| // RUN: %clang_cc1 -std=c++2a -x c++ %s -verify |
| |
| static_assert(requires { requires true; }); |
| |
| template<typename T> requires requires { requires false; } // expected-note{{because 'false' evaluated to false}} |
| struct r1 {}; |
| |
| using r1i = r1<int>; // expected-error{{constraints not satisfied for class template 'r1' [with T = int]}} |
| |
| template<typename T> requires requires { requires sizeof(T) == 0; } // expected-note{{because 'sizeof(int) == 0' (4 == 0) evaluated to false}} |
| struct r2 {}; |
| |
| using r2i = r2<int>; // expected-error{{constraints not satisfied for class template 'r2' [with T = int]}} |
| |
| template<typename T> requires requires (T t) { requires sizeof(t) == 0; } // expected-note{{because 'sizeof (t) == 0' (4 == 0) evaluated to false}} |
| struct r3 {}; |
| |
| using r3i = r3<int>; // expected-error{{constraints not satisfied for class template 'r3' [with T = int]}} |
| |
| template<typename T> |
| struct X { |
| template<typename U> requires requires (U u) { requires sizeof(u) == sizeof(T); } // expected-note{{because 'sizeof (u) == sizeof(T)' would be invalid: invalid application of 'sizeof' to an incomplete type 'void'}} |
| struct r4 {}; |
| }; |
| |
| using r4i = X<void>::r4<int>; // expected-error{{constraints not satisfied for class template 'r4' [with U = int]}} |
| |
| // C++ [expr.prim.req.nested] Examples |
| namespace std_example { |
| template<typename U> concept C1 = sizeof(U) == 1; // expected-note{{because 'sizeof(int) == 1' (4 == 1) evaluated to false}} |
| template<typename T> concept D = |
| requires (T t) { |
| requires C1<decltype (+t)>; // expected-note{{because 'decltype(+t)' (aka 'int') does not satisfy 'C1'}} |
| }; |
| |
| struct T1 { char operator+() { return 'a'; } }; |
| static_assert(D<T1>); |
| template<D T> struct D_check {}; // expected-note{{because 'short' does not satisfy 'D'}} |
| using dc1 = D_check<short>; // expected-error{{constraints not satisfied for class template 'D_check' [with T = short]}} |
| |
| template<typename T> |
| concept C2 = requires (T a) { |
| requires sizeof(a) == 4; // OK |
| requires a == 0; // expected-note{{because 'a == 0' would be invalid: constraint variable 'a' cannot be used in an evaluated context}} |
| }; |
| static_assert(C2<int>); // expected-note{{because 'int' does not satisfy 'C2'}} expected-error{{static_assert failed}} |
| } |