| // RUN: %clang_cc1 -fsyntax-only -std=c++20 -verify %s |
| |
| template <typename Iterator> class normal_iterator {}; |
| |
| template <typename From, typename To> struct is_convertible {}; |
| |
| template <typename From, typename To> |
| inline constexpr bool is_convertible_v = is_convertible<From, To>::value; // expected-error {{no member named 'value' in 'is_convertible<bool, bool>'}} |
| |
| template <typename From, typename To> |
| concept convertible_to = is_convertible_v<From, To>; // #1 |
| |
| template <typename IteratorL, typename IteratorR> |
| requires requires(IteratorL lhs, IteratorR rhs) { // #2 |
| { lhs == rhs } -> convertible_to<bool>; // #3 |
| } |
| constexpr bool compare(normal_iterator<IteratorL> lhs, normal_iterator<IteratorR> rhs) { // #4 |
| return false; |
| } |
| |
| class Object; |
| |
| void function() { |
| normal_iterator<Object *> begin, end; |
| compare(begin, end); // expected-error {{no matching function for call to 'compare'}} #5 |
| } |
| |
| // expected-note@#1 {{in instantiation of variable template specialization 'is_convertible_v<bool, bool>' requested here}} |
| // expected-note@#1 {{substituting template arguments into constraint expression here}} |
| // expected-note@#3 {{checking the satisfaction of concept 'convertible_to<bool, bool>'}} |
| // expected-note@#2 {{substituting template arguments into constraint expression here}} |
| // expected-note@#5 {{checking constraint satisfaction for template 'compare<Object *, Object *>'}} |
| // expected-note@#5 {{in instantiation of function template specialization 'compare<Object *, Object *>' requested here}} |
| |
| // expected-note@#4 {{candidate template ignored: constraints not satisfied [with IteratorL = Object *, IteratorR = Object *]}} |
| // We don't know exactly the substituted type for `lhs == rhs`, thus a placeholder 'expr-type' is emitted. |
| // expected-note@#3 {{because 'convertible_to<expr-type, bool>' would be invalid}} |
