| // { dg-do compile { target c++17_only } } |
| // { dg-options "-fconcepts" } |
| |
| template <class X> concept bool allocatable = requires{{new X}->X *; }; |
| template <class X> concept bool semiregular = allocatable<X>; |
| template <class X> concept bool readable = requires{requires semiregular<X>;}; |
| template <class> int weak_input_iterator = requires{{0}->readable;}; |
| template <class X> bool input_iterator{weak_input_iterator<X>}; // { dg-prune-output "narrowing conversion" } |
| template <class X> bool forward_iterator{input_iterator<X>}; |
| template <class X> bool bidirectional_iterator{forward_iterator<X>}; |
| template <class X> |
| concept bool random_access_iterator{bidirectional_iterator<X>}; // { dg-error "constant" } |
| void fn1(random_access_iterator); |
| int main() { fn1(0); } // { dg-error "" } |
