clang/test/SemaTemplate/typename-specifier-3.cpp

   1 // RUN: %clang_cc1 -fsyntax-only -verify=expected,precxx17 %std_cxx11-14 %s
   2 // RUN: %clang_cc1 -fsyntax-only -verify=expected,cxx17 %std_cxx17- %s
   3
   4 // PR4364
   5 template<class T> struct a { // precxx17-note {{here}}
   6   T b() {
   7     return typename T::x();
   8   }
   9 };
  10 struct B {
  11   typedef B x;
  12 };
  13 B c() {
  14   a<B> x;
  15   return x.b();
  16 }
  17
  18 // Some extra tests for invalid cases
  19 template<class T> struct test2 { T b() { return typename T::a; } }; // expected-error{{expected '(' for function-style cast or type construction}}
  20 template<class T> struct test3 { T b() { return typename a; } }; // expected-error{{expected a qualified name after 'typename'}} cxx17-error{{expected '(' for function-style cast or type construction}}
  21 template<class T> struct test4 { T b() { return typename ::a; } }; // precxx17-error{{refers to non-type member}} expected-error{{expected '(' for function-style cast or type construction}}
  22
  23 // PR12884
  24 namespace PR12884_original {
  25   template <typename T> struct A {
  26     struct B {
  27       template <typename U> struct X {};
  28       typedef int arg;
  29     };
  30     struct C {
  31       typedef B::X<typename B::arg> x; // precxx17-warning{{missing 'typename' prior to dependent type name B::X; implicit 'typename' is a C++20 extension}}
  32     };
  33   };
  34
  35   template <> struct A<int>::B {
  36     template <int N> struct X {};
  37     static const int arg = 0;
  38   };
  39
  40   A<int>::C::x a;
  41 }
  42 namespace PR12884_half_fixed {
  43   template <typename T> struct A {
  44     struct B {
  45       template <typename U> struct X {};
  46       typedef int arg;
  47     };
  48     struct C {
  49       typedef typename B::X<typename B::arg> x; // expected-error {{use 'template'}} expected-error {{refers to non-type}}
  50     };
  51   };
  52
  53   template <> struct A<int>::B {
  54     template <int N> struct X {};
  55     static const int arg = 0; // expected-note {{here}}
  56   };
  57
  58   A<int>::C::x a; // expected-note {{here}}
  59 }
  60 namespace PR12884_fixed {
  61   template <typename T> struct A {
  62     struct B {
  63       template <typename U> struct X {};
  64       typedef int arg;
  65     };
  66     struct C {
  67       typedef typename B::template X<B::arg> x;
  68     };
  69   };
  70
  71   template <> struct A<int>::B {
  72     template <int N> struct X {};
  73     static const int arg = 0;
  74   };
  75
  76   A<int>::C::x a; // ok
  77 }