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   void foo(int) requires false {}
   6   // expected-note@-1 3{{because 'false' evaluated to false}}
   7   // expected-note@-2 {{candidate function not viable: constraints not satisfied}}
   8   void bar(int) requires true {}
   9
  10   void a(int);
  11   void a(double);
  12
  13   void baz() {
  14     foo(1); // expected-error{{no matching function for call to 'foo'}}
  15     bar(1);
  16     void (*p1)(int) = foo; // expected-error{{invalid reference to function 'foo': constraints not satisfied}}
  17     void (*p3)(int) = bar;
  18     decltype(foo)* a1 = nullptr; // expected-error{{invalid reference to function 'foo': constraints not satisfied}}
  19     decltype(bar)* a2 = nullptr;
  20   }
  21 }
  22
  23 namespace methods
  24 {
  25   template<typename T>
  26   struct A {
  27     static void foo(int) requires (sizeof(T) == 1) {} // expected-note 3{{because 'sizeof(char[2]) == 1' (2 == 1) evaluated to false}}
  28     static void bar(int) requires (sizeof(T) == 2) {} // expected-note 3{{because 'sizeof(char) == 2' (1 == 2) evaluated to false}}
  29     // Make sure the function body is not instantiated before constraints are checked.
  30     static auto baz(int) requires (sizeof(T) == 2) { return T::foo(); } // expected-note{{because 'sizeof(char) == 2' (1 == 2) evaluated to false}}
  31   };
  32
  33   void baz() {
  34     A<char>::foo(1);
  35     A<char>::bar(1); // expected-error{{invalid reference to function 'bar': constraints not satisfied}}
  36     A<char>::baz(1); // expected-error{{invalid reference to function 'baz': constraints not satisfied}}
  37     A<char[2]>::foo(1); // expected-error{{invalid reference to function 'foo': constraints not satisfied}}
  38     A<char[2]>::bar(1);
  39     void (*p1)(int) = A<char>::foo;
  40     void (*p2)(int) = A<char>::bar; // expected-error{{invalid reference to function 'bar': constraints not satisfied}}
  41     void (*p3)(int) = A<char[2]>::foo; // expected-error{{invalid reference to function 'foo': constraints not satisfied}}
  42     void (*p4)(int) = A<char[2]>::bar;
  43     decltype(A<char>::foo)* a1 = nullptr;
  44     decltype(A<char>::bar)* a2 = nullptr; // expected-error{{invalid reference to function 'bar': constraints not satisfied}}
  45     decltype(A<char[2]>::foo)* a3 = nullptr; // expected-error{{invalid reference to function 'foo': constraints not satisfied}}
  46     decltype(A<char[2]>::bar)* a4 = nullptr;
  47   }
  48 }
  49
  50 namespace operators
  51 {
  52   template<typename T>
  53   struct A {
  54     A<T> operator-(A<T> b) requires (sizeof(T) == 1) { return b; } // expected-note{{because 'sizeof(int) == 1' (4 == 1) evaluated to false}}
  55   };
  56
  57   void baz() {
  58     auto* x = &A<int>::operator-; // expected-error{{invalid reference to function 'operator-': constraints not satisfied}}
  59     auto y = &A<char>::operator-;
  60   }
  61 }