1 //  { dg-additional-options "-fsyntax-only -fexceptions -w" }
2 
3 // Diagose bad traits traits : fake something faulty.
4 
5 namespace std {
6   // name is present, but not a template.
7   struct coroutine_traits {
8   };
9 }
10 
11 int
bad_coroutine(void)12 bad_coroutine (void)
13 {
14   co_yield 5; // { dg-error {coroutines require a traits template; cannot find 'std::coroutine_traits'} }
15   co_return;
16 }
17