| // RUN: %clang_cc1 -std=c++2a -x c++ -verify %s |
| |
| template<typename T> |
| constexpr bool is_ptr_v = false; |
| |
| template<typename T> |
| constexpr bool is_ptr_v<T*> = true; |
| |
| template<typename T, typename U> |
| constexpr bool is_same_v = false; |
| |
| template<typename T> |
| constexpr bool is_same_v<T, T> = true; |
| |
| template<typename T> requires is_ptr_v<T> // expected-note {{because 'is_ptr_v<int>' evaluated to false}} |
| // expected-note@-1{{because 'is_ptr_v<char>' evaluated to false}} |
| auto dereference(T t) { // expected-note {{candidate template ignored: constraints not satisfied [with T = int]}} |
| // expected-note@-1{{candidate template ignored: constraints not satisfied [with T = char]}} |
| return *t; |
| } |
| |
| static_assert(is_same_v<decltype(dereference<int*>(nullptr)), int>); |
| static_assert(is_same_v<decltype(dereference(2)), int>); // expected-error {{no matching function for call to 'dereference'}} |
| static_assert(is_same_v<decltype(dereference<char>('a')), char>); // expected-error {{no matching function for call to 'dereference'}} |
| |
| template<typename T> requires (T{} + T{}) // expected-note {{because substituted constraint expression is ill-formed: invalid operands to binary expression ('A' and 'A')}} |
| auto foo(T t) { // expected-note {{candidate template ignored: constraints not satisfied [with T = A]}} |
| return t + t; |
| } |
| |
| |
| template<typename T> requires (!((T{} - T{}) && (T{} + T{})) || false) |
| // expected-note@-1{{because substituted constraint expression is ill-formed: invalid operands to binary expression ('A' and 'A')}} |
| // expected-note@-2{{and 'false' evaluated to false}} |
| auto bar(T t) { // expected-note {{candidate template ignored: constraints not satisfied [with T = A]}} |
| return t + t; |
| } |
| |
| struct A { }; |
| |
| static_assert(foo(A{})); // expected-error {{no matching function for call to 'foo'}} |
| static_assert(bar(A{})); // expected-error {{no matching function for call to 'bar'}} |
