clang/test/Parser/cxx2a-concepts-requires-expr.cpp

   1 // RUN: %clang_cc1 -std=c++2a -x c++ %s -verify
   2
   3 bool r1 = requires () {};
   4 // expected-error@-1 {{a requires expression must contain at least one requirement}}
   5
   6 bool r2 = requires { requires true; };
   7
   8 bool r3 = requires (int a, ...) { requires true; };
   9 // expected-error@-1 {{varargs not allowed in requires expression}}
  10
  11 template<typename... T>
  12 bool r4 = requires (T... ts) { requires true; };
  13
  14 bool r5 = requires (bool c, int d) { c; d; };
  15
  16 bool r6 = requires (bool c, int d) { c; d; } && decltype(d){};
  17 // expected-error@-1 {{use of undeclared identifier 'd'}}
  18
  19 bool r7 = requires (bool c) { c; (requires (int d) { c; d; }); d; } && decltype(c){} && decltype(d){};
  20 // expected-error@-1 2{{use of undeclared identifier 'd'}}
  21 // expected-error@-2 {{use of undeclared identifier 'c'}}
  22
  23 bool r8 = requires (bool, int) { requires true; };
  24
  25 bool r9 = requires (bool a, int a) { requires true; };
  26 // expected-error@-1 {{redefinition of parameter 'a'}}
  27 // expected-note@-2 {{previous declaration is here}}
  28
  29 bool r10 = requires (struct new_struct { int x; } s) { requires true; };
  30 // expected-error@-1 {{'new_struct' cannot be defined in a parameter type}}
  31
  32 bool r11 = requires (int x(1)) { requires true; };
  33 // expected-error@-1 {{expected parameter declarator}}
  34 // expected-error@-2 {{expected ')'}}
  35 // expected-note@-3 {{to match this '('}}
  36
  37 bool r12 = requires (int x = 10) { requires true; };
  38 // expected-error@-1 {{default arguments not allowed for parameters of a requires expression}}
  39
  40 bool r13 = requires (int f(int)) { requires true; };
  41
  42 bool r14 = requires (int (*f)(int)) { requires true; };
  43
  44 bool r15 = requires (10) { requires true; };
  45 // expected-error@-1 {{expected parameter declarator}}
  46 // expected-error@-2 {{expected ')'}} expected-note@-2 {{to match}}
  47
  48 bool r16 = requires (auto x) { requires true; };
  49 // expected-error@-1 {{'auto' not allowed in requires expression parameter}}
  50
  51 bool r17 = requires (auto [x, y]) { requires true; };
  52 // expected-error@-1 {{'auto' not allowed in requires expression parameter}}
  53 // expected-error@-2 {{use of undeclared identifier 'x'}}
  54
  55 using a = int;
  56
  57 bool r18 = requires { typename a; };
  58
  59 bool r19 = requires { typename ::a; };
  60
  61 template<typename T> struct identity { using type = T; };
  62
  63 template<typename T> using identity_t = T;
  64
  65 bool r20 = requires {
  66     typename identity<int>::type;
  67     typename identity<int>;
  68     typename ::identity_t<int>;
  69 };
  70
  71 struct s { bool operator==(const s&); ~s(); };
  72
  73 bool r21 = requires { typename s::operator==; };
  74 // expected-error@-1 {{expected an identifier or template-id after '::'}}
  75
  76 bool r22 = requires { typename s::~s; };
  77 // expected-error@-1 {{expected an identifier or template-id after '::'}}
  78
  79 template<typename T>
  80 bool r23 = requires { typename identity<T>::temp<T>; };
  81 // expected-error@-1 {{use 'template' keyword to treat 'temp' as a dependent template name}}
  82
  83 template<typename T>
  84 bool r24 = requires {
  85     typename identity<T>::template temp<T>;
  86     typename identity<T>::template temp; // expected-error{{expected an identifier or template-id after '::'}}
  87 };
  88
  89 bool r25 = requires { ; };
  90 // expected-error@-1 {{expected expression}}
  91
  92 bool r26 = requires { {}; };
  93 // expected-error@-1 {{expected expression}}
  94
  95 bool r27 = requires { { 0 } noexcept; };
  96
  97 bool r28 = requires { { 0 } noexcept noexcept; };
  98 // expected-error@-1 {{expected '->' before expression type requirement}}
  99 // expected-error@-2 {{expected concept name with optional arguments}}
 100
 101 template<typename T>
 102 concept C1 = true;
 103
 104 template<typename T, typename U>
 105 concept C2 = true;
 106
 107 bool r29 = requires { { 0 } noexcept C1; };
 108 // expected-error@-1 {{expected '->' before expression type requirement}}
 109
 110 bool r30 = requires { { 0 } noexcept -> C2<int>; };
 111
 112 namespace ns { template<typename T> concept C = true; }
 113
 114 bool r31 = requires { { 0 } noexcept -> ns::C; };
 115
 116 template<typename T>
 117 T i1 = 0;
 118
 119 bool r32 = requires { requires false, 1; };
 120 // expected-error@-1 {{expected ';' at end of requirement}}
 121
 122 bool r33 = requires { 0 noexcept; };
 123 // expected-error@-1 {{'noexcept' can only be used in a compound requirement (with '{' '}' around the expression)}}
 124
 125 bool r34 = requires { 0 int; };
 126 // expected-error@-1 {{expected ';' at end of requirement}}
 127
 128 bool r35 = requires { requires true };
 129 // expected-error@-1 {{expected ';' at end of requirement}}
 130
 131 bool r36 = requires (bool b) { requires sizeof(b) == 1; };
 132
 133 void r37(bool b) requires requires { 1 } {}
 134 // expected-error@-1 {{expected ';' at end of requirement}}
 135
 136 bool r38 = requires { requires { 1; }; };
 137 // expected-error@-1 {{requires expression in requirement body; did you intend to place it in a nested requirement? (add another 'requires' before the expression)}}
 138
 139 bool r39 = requires { requires () { 1; }; };
 140 // expected-error@-1 {{requires expression in requirement body; did you intend to place it in a nested requirement? (add another 'requires' before the expression)}}
 141
 142 bool r40 = requires { requires (int i) { i; }; };
 143 // expected-error@-1 {{requires expression in requirement body; did you intend to place it in a nested requirement? (add another 'requires' before the expression)}}
 144
 145 bool r41 = requires { requires (); };
 146 // expected-error@-1 {{expected expression}}
 147
 148 bool r42 = requires { typename long; }; // expected-error {{expected a qualified name after 'typename'}}
 149
 150 template <int N>
 151 requires requires {
 152  typename _BitInt(N); // expected-error {{expected a qualified name after 'typename'}}
 153 } using r43 = void;
 154
 155 template <int N>
 156 using BitInt = _BitInt(N);
 157
 158 template <int N>
 159 requires requires {
 160  typename BitInt<N>; // ok
 161 } using r44 = void;