1*67c608a9SSaar Raz // RUN: %clang_cc1 -std=c++2a -x c++ -verify %s 2fdf80e86SSaar Raz 3fdf80e86SSaar Raz template<typename T> 4fdf80e86SSaar Raz constexpr bool is_ptr_v = false; 5fdf80e86SSaar Raz 6fdf80e86SSaar Raz template<typename T> 7fdf80e86SSaar Raz constexpr bool is_ptr_v<T*> = true; 8fdf80e86SSaar Raz 9fdf80e86SSaar Raz template<typename T, typename U> 10fdf80e86SSaar Raz constexpr bool is_same_v = false; 11fdf80e86SSaar Raz 12fdf80e86SSaar Raz template<typename T> 13fdf80e86SSaar Raz constexpr bool is_same_v<T, T> = true; 14fdf80e86SSaar Raz 15fdf80e86SSaar Raz template<typename T> requires is_ptr_v<T> // expected-note {{because 'is_ptr_v<int>' evaluated to false}} 16fdf80e86SSaar Raz // expected-note@-1{{because 'is_ptr_v<char>' evaluated to false}} dereference(T t)17fdf80e86SSaar Razauto dereference(T t) { // expected-note {{candidate template ignored: constraints not satisfied [with T = int]}} 18fdf80e86SSaar Raz // expected-note@-1{{candidate template ignored: constraints not satisfied [with T = char]}} 19fdf80e86SSaar Raz return *t; 20fdf80e86SSaar Raz } 21fdf80e86SSaar Raz 22fdf80e86SSaar Raz static_assert(is_same_v<decltype(dereference<int*>(nullptr)), int>); 23fdf80e86SSaar Raz static_assert(is_same_v<decltype(dereference(2)), int>); // expected-error {{no matching function for call to 'dereference'}} 24fdf80e86SSaar Raz static_assert(is_same_v<decltype(dereference<char>('a')), char>); // expected-error {{no matching function for call to 'dereference'}} 25fdf80e86SSaar Raz 26b65b1f32SSaar Raz template<typename T> requires (T{} + T{}) // expected-note {{because substituted constraint expression is ill-formed: invalid operands to binary expression ('A' and 'A')}} foo(T t)27fdf80e86SSaar Razauto foo(T t) { // expected-note {{candidate template ignored: constraints not satisfied [with T = A]}} 28fdf80e86SSaar Raz return t + t; 29fdf80e86SSaar Raz } 30fdf80e86SSaar Raz 31fdf80e86SSaar Raz 32b65b1f32SSaar Raz template<typename T> requires (!((T{} - T{}) && (T{} + T{})) || false) 33fdf80e86SSaar Raz // expected-note@-1{{because substituted constraint expression is ill-formed: invalid operands to binary expression ('A' and 'A')}} 34fdf80e86SSaar Raz // expected-note@-2{{and 'false' evaluated to false}} bar(T t)35fdf80e86SSaar Razauto bar(T t) { // expected-note {{candidate template ignored: constraints not satisfied [with T = A]}} 36fdf80e86SSaar Raz return t + t; 37fdf80e86SSaar Raz } 38fdf80e86SSaar Raz 39fdf80e86SSaar Raz struct A { }; 40fdf80e86SSaar Raz 41fdf80e86SSaar Raz static_assert(foo(A{})); // expected-error {{no matching function for call to 'foo'}} 42fdf80e86SSaar Raz static_assert(bar(A{})); // expected-error {{no matching function for call to 'bar'}}