partial specialization is more specialized;
25997 -1 if the second is more specialized; 0 if neither is more
25998 specialized.
26000 See [temp.class.order] for information about determining which of
26001 two templates is more specialized. */
26003 static int
26005 {
26006 tree targs;
26015 /* Just like what happens for functions, if we are ordering between
26016 different template specializations, we may encounter dependent
26017 types in the arguments, and we need our dependency check functions
26018 to behave correctly. */
26022 {
26025 }
26029 {
26032 }
26035 /* If both deductions succeed, the partial ordering selects the more
26036 constrained template. */
26040 /* In the case of a tie where at least one of the templates
26041 has a parameter pack at the end, the template with the most
26042 non-packed parameters wins. */
26044 && any_deductions
26047 {
26053 /* We don't count the pack expansion at the end. */
26063 }
26066 }
26068 /* Return the template arguments that will produce the function signature
26069 DECL from the function template FN, with the explicit template
26070 arguments EXPLICIT_ARGS. If CHECK_RETTYPE is true, the return type must
26071 also match. Return NULL_TREE if no satisfactory arguments could be
26072 found. */
26074 static tree
26076 {
26080 tree decl_arg_types;
26083 tree arg;
26087 /* Never do unification on the 'this' parameter. */
26109 }
26111 /* Return the innermost template arguments that, when applied to a partial
26112 specialization SPEC_TMPL of TMPL, yield the ARGS.
26114 For example, suppose we have:
26116 template <class T, class U> struct S {};
26117 template <class T> struct S<T*, int> {};
26119 Then, suppose we want to get `S<double*, int>'. SPEC_TMPL will be the
26120 partial specialization and the ARGS will be {double*, int}. The resulting
26121 vector will be {double}, indicating that `T' is bound to `double'. */
26123 static tree
26125 {
26127 tree spec_args
26130 tree deduced_args;
26131 tree innermost_deduced_args;
26135 {
26139 innermost_deduced_args);
26140 }
26141 else
26145 again:
26154 {
26156 {
26162 }
26164 }
26167 {
26170 }
26172 /* Verify that nondeduced template arguments agree with the type
26173 obtained from argument deduction.
26175 For example:
26177 struct A { typedef int X; };
26178 template <class T, class U> struct C {};
26179 template <class T> struct C<T, typename T::X> {};
26181 Then with the instantiation `C<A, int>', we can deduce that
26182 `T' is `A' but unify () does not check whether `typename T::X'
26183 is `int'. */
26194 /* We only need to check the innermost arguments; the other
26195 arguments will always agree. */
26200 /* Now that we have bindings for all of the template arguments,
26201 ensure that the arguments deduced for the template template
26202 parameters have compatible template parameter lists. See the use
26203 of template_template_parm_bindings_ok_p in fn_type_unification
26204 for more information. */
26209 }
26211 // Compare two function templates T1 and T2 by deducing bindings
26212 // from one against the other. If both deductions succeed, compare
26213 // constraints to see which is more constrained.
26214 static int
26216 {
26221 {
26224 }
26227 {
26230 }
26232 // If both deductions succeed, then one may be more constrained.
26237 }
26239 /* TEMPLATES is a TREE_LIST. Each TREE_VALUE is a TEMPLATE_DECL.
26240 Return the TREE_LIST node with the most specialized template, if
26241 any. If there is no most specialized template, the error_mark_node
26242 is returned.
26244 Note that this function does not look at, or modify, the
26245 TREE_PURPOSE or TREE_TYPE of any of the nodes. Since the node
26246 returned is one of the elements of INSTANTIATIONS, callers may
26247 store information in the TREE_PURPOSE or TREE_TYPE of the nodes,
26248 and retrieve it from the value returned. */
26250 tree
26252 {
26259 {
26265 {
26266 /* Equally specialized, move to next function. If there
26267 is no next function, nothing's most specialized. */
26272 }
26273 }
26276 /* Now verify that champ is better than everything earlier in the
26277 instantiation list. */
26280 {
26283 }
26284 }
26286 processing_template_decl--;
26292 }
26294 /* If DECL is a specialization of some template, return the most
26295 general such template. Otherwise, returns NULL_TREE.
26297 For example, given:
26299 template <class T> struct S { template <class U> void f(U); };
26301 if TMPL is `template <class U> void S<int>::f(U)' this will return
26302 the full template. This function will not trace past partial
26303 specializations, however. For example, given in addition:
26305 template <class T> struct S<T*> { template <class U> void f(U); };
26307 if TMPL is `template <class U> void S<int*>::f(U)' this will return
26308 `template <class T> template <class U> S<T*>::f(U)'. */
26310 tree
26312 {
26314 {
26317 /* The TI_TEMPLATE can be an IDENTIFIER_NODE for a
26318 template friend, or a FIELD_DECL for a capture pack. */
26321 }
26326 /* Look for more and more general templates. */
26328 {
26329 /* The DECL_TI_TEMPLATE can be an IDENTIFIER_NODE in some cases.
26330 (See cp-tree.h for details.) */
26339 /* Stop if we run into an explicitly specialized class template. */
26346 }
26349 }
26351 /* Return the most specialized of the template partial specializations
26352 which can produce TARGET, a specialization of some class or variable
26353 template. The value returned is a TEMPLATE_INFO; the TI_TEMPLATE is a
26354 TEMPLATE_DECL node corresponding to the partial specialization, while
26355 the TI_ARGS is the set of template arguments that must be substituted
26356 into the template pattern in order to generate TARGET. The result is
26357 cached in the TI_PARTIAL_INFO of the corresponding TEMPLATE_INFO unless
26358 RECHECKING is true.
26360 If the choice of partial specialization is ambiguous, a diagnostic
26361 is issued, and the error_mark_node is returned. If there are no
26362 partial specializations matching TARGET, then NULL_TREE is
26363 returned, indicating that the primary template should be used. */
26365 tree
26368 {
26372 {
26377 }
26379 {
26383 }
26385 {
26390 }
26391 else
26398 && tinfo
26405 /* There are no partial specializations of this template. */
26411 /* For determining which partial specialization to use, only the
26412 innermost args are interesting. */
26415 {
26418 }
26420 /* The caller hasn't called push_to_top_level yet, but we need
26421 get_partial_spec_bindings to be done in non-template context so that we'll
26422 fully resolve everything. */
26423 processing_template_decl_sentinel ptds;
26427 {
26430 tree spec_tmpl;
26432 {
26433 /* Substitute in the template args from the enclosing class. */
26439 }
26440 else
26445 {
26449 /* Keep the candidate only if its constraints are satisfied. */
26452 }
26453 }
26461 {
26464 ;
26465 else
26466 {
26468 {
26471 {
26474 }
26475 }
26477 }
26478 }
26482 {
26485 {
26488 }
26489 }
26492 {
26497 auto_diagnostic_group d;
26500 else
26504 {
26509 }
26512 }
26518 }
26520 /* Explicitly instantiate DECL. */
26522 void
26524 {
26529 /* An error occurred, for which grokdeclarator has already issued
26530 an appropriate message. */
26533 {
26536 }
26542 {
26543 /* There is an asymmetry here in the way VAR_DECLs and
26544 FUNCTION_DECLs are handled by grokdeclarator. In the case of
26545 the latter, the DECL we get back will be marked as a
26546 template instantiation, and the appropriate
26547 DECL_TEMPLATE_INFO will be set up. This does not happen for
26548 VAR_DECLs so we do the lookup here. Probably, grokdeclarator
26549 should handle VAR_DECLs as it currently handles
26550 FUNCTION_DECLs. */
26552 {
26555 }
26558 {
26561 }
26563 {
26568 }
26569 }
26571 {
26574 }
26575 else
26578 /* Check for various error cases. Note that if the explicit
26579 instantiation is valid the RESULT will currently be marked as an
26580 *implicit* instantiation; DECL_EXPLICIT_INSTANTIATION is not set
26581 until we get here. */
26584 {
26585 /* DR 259 [temp.spec].
26587 Both an explicit instantiation and a declaration of an explicit
26588 specialization shall not appear in a program unless the explicit
26589 instantiation follows a declaration of the explicit specialization.
26591 For a given set of template parameters, if an explicit
26592 instantiation of a template appears after a declaration of an
26593 explicit specialization for that template, the explicit
26594 instantiation has no effect. */
26596 }
26598 {
26599 /* [temp.spec]
26601 No program shall explicitly instantiate any template more
26602 than once.
26604 We check DECL_NOT_REALLY_EXTERN so as not to complain when
26605 the first instantiation was `extern' and the second is not,
26606 and EXTERN_P for the opposite case. */
26609 /* If an "extern" explicit instantiation follows an ordinary
26610 explicit instantiation, the template is instantiated. */
26613 }
26615 {
26618 }
26620 {
26623 }
26626 ;
26628 {
26631 "ISO C++ 1998 forbids the use of %<extern%> on explicit "
26634 }
26635 else
26643 }
26645 static void
26647 {
26653 {
26656 }
26657 }
26659 /* Perform an explicit instantiation of template class T. STORAGE, if
26660 non-null, is the RID for extern, inline or static. COMPLAIN is
26661 nonzero if this is called from the parser, zero if called recursively,
26662 since the standard is unclear (as detailed below). */
26664 void
26666 {
26668 {
26672 else
26675 }
26680 {
26683 t);
26685 }
26687 /* At most one of these will be true. */
26693 {
26695 {
26698 "ISO C++ 1998 forbids the use of %<extern%> on "
26700 }
26701 else
26703 "ISO C++ forbids the use of %qE"
26712 else
26714 storage);
26715 }
26718 /* DR 259 [temp.spec].
26720 Both an explicit instantiation and a declaration of an explicit
26721 specialization shall not appear in a program unless the
26722 explicit instantiation follows a declaration of the explicit
26723 specialization.
26725 For a given set of template parameters, if an explicit
26726 instantiation of a template appears after a declaration of an
26727 explicit specialization for that template, the explicit
26728 instantiation has no effect. */
26732 {
26733 /* We've already instantiated the template. */
26735 /* [temp.spec]
26737 No program shall explicitly instantiate any template more
26738 than once.
26740 If EXTERN_P then this is ok. */
26746 }
26754 /* In contrast to implicit instantiation, where only the
26755 declarations, and not the definitions, of members are
26756 instantiated, we have here:
26758 [temp.explicit]
26760 An explicit instantiation that names a class template
26761 specialization is also an explicit instantiation of the same
26762 kind (declaration or definition) of each of its members (not
26763 including members inherited from base classes and members
26764 that are templates) that has not been previously explicitly
26765 specialized in the translation unit containing the explicit
26766 instantiation, provided that the associated constraints, if
26767 any, of that member are satisfied by the template arguments
26768 of the explicit instantiation. */
26772 && !static_p
26776 {
26781 }
26783 {
26789 }
26790 }
26792 /* Given a function DECL, which is a specialization of TMPL, modify
26793 DECL to be a re-instantiation of TMPL with the same template
26794 arguments. TMPL should be the template into which tsubst'ing
26795 should occur for DECL, not the most general template.
26797 One reason for doing this is a scenario like this:
26799 template <class T>
26800 void f(const T&, int i);
26802 void g() { f(3, 7); }
26804 template <class T>
26805 void f(const T& t, const int i) { }
26807 Note that when the template is first instantiated, with
26808 instantiate_template, the resulting DECL will have no name for the
26809 first parameter, and the wrong type for the second. So, when we go
26810 to instantiate the DECL, we regenerate it. */
26812 static void
26814 {
26815 /* The arguments used to instantiate DECL, from the most general
26816 template. */
26819 /* Make sure that we can see identifiers, and compute access correctly. */
26823 {
26824 tree specs;
26828 /* Don't bother with this for unique friends that can't be redeclared and
26829 might change type if regenerated (PR69836). */
26833 /* Use the source location of the definition. */
26841 /* Instantiate a dynamic exception-specification. noexcept will be
26842 handled below. */
26845 {
26851 specs);
26852 }
26854 /* Merge parameter declarations. */
26858 {
26865 }
26868 {
26869 /* If we're regenerating a specialization, the contracts will have
26870 been copied from the most general template. Replace those with
26871 the ones from the actual specialization. */
26874 {
26877 }
26880 }
26882 /* Merge additional specifiers from the CODE_PATTERN. */
26888 }
26890 {
26899 }
26900 else
26903 done:
26905 }
26907 /* Return the TEMPLATE_DECL into which DECL_TI_ARGS(DECL) should be
26908 substituted to get DECL. */
26910 tree
26912 {
26915 /* Set TMPL to the template whose DECL_TEMPLATE_RESULT is the pattern
26916 for the instantiation. This is not always the most general
26917 template. Consider, for example:
26919 template <class T>
26920 struct S { template <class U> void f();
26921 template <> void f<int>(); };
26923 and an instantiation of S<double>::f<int>. We want TD to be the
26924 specialization S<T>::f<int>, not the more general S<T>::f<U>. */
26926 more general template. */
26928 /* We must also deal with friend templates. Given:
26930 template <class T> struct S {
26931 template <class U> friend void f() {};
26932 };
26934 S<int>::f<U> say, is not an instantiation of S<T>::f<U>,
26935 so far as the language is concerned, but that's still
26936 where we get the pattern for the instantiation from. On
26937 other hand, if the definition comes outside the class, say:
26939 template <class T> struct S {
26940 template <class U> friend void f();
26941 };
26942 template <class U> friend void f() {}
26944 we don't need to look any further. That's what the check for
26945 DECL_INITIAL is for. */
26949 {
26950 /* The present template, TD, should not be a definition. If it
26951 were a definition, we should be using it! Note that we
26952 cannot restructure the loop to just keep going until we find
26953 a template with a definition, since that might go too far if
26954 a specialization was declared, but not defined. */
26956 /* Fetch the more general template. */
26958 }
26961 }
26963 /* Returns true if we need to instantiate this template instance even if we
26964 know we aren't going to emit it. */
26966 bool
26968 {
26969 /* We always instantiate inline functions so that we can inline them. An
26970 explicit instantiation declaration prohibits implicit instantiation of
26971 non-inline functions. With high levels of optimization, we would
26972 normally inline non-inline functions -- but we're not allowed to do
26973 that for "extern template" functions. Therefore, we check
26974 DECL_DECLARED_INLINE_P, rather than possibly_inlined_p. */
26978 /* And we need to instantiate static data members so that
26979 their initializers are available in integral constant
26980 expressions. */
26983 }
26985 /* If FN has a noexcept-specifier that hasn't been instantiated yet,
26986 instantiate it now, modifying TREE_TYPE (fn). Returns false on
26987 error, true otherwise. */
26989 bool
26991 {
26995 /* Don't instantiate a noexcept-specification from template context. */
27005 {
27007 /* We're in start_preparsed_function, keep going. */
27014 }
27025 /* For a member friend template we can get a TEMPLATE_DECL. Let's use
27026 its FUNCTION_DECL for the rest of this function -- push_access_scope
27027 doesn't accept TEMPLATE_DECLs. */
27029 {
27032 }
27035 {
27040 }
27042 {
27046 {
27049 /* This might have failed because of an unparsed DMI, so
27050 let's try again later. */
27052 }
27054 {
27055 /* If hash_set::add returns true, the element was already there. */
27060 fn);
27062 }
27064 {
27072 {
27073 /* If needed, set current_class_ptr for the benefit of
27074 tsubst_copy/PARM_DECL. */
27079 }
27081 /* If this function is represented by a TEMPLATE_DECL, then
27082 the deferred noexcept-specification might still contain
27083 dependent types, even after substitution. And we need the
27084 dependency check functions to work in build_noexcept_spec. */
27088 /* Do deferred instantiation of the noexcept-specifier. */
27092 /* Build up the noexcept-specification. */
27102 }
27103 else
27108 }
27111 {
27112 /* This failed with a hard error, so let's go with false. */
27115 }
27122 }
27124 /* We're starting to process the function INST, an instantiation of PATTERN;
27125 add their parameters to local_specializations. */
27127 void
27129 {
27133 {
27137 }
27139 {
27141 {
27144 }
27145 else
27146 {
27147 /* Register the (value) argument pack as a specialization of
27148 TMPL_PARM, then move on. */
27151 }
27152 }
27154 }
27156 /* Instantiate the body of D using PATTERN with ARGS. We have
27157 already determined PATTERN is the correct template to use.
27158 NESTED_P is true if this is a nested function, in which case
27159 PATTERN will be a FUNCTION_DECL not a TEMPLATE_DECL. */
27161 static void
27163 {
27168 {
27171 }
27172 else
27173 /* Only OMP reductions are nested. */
27185 {
27186 /* The variable might be a lambda's extra scope, and that
27187 lambda's visibility depends on D's. */
27190 }
27192 /* Mark D as instantiated so that recursive calls to
27193 instantiate_decl do not try to instantiate it again. */
27197 /* Regenerate the declaration in case the template has been modified
27198 by a subsequent redeclaration. */
27201 /* We already set the file and line above. Reset them now in case
27202 they changed as a result of calling regenerate_decl_from_template. */
27206 {
27207 /* Clear out DECL_RTL; whatever was there before may not be right
27208 since we've reset the type of the declaration. */
27212 /* The initializer is placed in DECL_INITIAL by
27213 regenerate_decl_from_template so we don't need to
27214 push/pop_access_scope again here. Pull it out so that
27215 cp_finish_decl can process it. */
27221 /* Clear DECL_EXTERNAL so that cp_finish_decl will process the
27222 initializer. That function will defer actual emission until
27223 we have a chance to determine linkage. */
27226 /* Enter the scope of D so that access-checking works correctly. */
27236 }
27240 {
27241 /* Set up the list of local specializations. */
27245 /* Set up context. */
27248 else
27249 {
27253 }
27255 /* Create substitution entries for the parameters. */
27258 /* Substitute into the body of the function. */
27262 else
27263 {
27267 /* Set the current input_location to the end of the function
27268 so that finish_function knows where we are. */
27269 input_location
27272 /* Remember if we saw an infinite loop in the template. */
27273 current_function_infinite_loop
27275 }
27277 /* Finish the function. */
27280 else
27281 {
27284 }
27288 }
27290 /* We're not deferring instantiation any more. */
27298 }
27300 /* Produce the definition of D, a _DECL generated from a template. If
27301 DEFER_OK is true, then we don't have to actually do the
27302 instantiation now; we just have to do it sometime. Normally it is
27303 an error if this is an explicit instantiation but D is undefined.
27304 EXPL_INST_CLASS_MEM_P is true iff D is a member of an explicitly
27305 instantiated class template. */
27307 tree
27309 {
27311 tree gen_args;
27312 tree args;
27313 tree td;
27314 tree code_pattern;
27315 tree spec;
27316 tree gen_tmpl;
27322 /* This function should only be used to instantiate templates for
27323 functions and static member variables. */
27329 /* We may have a pending instantiation of D itself. */
27332 /* Variables are never deferred; if instantiation is required, they
27333 are instantiated right away. That allows for better code in the
27334 case that an expression refers to the value of the variable --
27335 if the variable has a constant value the referring expression can
27336 take advantage of that fact. */
27340 /* Don't instantiate cloned functions. Instead, instantiate the
27341 functions they cloned. */
27350 /* D has already been instantiated or explicitly specialized, so
27351 there's nothing for us to do here.
27353 It might seem reasonable to check whether or not D is an explicit
27354 instantiation, and, if so, stop here. But when an explicit
27355 instantiation is deferred until the end of the compilation,
27356 DECL_EXPLICIT_INSTANTIATION is set, even though we still need to do
27357 the instantiation. */
27360 /* Check to see whether we know that this template will be
27361 instantiated in some other file, as with "extern template"
27362 extension. */
27365 /* In general, we do not instantiate such templates. */
27372 /* We should already have the extra args. */
27376 /* And what's in the hash table should match D. */
27378 == d
27381 /* This needs to happen before any tsubsting. */
27387 /* Set TD to the template whose DECL_TEMPLATE_RESULT is the pattern
27388 for the instantiation. */
27393 {
27394 /* Look up an explicit specialization, if any. */
27397 {
27400 }
27401 }
27407 /* We should never be trying to instantiate a member of a class
27408 template or partial specialization. */
27413 /* In the case of a friend template whose definition is provided
27414 outside the class, we may have too many arguments. Drop the
27415 ones we don't need. The same is true for specializations. */
27416 args = get_innermost_template_args
27420 {
27426 }
27427 else
27428 {
27432 else
27434 }
27436 /* We may be in the middle of deferred access check. Disable it now. */
27439 /* Unless an explicit instantiation directive has already determined
27440 the linkage of D, remember that a definition is available for
27441 this entity. */
27451 /* If D is a member of an explicitly instantiated class template,
27452 and no definition is available, treat it like an implicit
27453 instantiation. */
27456 {
27457 /* Leave linkage flags alone on instantiations with anonymous
27458 visibility. */
27460 {
27463 }
27465 }
27467 /* Defer all other templates, unless we have been explicitly
27468 forbidden from doing so. */
27470 template. */
27471 ! pattern_defined
27472 /* If it's OK to postpone instantiation, do so. */
27473 || defer_ok
27474 /* If this is a static data member that will be defined
27475 elsewhere, we don't want to instantiate the entire data
27476 member, but we do want to instantiate the initializer so that
27477 we can substitute that elsewhere. */
27479 /* Handle here a deleted function too, avoid generating
27480 its body (c++/61080). */
27482 {
27483 /* The definition of the static data member is now required so
27484 we must substitute the initializer. */
27488 {
27489 tree ns;
27490 tree init;
27499 args,
27501 /* If instantiating the initializer involved instantiating this
27502 again, don't call cp_finish_decl twice. */
27504 {
27505 /* Make sure the initializer is still constant, in case of
27506 circular dependency (template/instantiate6.C). */
27507 const_init
27511 }
27515 }
27517 /* We restore the source position here because it's used by
27518 add_pending_template. */
27524 /* [temp.explicit]
27526 The definition of a non-exported function template, a
27527 non-exported member function template, or a non-exported
27528 member function or static data member of a class template
27529 shall be present in every translation unit in which it is
27530 explicitly instantiated. */
27534 /* If we're in unevaluated context, we just wanted to get the
27535 constant value; this isn't an odr use, so don't queue
27536 a full instantiation. */
27538 /* ??? Historically, we have instantiated inline functions, even
27539 when marked as "extern template". */
27542 }
27543 else
27544 {
27549 }
27556 }
27558 /* Run through the list of templates that we wish we could
27559 instantiate, and instantiate any we can. RETRIES is the
27560 number of times we retry pending template instantiation. */
27562 void
27564 {
27568 /* Instantiating templates may trigger vtable generation. This in turn
27569 may require further template instantiations. We place a limit here
27570 to avoid infinite loop. */
27572 {
27576 "template instantiation depth exceeds maximum of %d"
27577 " instantiating %q+D, possibly from virtual table generation"
27581 /* Pretend that we defined it. */
27584 }
27586 do
27587 {
27592 {
27597 {
27599 {
27614 }
27617 }
27618 else
27619 {
27622 {
27623 instantiation
27629 }
27633 }
27636 {
27637 /* If INSTANTIATION has been instantiated, then we don't
27638 need to consider it again in the future. */
27643 }
27644 else
27645 {
27648 }
27651 }
27653 }
27657 }
27659 /* Substitute ARGVEC into T, which is a list of initializers for
27660 either base class or a non-static data member. The TREE_PURPOSEs
27661 are DECLs, and the TREE_VALUEs are the initializer values. Used by
27662 instantiate_decl. */
27664 static tree
27666 {
27671 {
27672 tree decl;
27673 tree init;
27679 {
27680 tree expr;
27681 tree arg;
27683 /* Expand the base class expansion type into separate base
27684 classes. */
27686 tf_warning_or_error,
27687 NULL_TREE);
27691 /* We'll be building separate TREE_LISTs of arguments for
27692 each base. */
27698 /* Build a dummy EXPR_PACK_EXPANSION that will be used to
27699 expand each argument in the TREE_VALUE of t. */
27706 /* VOID_TYPE_NODE is used to indicate
27707 value-initialization. */
27708 {
27711 }
27712 else
27713 {
27714 /* Substitute parameter packs into each argument in the
27715 TREE_LIST. */
27718 {
27719 tree expanded_exprs;
27721 /* Expand the argument. */
27722 tree value;
27725 else
27726 {
27729 }
27730 expanded_exprs
27732 tf_warning_or_error,
27733 NULL_TREE);
27737 /* Prepend each of the expanded expressions to the
27738 corresponding TREE_LIST in EXPANDED_ARGUMENTS. */
27746 else
27751 }
27754 /* Reverse all of the TREE_LISTs in EXPANDED_ARGUMENTS,
27755 since we built them backwards. */
27757 {
27760 }
27761 }
27762 }
27765 {
27767 {
27771 }
27772 else
27773 {
27774 tree tmp;
27778 else
27792 /* If we had an initializer but it instantiated to nothing,
27793 value-initialize the object. This will only occur when
27794 the initializer was a pack expansion where the parameter
27795 packs used in that expansion were of length zero. */
27798 }
27802 {
27804 decl);
27806 }
27807 /* Look for a target constructor. */
27811 {
27814 {
27818 }
27820 }
27823 {
27825 /* Carry over the dummy TREE_TYPE node containing the source
27826 location. */
27830 }
27831 }
27832 }
27834 }
27836 /* Instantiate an enumerated type. TAG is the template type, NEWTAG
27837 is the instantiation (which should have been created with
27838 start_enum) and ARGS are the template arguments to use. */
27840 static void
27842 {
27843 tree e;
27849 {
27850 tree value;
27853 /* Note that in a template enum, the TREE_VALUE is the
27854 CONST_DECL, not the corresponding INTEGER_CST. */
27858 /* Give this enumeration constant the correct access. */
27861 /* Actually build the enumerator itself. Here we're assuming that
27862 enumerators can't have dependent attributes. */
27866 /* Attribute deprecated without an argument isn't sticky: it'll
27867 melt into a tree flag, so we need to propagate the flag here,
27868 since we just created a new enumerator. */
27871 }
27883 }
27885 /* DECL is a FUNCTION_DECL that is a template specialization. Return
27886 its type -- but without substituting the innermost set of template
27887 arguments. So, innermost set of template parameters will appear in
27888 the type. */
27890 tree
27892 {
27893 /* For a function, DECL_TI_TEMPLATE is partially instantiated. */
27895 }
27897 /* Return truthvalue if we're processing a template different from
27898 the last one involved in diagnostics. */
27899 bool
27901 {
27903 }
27905 /* Remember current template involved in diagnostics. */
27906 void
27908 {
27910 }
27914 {
27916 }
27918 /* Return TRUE if current_function_decl is being instantiated, false
27919 otherwise. */
27921 bool
27923 {
27927 }
27929 /* [temp.param] Check that template non-type parm TYPE is of an allowable
27930 type. Return false for ok, true for disallowed. Issue error and
27931 inform messages under control of COMPLAIN. */
27933 static bool
27935 {
27946 {
27948 {
27953 }
27955 }
27960 /* Fall through; before C++11 alias templates, a bound ttp
27963 /* Any other wildcard type not already handled above is allowed. */
27970 {
27978 {
27979 auto_diagnostic_group d;
27983 }
27985 }
27987 {
27992 }
27995 {
27998 else
28000 type);
28001 }
28003 }
28005 /* Returns true iff the noexcept-specifier for TYPE is value-dependent. */
28007 static bool
28009 {
28012 /* Treat DEFERRED_NOEXCEPT as non-dependent, since it doesn't
28013 affect overload resolution and treating it as dependent breaks
28014 things. Same for an unparsed noexcept expression. */
28021 }
28023 /* Returns TRUE if TYPE is dependent, in the sense of [temp.dep.type].
28024 Assumes that TYPE really is a type, and not the ERROR_MARK_NODE.*/
28026 static bool
28028 {
28029 tree scope;
28031 /* [temp.dep.type]
28033 A type is dependent if it is:
28035 -- a template parameter. Template template parameters are types
28036 for us (since TYPE_P holds true for them) so we handle
28037 them here. */
28041 /* -- a qualified-id with a nested-name-specifier which contains a
28042 class-name that names a dependent type or whose unqualified-id
28043 names a dependent type. */
28047 /* -- a cv-qualified type where the cv-unqualified type is
28048 dependent.
28049 No code is necessary for this bullet; the code below handles
28050 cv-qualified types, and we don't want to strip aliases with
28051 TYPE_MAIN_VARIANT because of DR 1558. */
28052 /* -- a compound type constructed from any dependent type. */
28060 {
28061 tree arg_type;
28066 arg_type;
28072 /* A value-dependent noexcept-specifier makes the type dependent. */
28075 }
28076 /* -- an array type constructed from any dependent type or whose
28077 size is specified by a constant expression that is
28078 value-dependent.
28080 We checked for type- and value-dependence of the bounds in
28081 compute_array_index_type, so TYPE_DEPENDENT_P is already set. */
28083 {
28088 }
28090 /* -- a template-id in which either the template name is a template
28091 parameter ... */
28094 /* ... or any of the template arguments is a dependent type or
28095 an expression that is type-dependent or value-dependent. */
28097 && (any_dependent_template_arguments_p
28101 /* All TYPEOF_TYPEs, DECLTYPE_TYPEs, and TRAIT_TYPEs are
28102 dependent; if the argument of the `typeof' expression is not
28103 type-dependent, then it should already been have resolved. */
28109 /* A template argument pack is dependent if any of its packed
28110 arguments are. */
28112 {
28117 }
28119 /* All TYPE_PACK_EXPANSIONs are dependent, because parameter packs must
28120 be template parameters. */
28130 /* The standard does not specifically mention types that are local
28131 to template functions or local classes, but they should be
28132 considered dependent too. For example:
28134 template <int I> void f() {
28135 enum E { a = I };
28136 S<sizeof (E)> s;
28137 }
28139 The size of `E' cannot be known until the value of `I' has been
28140 determined. Therefore, `E' must be considered dependent. */
28144 /* Don't use type_dependent_expression_p here, as it can lead
28145 to infinite recursion trying to determine whether a lambda
28146 nested in a lambda is dependent (c++/47687). */
28150 && (any_dependent_template_arguments_p
28154 /* Other types are non-dependent. */
28156 }
28158 /* Returns TRUE if TYPE is dependent, in the sense of
28159 [temp.dep.type]. Note that a NULL type is considered dependent. */
28161 bool
28163 {
28164 /* If there are no template parameters in scope, then there can't be
28165 any dependent types. */
28167 {
28168 /* If we are not processing a template, then nobody should be
28169 providing us with a dependent type. */
28174 }
28176 /* If the type is NULL, we have not computed a type for the entity
28177 in question; in that case, the type is dependent. */
28181 /* Erroneous types can be considered non-dependent. */
28185 /* If we have not already computed the appropriate value for TYPE,
28186 do so now. */
28188 {
28191 }
28194 }
28196 /* Returns TRUE if SCOPE is a dependent scope, in which we can't do any
28197 lookup. In other words, a dependent type that is not the current
28198 instantiation. */
28200 bool
28202 {
28205 }
28207 /* True if we might find more declarations in SCOPE during instantiation than
28208 we can when parsing the template. */
28210 bool
28212 {
28214 }
28216 /* T is a SCOPE_REF. Return whether it represents a non-static member of
28217 an unknown base of 'this' (and is therefore instantiation-dependent). */
28219 static bool
28221 {
28238 }
28240 /* T is a SCOPE_REF; return whether we need to consider it
28241 instantiation-dependent so that we can check access at instantiation
28242 time even though we know which member it resolves to. */
28244 static bool
28246 {
28254 else
28256 }
28258 /* Returns TRUE if the EXPRESSION is value-dependent, in the sense of
28259 [temp.dep.constexpr]. EXPRESSION is already known to be a constant
28260 expression. */
28262 /* Note that this predicate is not appropriate for general expressions;
28263 only constant expressions (that satisfy potential_constant_expression)
28264 can be tested for value dependence. */
28266 bool
28268 {
28272 /* A type-dependent expression is also value-dependent. */
28277 {
28279 /* A dependent member function of the current instantiation. */
28283 /* A dependent member function of the current instantiation. */
28290 /* A name that has not been looked up -- must be dependent. */
28294 /* A non-type template parm. */
28298 /* A non-type template parm. */
28304 /* A constant with literal type and is initialized
28305 with an expression that is value-dependent. */
28309 {
28312 /* __PRETTY_FUNCTION__ inside a template function is dependent
28313 on the name of the function. */
28315 /* It might be used in a template, but not a template
28316 function, in which case its DECL_VALUE_EXPR will be
28317 "top level". */
28320 }
28322 /* FIXME cp_finish_decl doesn't fold reference initializers. */
28324 /* We have a constexpr variable and we're processing a template. When
28325 there's lifetime extension involved (for which finish_compound_literal
28326 used to create a temporary), we'll not be able to evaluate the
28327 variable until instantiating, so pretend it's value-dependent. */
28339 /* These expressions are value-dependent if the type to which
28340 the cast occurs is dependent or the expression being casted
28341 is value-dependent. */
28342 {
28348 /* A functional cast has a list of operands. */
28351 {
28352 /* If there are no operands, it must be an expression such
28353 as "int()". This should not happen for aggregate types
28354 because it would form non-constant expressions. */
28359 }
28369 }
28374 /* FALLTHRU */
28377 /* A `sizeof' expression is value-dependent if the operand is
28378 type-dependent or is a pack expansion. */
28387 /* An 'encode' expression is value-dependent if the operand is
28388 type-dependent. */
28397 /* All instantiation-dependent expressions should also be considered
28398 value-dependent. */
28406 /* A NONTYPE_ARGUMENT_PACK is value-dependent if any packed argument
28407 is value-dependent. */
28414 {
28430 }
28441 {
28445 }
28448 /* Treat all requires-expressions as value-dependent so
28449 we don't try to fold them. */
28456 {
28463 {
28465 /* In a call to a constexpr member function, look through the
28466 implicit ADDR_EXPR on the object argument so that it doesn't
28467 cause the call to be considered value-dependent. We also
28468 look through it in potential_constant_expression. */
28475 }
28477 }
28484 {
28486 tree val;
28493 }
28496 /* Treat a GNU statement expression as dependent to avoid crashing
28497 under instantiate_non_dependent_expr; it can't be constant. */
28502 /* The second operand is a type, which type_dependent_expression_p
28503 (and therefore value_dependent_expression_p) doesn't want to see. */
28509 /* A constant expression is value-dependent if any subexpression is
28510 value-dependent. */
28512 {
28519 {
28523 {
28526 /* In some cases, some of the operands may be missing.
28527 (For example, in the case of PREDECREMENT_EXPR, the
28528 amount to increment by may be missing.) That doesn't
28529 make the expression dependent. */
28532 }
28533 }
28537 }
28539 }
28541 /* The expression is not value-dependent. */
28543 }
28545 /* Returns TRUE if the EXPRESSION is type-dependent, in the sense of
28546 [temp.dep.expr]. Note that an expression with no type is
28547 considered dependent. Other parts of the compiler arrange for an
28548 expression with type-dependent subexpressions to have no type, so
28549 this function doesn't have to be fully recursive. */
28551 bool
28553 {
28564 /* An unresolved name is always dependent. */
28570 /* A lambda-expression in template context is dependent. dependent_type_p is
28571 true for a lambda in the scope of a class or function template, but that
28572 doesn't cover all template contexts, like a default template argument. */
28576 /* A fold expression is type-dependent. */
28583 /* Some expression forms are never type-dependent. */
28596 /* The types of these expressions depends only on the type to which
28597 the cast occurs. */
28606 /* The types of these expressions depends only on the type created
28607 by the expression. */
28610 {
28611 /* For NEW_EXPR tree nodes created inside a template, either
28612 the object type itself or a TREE_LIST may appear as the
28613 operand 1. */
28616 /* This is an array type. We need to check array dimensions
28617 as well. */
28619 || value_dependent_expression_p
28621 /* Array type whose dimension has to be deduced. */
28625 else
28627 }
28630 {
28634 /* 14.6.2.2 [temp.dep.expr]: An id-expression is type-dependent if it
28635 contains an identifier associated by name lookup with one or more
28636 declarations declared with a dependent type, or...a
28637 nested-name-specifier or qualified-id that names a member of an
28638 unknown specialization. */
28641 }
28651 {
28656 }
28658 /* A static data member of the current instantiation with incomplete
28659 array type is type-dependent, as the definition and specializations
28660 can have different bounds. */
28667 /* An array of unknown bound depending on a variadic parameter, eg:
28669 template<typename... Args>
28670 void foo (Args... args)
28671 {
28672 int arr[] = { args... };
28673 }
28675 template<int... vals>
28676 void bar ()
28677 {
28678 int arr[] = { vals... };
28679 }
28681 If the array has no length and has an initializer, it must be that
28682 we couldn't determine its length in cp_complete_array_type because
28683 it is dependent. */
28691 /* Pull a FUNCTION_DECL out of a BASELINK if we can. */
28693 {
28698 }
28700 /* A function or variable template-id is type-dependent if it has any
28701 dependent template arguments. */
28705 {
28706 /* Consider the innermost template arguments, since those are the ones
28707 that come from the template-id; the template arguments for the
28708 enclosing class do not make it type-dependent unless they are used in
28709 the type of the decl. */
28711 && (any_dependent_template_arguments_p
28714 }
28716 /* Otherwise, if the function decl isn't from a dependent scope, it can't be
28717 type-dependent. Checking this is important for functions with auto return
28718 type, which looks like a dependent type. */
28727 {
28731 }
28733 /* Otherwise, its constraints could still depend on outer template parameters
28734 from its (dependent) scope. */
28736 /* As an optimization, check this cheaper sufficient condition first.
28737 (At this point we've established that we're looking at a member of
28738 a dependent class, so it makes sense to start treating say undeduced
28739 auto as dependent.) */
28744 /* Always dependent, on the number of arguments if nothing else. */
28749 {
28754 {
28760 }
28761 /* SCOPE_REF with non-null TREE_TYPE is always non-dependent. */
28766 {
28771 }
28774 {
28781 }
28790 }
28792 /* The type of a non-type template parm declared with a placeholder type
28793 depends on the corresponding template argument, even though
28794 placeholders are not normally considered dependent. */
28801 /* Dependent type attributes might not have made it from the decl to
28802 the type yet. */
28808 }
28810 /* [temp.dep.expr]/5: A class member access expression (5.2.5) is
28811 type-dependent if the expression refers to a member of the current
28812 instantiation and the type of the referenced member is dependent, or the
28813 class member access expression refers to a member of an unknown
28814 specialization.
28816 This function returns true if the OBJECT in such a class member access
28817 expression is of an unknown specialization. */
28819 bool
28821 {
28822 /* An IDENTIFIER_NODE can sometimes have a TREE_TYPE, but it's still
28823 dependent. */
28828 }
28830 /* walk_tree callback function for instantiation_dependent_expression_p,
28831 below. Returns non-zero if a dependent subexpression is found. */
28833 static tree
28836 {
28838 {
28839 /* We don't have to worry about decltype currently because decltype
28840 of an instantiation-dependent expr is a dependent type. This
28841 might change depending on the resolution of DR 1172. */
28844 }
28847 {
28848 /* Don't treat an argument list as dependent just because it has no
28849 TREE_TYPE. */
28860 /* We'll check value-dependence separately. */
28863 /* Handle expressions with type operands. */
28868 {
28873 {
28876 else
28877 {
28880 }
28881 }
28883 }
28887 /* In a template, finish_class_member_access_expr creates a
28888 COMPONENT_REF with an IDENTIFIER_NODE for op1 even if it isn't
28889 type-dependent, so that we can check access control at
28890 instantiation time (PR 42277). See also Core issue 1273. */
28897 else
28900 /* Treat statement-expressions as dependent. */
28904 /* Treat requires-expressions as dependent. */
28915 /* Before C++17, a noexcept-specifier isn't part of the function type
28916 so it doesn't affect type dependence, but we still want to consider it
28917 for instantiation dependence. */
28926 }
28930 else
28932 }
28934 /* Returns TRUE if the EXPRESSION is instantiation-dependent, in the
28935 sense defined by the ABI:
28937 "An expression is instantiation-dependent if it is type-dependent
28938 or value-dependent, or it has a subexpression that is type-dependent
28939 or value-dependent."
28941 Except don't actually check value-dependence for unevaluated expressions,
28942 because in sizeof(i) we don't care about the value of i. Checking
28943 type-dependence will in turn check value-dependence of array bounds/template
28944 arguments as needed. */
28946 bool
28948 {
28949 tree result;
28960 }
28962 /* As above, but also check value-dependence of the expression as a whole. */
28964 bool
28966 {
28968 || (processing_template_decl
28971 }
28973 /* Like type_dependent_expression_p, but it also works while not processing
28974 a template definition, i.e. during substitution or mangling. */
28976 bool
28978 {
28984 }
28986 /* Returns TRUE if ARGS contains a type-dependent expression. */
28988 bool
28990 {
28999 }
29001 /* Returns TRUE if LIST (a TREE_LIST whose TREE_VALUEs are
29002 expressions) contains any type-dependent expressions. */
29004 bool
29006 {
29012 }
29014 /* Returns TRUE if LIST (a TREE_LIST whose TREE_VALUEs are
29015 expressions) contains any value-dependent expressions. */
29017 bool
29019 {
29025 }
29027 /* Returns TRUE if the ARG (a template argument) is dependent. */
29029 bool
29031 {
29035 /* Assume a template argument that was wrongly written by the user
29036 is dependent. This is consistent with what
29037 any_dependent_template_arguments_p [that calls this function]
29038 does. */
29048 {
29051 /* A member template of a dependent class is not necessarily
29052 type-dependent, but it is a dependent template argument because it
29053 will be a member of an unknown specialization to that template. */
29056 }
29058 {
29064 }
29067 else
29069 }
29071 /* Identify any expressions that use function parms. */
29073 static tree
29075 {
29078 {
29081 }
29083 }
29085 /* Returns true if a type specialization formed using the template
29086 arguments ARGS needs to use structural equality. */
29088 bool
29090 {
29100 {
29103 {
29109 {
29110 /* Look inside the argument pack. */
29113 }
29116 {
29125 /* An any_targ_node argument (added by add_defaults_to_ttp)
29126 makes the corresponding specialization not canonicalizable,
29127 since template_args_equal always return true for it. We
29128 may see this when called from bind_template_template_parm. */
29130 /* Checking current_function_decl because this structural
29131 comparison is only necessary for redeclaration. */
29134 && (cp_walk_tree_without_duplicates
29136 /* The identity of a class template specialization that uses
29137 a function parameter depends on the identity of the function.
29138 And if this specialization appeared in the trailing return
29139 type thereof, we don't know the identity of the function
29140 (e.g. if it's a redeclaration or a new function) until we
29141 form its signature and go through duplicate_decls. Thus
29142 it's unsafe to decide on a canonical type now (which depends
29143 on the DECL_CONTEXT of the function parameter, which can get
29144 mutated after the fact by duplicate_decls), so just require
29145 structural equality in this case (PR52830). */
29151 /* Require structural equality for specializations written
29152 in terms of a dependent alias template specialization. */
29157 /* Require structural equality for specializations written
29158 in terms of a class template specialization that itself
29159 needs structural equality. */
29161 }
29162 }
29163 }
29166 }
29168 /* Returns true if ARGS (a collection of template arguments) contains
29169 any dependent arguments. */
29171 bool
29173 {
29180 {
29185 }
29188 }
29190 /* Returns true if ARGS contains any errors. */
29192 bool
29194 {
29202 {
29205 else
29207 }
29213 {
29218 }
29221 }
29223 /* Returns TRUE if the template TMPL is type-dependent. */
29225 bool
29227 {
29229 {
29234 }
29236 /* Template template parameters are dependent. */
29240 /* So are names that have not been looked up. */
29244 }
29246 /* Returns TRUE if the specialization TMPL<ARGS> is dependent. */
29248 bool
29250 {
29253 }
29255 /* Returns TRUE if OMP_FOR with DECLV, INITV, CONDV and INCRV vectors
29256 are dependent. BODY is the body to use for loop transforming
29257 constructs. */
29259 bool
29261 {
29268 {
29275 {
29282 }
29303 {
29307 }
29311 {
29315 {
29321 /* If this loop has a class iterator with != comparison
29322 with increment other than i++/++i/i--/--i, make sure the
29323 increment is constant. */
29326 {
29329 else
29333 }
29334 }
29335 }
29336 }
29339 }
29341 /* TYPE is a TYPENAME_TYPE. Returns the ordinary TYPE to which the
29342 TYPENAME_TYPE corresponds. Returns the original TYPENAME_TYPE if
29343 no such TYPE can be found. Note that this function peers inside
29344 uninstantiated templates and therefore should be used only in
29345 extremely limited situations. ONLY_CURRENT_P restricts this
29346 peering to the currently open classes hierarchy (which is required
29347 when comparing types). */
29349 tree
29351 {
29352 tree scope;
29353 tree name;
29354 tree decl;
29356 tree pushed_scope;
29357 tree result;
29362 /* We shouldn't have built a TYPENAME_TYPE with a non-dependent scope. */
29365 /* Usually the non-qualified identifier of a TYPENAME_TYPE is
29366 TYPE_IDENTIFIER (type). But when 'type' is a typedef variant of a
29367 TYPENAME_TYPE node, then TYPE_NAME (type) is set to the TYPE_DECL
29368 representing the typedef. In that case TYPE_IDENTIFIER (type) is
29369 not the non-qualified identifier of the TYPENAME_TYPE anymore.
29370 So by getting the TYPE_IDENTIFIER of the _main declaration_ of
29371 the TYPENAME_TYPE instead, we avoid messing up with a possible
29372 typedef variant case. */
29375 /* If the SCOPE is itself a TYPENAME_TYPE, then we need to resolve
29376 it first before we can figure out what NAME refers to. */
29378 {
29380 /* Given a class template A with a dependent base with nested type C,
29381 typedef typename A::C::C C will land us here, as trying to resolve
29382 the initial A::C leads to the local C typedef, which leads back to
29383 A::C::C. So we break the recursion now. */
29385 else
29387 }
29388 /* If we don't know what SCOPE refers to, then we cannot resolve the
29389 TYPENAME_TYPE. */
29392 /* If this is a typedef, we don't want to look inside (c++/11987). */
29395 /* If SCOPE isn't the template itself, it will not have a valid
29396 TYPE_FIELDS list. */
29398 /* scope is either the template itself or a compatible instantiation
29399 like X<T>, so look up the name in the original template. */
29401 /* If scope has no fields, it can't be a current instantiation. Check this
29402 before currently_open_class to avoid infinite recursion (71515). */
29405 /* If the SCOPE is not the current instantiation, there's no reason
29406 to look inside it. */
29409 /* Enter the SCOPE so that name lookup will be resolved as if we
29410 were in the class definition. In particular, SCOPE will no
29411 longer be considered a dependent type. */
29413 /* Look up the declaration. */
29415 tf_warning_or_error);
29419 /* For a TYPENAME_TYPE like "typename X::template Y<T>", we want to
29420 find a TEMPLATE_DECL. Otherwise, we want to find a TYPE_DECL. */
29426 {
29430 }
29433 {
29434 /* Obtain the template and the arguments. */
29437 {
29438 /* We get here with a plain identifier because a previous tentative
29439 parse of the nested-name-specifier as part of a ptr-operator saw
29440 ::template X<A>. The use of ::template is necessary in a
29441 ptr-operator, but wrong in a declarator-id.
29443 [temp.names]: In a qualified-id of a declarator-id, the keyword
29444 template shall not appear at the top level. */
29448 }
29450 /* Instantiate the template. */
29456 }
29458 /* Leave the SCOPE. */
29462 /* If we failed to resolve it, return the original typename. */
29466 /* If lookup found a typename type, resolve that too. */
29468 {
29469 /* Ill-formed programs can cause infinite recursion here, so we
29470 must catch that. */
29474 }
29476 /* Qualify the resulting type. */
29482 }
29484 /* Returns a type which represents 'auto' or 'decltype(auto)'. We use a
29485 TEMPLATE_TYPE_PARM with a level one deeper than the actual template parms,
29486 by default. If set_canonical is true, we set TYPE_CANONICAL on it. */
29488 static tree
29490 {
29506 }
29508 tree
29510 {
29512 }
29514 tree
29516 {
29518 }
29520 /* Return a C++17 deduction placeholder for class template TMPL.
29521 There are represented as an 'auto' with the special level 0 and
29522 CLASS_PLACEHOLDER_TEMPLATE set. */
29524 tree
29526 {
29529 /* Our canonical type depends on the placeholder. */
29532 }
29534 /* True iff T is a C++17 class template deduction placeholder. */
29536 bool
29538 {
29540 }
29542 /* Return an auto for an explicit cast expression auto(x).
29543 Like CTAD placeholders, these have level 0 so that they're
29544 not accidentally replaced via tsubst and are always directly
29545 resolved via do_auto_deduction. */
29547 tree
29549 {
29551 }
29553 /* Make a "constrained auto" type-specifier. This is an auto or
29554 decltype(auto) type with constraints that must be associated after
29555 deduction. The constraint is formed from the given concept CON
29556 and its optional sequence of template arguments ARGS.
29558 TYPE must be the result of make_auto_type or make_decltype_auto_type. */
29560 static tree
29562 {
29563 /* Build the constraint. */
29575 /* Our canonical type depends on the constraint. */
29578 /* Attach the constraint to the type declaration. */
29580 }
29582 /* Make a "constrained auto" type-specifier. */
29584 tree
29586 {
29589 }
29591 /* Make a "constrained decltype(auto)" type-specifier. */
29593 tree
29595 {
29598 }
29600 /* Returns true if the placeholder type constraint T has any dependent
29601 (explicit) template arguments. */
29603 static bool
29605 {
29610 {
29613 }
29620 }
29622 /* Build and return a concept definition. Like other templates, the
29623 CONCEPT_DECL node is wrapped by a TEMPLATE_DECL. This returns the
29624 the TEMPLATE_DECL. */
29626 tree
29628 {
29634 /* A concept-definition shall not have associated constraints. */
29636 {
29639 }
29641 /* A concept-definition shall appear in namespace scope. Templates
29642 aren't allowed in block scope, so we only need to check for class
29643 scope. */
29645 {
29648 }
29651 {
29654 }
29656 /* Initially build the concept declaration; its type is bool. */
29666 /* Push the enclosing template. */
29668 }
29670 /* Given type ARG, return std::initializer_list<ARG>. */
29672 static tree
29674 {
29679 {
29683 "deducing from brace-enclosed initializer list"
29687 }
29693 }
29695 /* Replace auto in TYPE with std::initializer_list<auto>. */
29697 static tree
29699 {
29706 }
29708 /* Hash traits for hashing possibly constrained 'auto'
29709 TEMPLATE_TYPE_PARMs for use by do_auto_deduction. */
29712 {
29715 };
29717 /* Hash the 'auto' T. */
29719 inline hashval_t
29721 {
29723 /* Matching constrained-type-specifiers denote the same template
29724 parameter, so hash the constraint. */
29726 else
29727 /* But unconstrained autos are all separate, so just hash the pointer. */
29729 }
29731 /* Compare two 'auto's. */
29735 {
29742 /* Two unconstrained autos are distinct. */
29747 }
29749 /* The stem for deduction guide names. */
29752 /* Return the name for a deduction guide for class template TMPL. */
29754 tree
29756 {
29767 }
29769 /* True if NAME is the name of a deduction guide. */
29771 bool
29773 {
29777 }
29779 /* True if FN is a deduction guide. */
29781 bool
29783 {
29788 }
29790 /* True if FN is the copy deduction guide, i.e. A(A)->A. */
29792 bool
29794 {
29801 }
29803 /* True if FN is a guide generated from a constructor template. */
29805 bool
29807 {
29815 }
29817 /* True if FN is an aggregate initialization guide or the copy deduction
29818 guide. */
29820 bool
29822 {
29826 /* Explicitly declared. */
29829 /* Derived from a constructor. */
29832 }
29834 /* True if FN is a C++23 inherited guide. */
29836 bool
29838 {
29841 }
29843 /* Set the base class BASE from which the transformed guide FN
29844 was inherited as part of C++23 inherited CTAD. */
29846 static void
29848 {
29851 }
29853 /* OLDDECL is a _DECL for a template parameter. Return a similar parameter at
29854 LEVEL:INDEX, using tsubst_args and complain for substitution into non-type
29855 template parameter types. Note that the handling of template template
29856 parameters relies on current_template_parms being set appropriately for the
29857 new template. */
29859 static tree
29862 {
29868 tree newtype;
29871 {
29875 }
29876 else
29877 {
29880 {
29881 // Substitute once to fix references to other template parameters.
29884 // Now substitute again to reduce the level of the auto.
29887 }
29888 else
29891 }
29893 tree newdecl
29898 tree newidx;
29901 {
29910 {
29911 tree newresult
29916 // First create a copy (ttargs) of tsubst_args with an
29917 // additional level for the template template parameter's own
29918 // template parameters (ttparms).
29919 tree ttparms = (INNERMOST_TEMPLATE_PARMS
29927 // Substitute ttargs into ttparms to fix references to
29928 // other template parameters.
29931 // Now substitute again with args based on tparms, to reduce
29932 // the level of the ttparms.
29935 complain);
29936 // Finally, tack the adjusted parms onto tparms.
29939 // As with all template template parms, the parameter list captured
29940 // by this template template parm that corresponds to its own level
29941 // should be empty. This avoids infinite recursion when structurally
29942 // comparing two such rewritten template template parms (PR102479).
29947 // All done.
29951 }
29955 else
29957 }
29958 else
29959 {
29961 tree newconst
29973 }
29976 }
29978 /* As rewrite_template_parm, but for the whole TREE_LIST representing a
29979 template parameter. */
29981 static tree
29984 {
29999 }
30001 /* Returns a C++17 class deduction guide template based on the constructor
30002 CTOR. As a special case, CTOR can be a RECORD_TYPE for an implicit default
30003 guide, REFERENCE_TYPE for an implicit copy/move guide, or TREE_LIST for an
30004 aggregate initialization guide. OUTER_ARGS are the template arguments
30005 for the enclosing scope of the class. */
30007 static tree
30009 {
30013 location_t loc;
30017 {
30021 }
30024 {
30026 {
30030 else
30032 }
30035 else
30045 }
30046 else
30047 {
30053 fn_tmpl
30061 /* If type is a member class template, DECL_TI_ARGS (ctor) will have
30062 fully specialized args for the enclosing class. Strip those off, as
30063 the deduction guide won't have those template parameters. */
30066 /* Discard the 'this' parameter. */
30074 {
30077 /* For a member template constructor, we need to flatten the two
30078 template parameter lists into one, and then adjust the function
30079 signature accordingly. This gets...complicated. */
30082 /* For a member template we should have two levels of parms/args, one
30083 for the class and one for the constructor. We stripped
30084 specialized args for further enclosing classes above. */
30088 /* Template args for translating references to the two-level template
30089 parameters into references to the one-level template parameters we
30090 are creating. */
30095 /* Template parms for the constructor template. */
30098 /* Template parms for the class template. */
30102 /* Template parms for the deduction guide start as a copy of the
30103 template parms for the class. We set current_template_parms for
30104 lookup_template_class_1. */
30110 /* Now we need to rewrite the constructor parms to append them to the
30111 class parms. */
30113 {
30117 tree newelt
30123 }
30125 /* Now we have a final set of template parms to substitute into the
30126 function signature. */
30133 {
30135 /* FIXME: We'd like to avoid substituting outer template
30136 arguments into the constraint ahead of time, but the
30137 construction of tsubst_args assumes that outer arguments
30138 are already substituted in. */
30141 }
30143 /* Parms are to have DECL_CHAIN tsubsted, which would be skipped if
30144 cp_unevaluated_operand. */
30145 cp_evaluated ev;
30148 }
30149 else
30150 {
30151 /* Substitute in the same arguments to rewrite class members into
30152 references to members of an unknown specialization. */
30153 cp_evaluated ev;
30159 {
30161 /* FIXME: As above. */
30164 }
30165 }
30170 }
30173 {
30174 /* Copy the parms so we can set DECL_PRIMARY_TEMPLATE. */
30178 }
30182 FUNCTION_DECL,
30197 }
30199 /* Add to LIST the member types for the reshaped initializer CTOR. */
30201 static tree
30203 {
30207 {
30211 {
30217 }
30221 /* Give the trailing pack expansion parameter a default argument to
30222 match aggregate initialization behavior, even if we deduce the
30223 length of the pack separately to more than we have initializers. */
30225 /* if ei is of array type and xi is a braced-init-list or string literal,
30226 Ti is an rvalue reference to the declared type of ei */
30231 {
30233 ftype = cp_build_qualified_type
30235 ftype = (cp_build_reference_type
30237 }
30239 }
30242 }
30244 /* Return whether ETYPE is, or is derived from, a specialization of TMPL. */
30246 static bool
30248 {
30254 tree tparms = (INNERMOST_TEMPLATE_PARMS
30261 }
30263 /* Return a C++20 aggregate deduction candidate for TYPE initialized from
30264 INIT. */
30266 static tree
30268 {
30276 {
30282 }
30284 /* We might be creating a guide for a class member template, e.g.,
30286 template<typename U> struct A {
30287 template<typename T> struct B { T t; };
30288 };
30290 At this point, A will have been instantiated. Below, we need to
30291 use both A<U>::B<T> (TEMPLATE_TYPE) and A<int>::B<T> (TYPE) types. */
30292 const bool member_template_p
30296 tree template_type = (member_template_p
30302 /* No aggregate candidate for copy-initialization. */
30304 {
30308 }
30310 /* If we encounter a problem, we just won't add the candidate. */
30315 {
30320 }
30322 {
30325 {
30330 }
30332 len;
30334 {
30340 }
30341 }
30342 else
30343 /* Aggregate initialization doesn't apply to an initializer expression. */
30346 /* If we're creating a deduction guide for a member class template,
30347 we've used the original template pattern type for the reshape_init
30348 above; this is done because we want PARMS to be a template parameter
30349 type, something that can be deduced when used as a function template
30350 parameter. At this point the outer class template has already been
30351 partially instantiated (we deferred the deduction until the enclosing
30352 scope is non-dependent). Therefore we have to partially instantiate
30353 PARMS, so that its template level is properly reduced and we don't get
30354 mismatches when deducing types using the guide with PARMS. */
30356 {
30360 }
30363 {
30369 }
30372 }
30374 /* UGUIDES are the deduction guides for the underlying template of alias
30375 template TMPL; adjust them to be deduction guides for TMPL.
30377 This routine also handles C++23 inherited CTAD, in which case TMPL is a
30378 TREE_LIST representing a synthetic alias template whose TREE_PURPOSE is
30379 the template parameter list of the alias template (equivalently, of the
30380 derived class) and TREE_VALUE the defining-type-id (equivalently, the
30381 base whose guides we're inheriting). UGUIDES are the base's guides. */
30383 static tree
30385 {
30386 /* [over.match.class.deduct]: When resolving a placeholder for a deduced
30387 class type (9.2.8.2) where the template-name names an alias template A,
30388 the defining-type-id of A must be of the form
30390 typename(opt) nested-name-specifier(opt) template(opt) simple-template-id
30392 as specified in 9.2.8.2. The guides of A are the set of functions or
30393 function templates formed as follows. For each function or function
30394 template f in the guides of the template named by the simple-template-id
30395 of the defining-type-id, the template arguments of the return type of f
30396 are deduced from the defining-type-id of A according to the process in
30397 13.10.2.5 with the exception that deduction does not fail if not all
30398 template arguments are deduced. Let g denote the result of substituting
30399 these deductions into f. If substitution succeeds, form a function or
30400 function template f' with the following properties and add it to the set
30401 of guides of A:
30403 * The function type of f' is the function type of g.
30405 * If f is a function template, f' is a function template whose template
30406 parameter list consists of all the template parameters of A (including
30407 their default template arguments) that appear in the above deductions or
30408 (recursively) in their default template arguments, followed by the
30409 template parameters of f that were not deduced (including their default
30410 template arguments), otherwise f' is not a function template.
30412 * The associated constraints (13.5.2) are the conjunction of the
30413 associated constraints of g and a constraint that is satisfied if and only
30414 if the arguments of A are deducible (see below) from the return type.
30416 * If f is a copy deduction candidate (12.4.1.8), then f' is considered to
30417 be so as well.
30419 * If f was generated from a deduction-guide (12.4.1.8), then f' is
30420 considered to be so as well.
30422 * The explicit-specifier of f' is the explicit-specifier of g (if
30423 any). */
30428 {
30434 }
30435 else
30436 {
30443 }
30450 {
30457 {
30461 /* Deduce template arguments for f from the type-id of A. */
30467 /* CWG2664: Discard any deductions, still build the guide. */
30471 /* The number of parms for f' is the number of parms of A used in
30472 the deduced arguments plus non-deduced parms of f. */
30484 /* Set current_template_parms as in build_deduction_guide. */
30492 /* First copy over the used parms of A. */
30495 {
30498 {
30503 }
30504 }
30507 /* Adjust the deduced template args for f to refer to the A parms
30508 with their new indexes. */
30512 /* Now rewrite the non-deduced parms of f. */
30515 {
30522 }
30525 /* Substitute the deduced arguments plus the rewritten template
30526 parameters into f to get g. This covers the type, copyness,
30527 guideness, and explicit-specifier. */
30528 tree g;
30529 {
30530 /* Parms are to have DECL_CHAIN tsubsted, which would be skipped
30531 if cp_unevaluated_operand. */
30532 cp_evaluated ev;
30535 }
30540 {
30541 /* The targs are all non-dependent, so g isn't a template. */
30545 }
30554 /* Substitute the associated constraints. */
30557 {
30561 }
30565 /* Add a constraint that the return type matches the instantiation of
30566 A with the same template arguments. */
30569 /* Use template_args_equal instead of same_type_p to get the
30570 comparing_dependent_aliases behavior. */
30572 {
30575 }
30578 {
30581 }
30582 }
30583 else
30584 {
30585 /* For a non-template deduction guide, if the arguments of A aren't
30586 deducible from the return type, don't add the candidate. */
30587 non_template:
30591 }
30593 /* Rewrite the return type of the inherited guide in terms of the
30594 derived class. This is specified as replacing the return type R
30595 with typename CC<R>::type where the partially specialized CC maps a
30596 base class specialization to a specialization of the derived class
30597 having such a base (inducing substitution failure if no such derived
30598 class exists).
30600 As specified this mapping would be done at instantiation time using
30601 non-dependent template arguments, but we do it ahead of time using
30602 the generic arguments. This seems to be good enough since generic
30603 deduction should succeed only if concrete deduction would. */
30605 {
30624 }
30627 }
30630 }
30632 /* CTOR is a using-decl inheriting the constructors of some base of the class
30633 template TMPL; adjust the base's guides be deduction guides for TMPL. */
30635 static tree
30637 {
30638 /* [over.match.class.deduct]: In addition, if C is defined and inherits
30639 constructors ([namespace.udecl]) from a direct base class denoted in the
30640 base-specifier-list by a class-or-decltype B, let A be an alias template
30641 whose template parameter list is that of C and whose defining-type-id is
30642 B. If A is a deducible template ([dcl.type.simple]), the set contains the
30643 guides of A with the return type R of each guide replaced with typename
30644 CC::type given a class template
30646 template <typename> class CC;
30648 whose primary template is not defined and with a single partial
30649 specialization whose template parameter list is that of A and whose
30650 template argument list is a specialization of A with the template argument
30651 list of A ([temp.dep.type]) having a member typedef type designating a
30652 template specialization with the template argument list of A but with C as
30653 the template. */
30659 /* Recognize using B<T>::B::B as an inherited constructor. */
30660 /* FIXME: Also recognize using C::B::B? We might have to call
30661 resolve_typename_type for that. */
30673 }
30675 /* If template arguments for TMPL can be deduced from TYPE, return
30676 the deduced arguments, otherwise return NULL_TREE.
30677 Used to implement CPTK_IS_DEDUCIBLE for alias CTAD according to
30678 [over.match.class.deduct].
30680 This check is specified in terms of partial specialization, so the behavior
30681 should be parallel to that of get_partial_spec_bindings. */
30683 tree
30685 {
30688 {
30689 /* If tmpl is a class template, this is trivial: it's deducible if
30690 TYPE is a specialization of TMPL. */
30692 {
30697 else
30699 }
30701 /* Otherwise it's an alias template. */
30704 }
30705 else
30706 {
30707 /* TMPL is a synthetic alias template represented as a TREE_LIST as
30708 per alias_ctad_tweaks. */
30712 }
30718 again:
30723 /* We don't fail on an undeduced targ the second time through (like
30724 get_partial_spec_bindings) because we're going to try defaults. */
30727 {
30733 {
30738 }
30739 /* If the type parameter is a parameter pack, then it will be deduced
30740 to an empty parameter pack. This is another case that doesn't model
30741 well as partial specialization. */
30743 {
30744 tree arg;
30746 {
30749 }
30750 else
30754 }
30755 }
30757 /* Maybe add in default template args. This seems like a flaw in the
30758 specification in terms of partial specialization, since it says the
30759 partial specialization has the template parameter list of A, but a
30760 partial specialization can't have default targs. */
30765 /* I believe we don't need the template_template_parm_bindings_ok_p call
30766 because coerce_template_parms did coerce_template_template_parms. */
30772 }
30774 /* Return artificial deduction guides built from the constructors of class
30775 template TMPL. */
30777 static tree
30779 {
30786 {
30787 /* We handle C++23 inherited CTAD below. */
30793 }
30796 /* FIXME: CLASSTYPE_CONSTRUCTORS doesn't contain inherited constructors if
30797 e.g. the class also has a user-defined constructor. So instead iterate
30798 over TYPE_FIELDS manually to robustly find all relevant using-decls. */
30802 {
30806 }
30808 /* Add implicit default constructor deduction guide. */
30810 {
30812 complain);
30814 }
30816 /* Add copy guide. */
30817 {
30820 complain);
30822 }
30825 }
30829 /* Return the non-aggregate deduction guides for deducible template TMPL. The
30830 aggregate candidate is added separately because it depends on the
30831 initializer. Set ANY_DGUIDES_P if we find a non-implicit deduction
30832 guide. */
30834 static tree
30836 {
30839 {
30843 complain);
30844 }
30845 else
30846 {
30853 else
30855 }
30857 /* Cache the deduction guides for a template. We also remember the result of
30858 lookup, and rebuild everything if it changes; should be very rare. */
30859 /* FIXME: Also rebuild if this is a class template that inherits guides from a
30860 base class, and lookup for the latter changed. */
30864 {
30868 }
30869 else
30870 {
30873 }
30878 else
30879 {
30883 }
30887 }
30889 /* Return whether TMPL is a (class template argument-) deducible template. */
30891 bool
30893 {
30894 /* A deducible template is either a class template or is an alias template
30895 whose defining-type-id is of the form
30897 typename(opt) nested-name-specifier(opt) template(opt) simple-template-id
30899 where the nested-name-specifier (if any) is non-dependent and the
30900 template-name of the simple-template-id names a deducible template. */
30904 /* Don't consider CTAD for templates with the same name as a trait; that
30905 is ambiguous with e.g. __is_invocable(_Fn,_Args...). */
30916 }
30918 /* Deduce template arguments for the class template placeholder PTYPE for
30919 template TMPL based on the initializer INIT, and return the resulting
30920 type. */
30922 static tree
30925 {
30926 /* We should have handled this in the caller. */
30930 /* If the class was erroneous, don't try to deduce, because that
30931 can generate a lot of diagnostic. */
30937 /* Wait until the enclosing scope is non-dependent. */
30942 /* Initializing one placeholder from another. */
30953 {
30957 }
30959 {
30961 {
30962 /* Be permissive with equivalent alias templates. */
30964 auto_diagnostic_group d;
30966 bool complained
30968 "alias template deduction only available "
30973 {
30976 }
30977 }
30978 else
30980 }
30982 /* Wait until the initializer is non-dependent. */
30987 {
30991 {
30992 /* Substitute outer arguments into this CTAD template from the
30993 current instantiation. */
31000 }
31001 }
31003 /* Don't bother with the alias rules for an equivalent template. */
31016 {
31021 {
31022 /* As an exception, the first phase in 16.3.1.7 (considering the
31023 initializer list as a single argument) is omitted if the
31024 initializer list consists of a single expression of type cv U,
31025 where U is a specialization of C or a class derived from a
31026 specialization of C. */
31030 }
31033 else
31035 }
31038 else
31041 /* Do this now to avoid problems with erroneous args later on. */
31051 /* Prune explicit deduction guides in copy-initialization context (but
31052 not copy-list-initialization). */
31055 {
31061 {
31062 /* Found a nonconverting guide, prune the candidates. */
31069 }
31070 }
31078 /* If this is list-initialization and the class has a list guide, first
31079 try deducing from the list as a single argument, as [over.match.list]. */
31081 {
31089 {
31090 /* That didn't work, now try treating the list as a sequence of
31091 arguments. */
31097 }
31098 }
31101 {
31103 " of %qT, as it has no non-explicit deduction guides or "
31106 }
31108 {
31112 }
31118 {
31120 {
31121 auto_diagnostic_group d;
31127 }
31129 }
31130 /* [over.match.list]/1: In copy-list-initialization, if an explicit
31131 constructor is chosen, the initialization is ill-formed. */
31133 {
31135 {
31137 {
31138 // TODO: Pass down location from cp_finish_decl.
31139 auto_diagnostic_group d;
31141 "explicit deduction guide selected in "
31146 }
31148 }
31149 }
31151 /* If CTAD succeeded but the type doesn't have any explicit deduction
31152 guides, this deduction might not be what the user intended. */
31154 {
31155 auto_diagnostic_group d;
31159 "%qT may not intend to support class template argument "
31163 }
31167 }
31169 /* Return true if INIT is an unparenthesized id-expression or an
31170 unparenthesized class member access. Used for the argument of
31171 decltype(auto). */
31173 bool
31175 {
31178 /* We need to be able to tell '(r)' and 'r' apart (when it's of
31179 reference type). Only the latter is an id-expression. */
31187 }
31189 /* Replace occurrences of 'auto' in TYPE with the appropriate type deduced
31190 from INIT. AUTO_NODE is the TEMPLATE_TYPE_PARM used for 'auto' in TYPE.
31191 The CONTEXT determines the context in which auto deduction is performed
31192 and is used to control error diagnostics. FLAGS are the LOOKUP_* flags.
31194 OUTER_TARGS is used during template argument deduction (context == adc_unify)
31195 to properly substitute the result. It's also used in the adc_unify and
31196 adc_requirement contexts to communicate the necessary template arguments
31197 to satisfaction. OUTER_TARGS is ignored in other contexts.
31199 Additionally for adc_unify contexts TMPL is the template for which TYPE
31200 is a template parameter type.
31202 For partial-concept-ids, extra args from OUTER_TARGS, TMPL and the current
31203 scope may be appended to the list of deduced template arguments prior to
31204 determining constraint satisfaction as appropriate. */
31206 tree
31213 {
31219 /* Defining a subset of type-dependent expressions that we can deduce
31220 from ahead of time isn't worth the trouble. */
31223 /* Similarly, we can't deduce from another undeduced decl. */
31227 /* We may be doing a partial substitution, but we still want to replace
31228 auto_node. */
31232 {
31233 /* We don't recurse here because we can't deduce from a nested
31234 initializer_list. */
31238 }
31242 /* In C++23, we must deduce the type to int&& for code like
31243 decltype(auto) f(int&& x) { return (x); }
31244 or
31245 auto&& f(int x) { return x; }
31246 so we use treat_lvalue_as_rvalue_p. But don't do it for
31247 decltype(auto) f(int x) { return x; }
31248 where we should deduce 'int' rather than 'int&&'; transmogrifying
31249 INIT to an rvalue would break that. */
31250 tree r;
31260 /* C++17 class template argument deduction. */
31264 /* Nothing we can do with this, even in deduction context. */
31269 /* [dcl.spec.auto]: Obtain P from T by replacing the occurrences of auto
31270 with either a new invented type template parameter U or, if the
31271 initializer is a braced-init-list (8.5.4), with
31272 std::initializer_list<U>. */
31274 {
31279 else
31280 {
31282 {
31283 auto_diagnostic_group d;
31287 "for deduction to %<std::initializer_list%>, use copy-"
31289 }
31291 }
31292 }
31297 tree targs;
31301 {
31302 /* [dcl.struct.bind]/1 - if decomposition declaration has no ref-qualifiers
31303 and initializer has array type, deduce cv-qualified array type. */
31306 }
31308 {
31316 }
31317 else
31318 {
31329 DEDUCE_CALL,
31332 {
31334 /* Try again at instantiation time. */
31338 /* If type is error_mark_node a diagnostic must have been
31339 emitted by now. Also, having a mention to '<type error>'
31340 in the diagnostic is not really useful to the user. */
31341 {
31344 && (auto_node
31348 init);
31349 else
31352 DEDUCE_CALL,
31354 }
31356 }
31357 }
31359 /* Check any placeholder constraints against the deduced type. */
31363 {
31365 {
31370 /* If the constraint is dependent, we need to wait until
31371 instantiation time to resolve the placeholder. */
31374 }
31381 {
31385 {
31386 /* As in satisfy_declaration_constraints. */
31390 else
31392 }
31393 }
31400 /* HACK: Compensate for callers not always communicating all levels of
31401 outer template arguments by filling in the outermost missing levels
31402 with dummy levels before checking satisfaction. We'll still crash
31403 if the constraint depends on a template argument belonging to one of
31404 these missing levels, but this hack otherwise allows us to handle a
31405 large subset of possible constraints (including all non-dependent
31406 constraints). */
31409 {
31414 }
31417 {
31419 {
31420 auto_diagnostic_group d;
31422 {
31440 }
31442 }
31444 }
31445 }
31448 {
31449 /* Substitute this level-less auto via tsubst by temporarily
31450 overriding its level to 1. */
31455 }
31458 /* The outer template arguments are already substituted into type
31465 }
31467 /* Substitutes LATE_RETURN_TYPE for 'auto' in TYPE and returns the
31468 result. */
31470 tree
31472 {
31474 {
31477 }
31481 {
31482 /* In an abbreviated function template we didn't know we were dealing
31483 with a function template when we saw the auto return type, so rebuild
31484 the return type using an auto with the correct level. */
31489 auto_vec);
31490 /* Also rebuild the constraint info in terms of the new auto. */
31498 }
31500 }
31502 /* Returns true iff TYPE is a TEMPLATE_TYPE_PARM representing 'auto' or
31503 'decltype(auto)' or a deduced class template. */
31505 bool
31507 {
31512 else
31514 }
31516 /* for_each_template_parm callback for type_uses_auto. */
31518 int
31520 {
31522 }
31524 /* Returns the TEMPLATE_TYPE_PARM in TYPE representing `auto' iff TYPE contains
31525 a use of `auto'. Returns NULL_TREE otherwise. */
31527 tree
31529 {
31533 /* For parameter packs, check the contents of the pack. */
31538 }
31540 /* Recursively walk over && expressions searching for EXPR. Return a reference
31541 to that expression. */
31544 {
31548 {
31553 }
31555 }
31557 /* Convert the generic type parameters in PARM that match the types given in the
31558 range [START_IDX, END_IDX) from the current_template_parms into generic type
31559 packs. */
31561 tree
31563 {
31574 {
31575 /* Create a distinct parameter pack type from the current parm and add it
31576 to the replacement args to tsubst below into the generic function
31577 parameter. */
31591 /* Replace the current template parameter with new pack. */
31594 /* Surgically adjust the associated constraint of adjusted parameter
31595 and it's corresponding contribution to the current template
31596 requirements. */
31598 {
31601 /* Use UNKNOWN_LOCATION so write_template_args can tell the
31602 difference between this and a fold the user wrote. */
31605 TRUTH_ANDIF_EXPR);
31608 /* If there was a constraint, we also need to replace that in
31609 the template requirements, which we've already built. */
31613 }
31614 }
31620 /* If there are more levels then build up the replacement with the outer
31621 template parms. */
31625 replacement);
31628 }
31630 /* __integer_pack(N) in a pack expansion expands to a sequence of numbers from
31631 0..N-1. */
31633 void
31635 {
31638 integer_type_node,
31639 NULL_TREE),
31643 CP_BUILT_IN_INTEGER_PACK);
31644 }
31646 /* Walk the decl or type specialization table calling FN on each
31647 entry. */
31649 void
31653 {
31659 }
31661 /* Lookup the specialization of *ELT, in the decl or type
31662 specialization table. Return the SPEC that's already there, or
31663 NULL if nothing. */
31665 tree
31667 {
31676 }
31678 /* Return flags encoding whether SPEC is on the instantiation and/or
31679 specialization lists of TMPL. */
31681 unsigned
31683 {
31690 {
31693 }
31698 /* Only need to search if DECL is a partial specialization. */
31702 {
31705 }
31708 }
31710 /* Add a new specialization described by SPEC. DECL is the
31711 maybe-template decl and FLAGS is as returned from
31712 get_mergeable_specialization_flags. */
31714 void
31717 {
31719 {
31726 }
31727 else
31728 {
31731 /* We don't distinguish different constrained partial type
31732 specializations, so there could be duplicates. Everything else
31733 must be new. */
31735 {
31741 }
31742 }
31750 {
31751 /* A partial specialization. */
31757 }
31758 }
31760 /* Set up the hash tables for template instantiations. */
31762 void
31764 {
31770 }
31772 /* Print stats about the template hash tables for -fstats. */
31774 void
31776 {
31787 }
31789 #if CHECKING_P
31793 /* Verify that type_dependent_expression_p () works correctly, even
31794 in the presence of location wrapper nodes. */
31796 static void
31798 {
31803 /* If no templates are involved, nothing is type-dependent. */
31809 /* Within a template, an unresolved name is always type-dependent. */
31812 /* Ensure it copes with NULL_TREE and errors. */
31816 /* A USING_DECL in a template should be type-dependent, even if wrapped
31817 with a location wrapper (PR c++/83799). */
31826 }
31828 /* Run all of the selftests within this file. */
31830 void
31832 {
31834 }