clang/test/CXX/expr/expr.prim/expr.prim.id/p4.cpp

   1 // RUN:  %clang_cc1 -std=c++2a -verify %s
   2
   3 namespace functions
   4 {
   5   template<typename T>
   6   struct S {
   7   static void foo(int) requires false {}
   8   // expected-note@-1 3{{because 'false' evaluated to false}}
   9   static void bar(int) requires true {}
  10   };
  11
  12   void a(int);
  13   void a(double);
  14
  15   void baz() {
  16     S<int>::foo(1); // expected-error{{invalid reference to function 'foo': constraints not satisfied}}
  17     S<int>::bar(1);
  18     void (*p1)(int) = S<int>::foo; // expected-error{{invalid reference to function 'foo': constraints not satisfied}}
  19     void (*p3)(int) = S<int>::bar;
  20     decltype(S<int>::foo)* a1 = nullptr; // expected-error{{invalid reference to function 'foo': constraints not satisfied}}
  21     decltype(S<int>::bar)* a2 = nullptr;
  22   }
  23 }
  24
  25 namespace methods
  26 {
  27   template<typename T>
  28   struct A {
  29     static void foo(int) requires (sizeof(T) == 1) {} // expected-note 3{{because 'sizeof(char[2]) == 1' (2 == 1) evaluated to false}}
  30     static void bar(int) requires (sizeof(T) == 2) {} // expected-note 3{{because 'sizeof(char) == 2' (1 == 2) evaluated to false}}
  31     // Make sure the function body is not instantiated before constraints are checked.
  32     static auto baz(int) requires (sizeof(T) == 2) { return T::foo(); } // expected-note{{because 'sizeof(char) == 2' (1 == 2) evaluated to false}}
  33   };
  34
  35   void baz() {
  36     A<char>::foo(1);
  37     A<char>::bar(1); // expected-error{{invalid reference to function 'bar': constraints not satisfied}}
  38     A<char>::baz(1); // expected-error{{invalid reference to function 'baz': constraints not satisfied}}
  39     A<char[2]>::foo(1); // expected-error{{invalid reference to function 'foo': constraints not satisfied}}
  40     A<char[2]>::bar(1);
  41     void (*p1)(int) = A<char>::foo;
  42     void (*p2)(int) = A<char>::bar; // expected-error{{invalid reference to function 'bar': constraints not satisfied}}
  43     void (*p3)(int) = A<char[2]>::foo; // expected-error{{invalid reference to function 'foo': constraints not satisfied}}
  44     void (*p4)(int) = A<char[2]>::bar;
  45     decltype(A<char>::foo)* a1 = nullptr;
  46     decltype(A<char>::bar)* a2 = nullptr; // expected-error{{invalid reference to function 'bar': constraints not satisfied}}
  47     decltype(A<char[2]>::foo)* a3 = nullptr; // expected-error{{invalid reference to function 'foo': constraints not satisfied}}
  48     decltype(A<char[2]>::bar)* a4 = nullptr;
  49   }
  50 }
  51
  52 namespace operators
  53 {
  54   template<typename T>
  55   struct A {
  56     A<T> operator-(A<T> b) requires (sizeof(T) == 1) { return b; } // expected-note{{because 'sizeof(int) == 1' (4 == 1) evaluated to false}}
  57   };
  58
  59   void baz() {
  60     auto* x = &A<int>::operator-; // expected-error{{invalid reference to function 'operator-': constraints not satisfied}}
  61     auto y = &A<char>::operator-;
  62   }
  63 }