1 // RUN: %clang_cc1 -fsyntax-only -std=c++20 -verify %s
2 // RUN: %clang_cc1 -fsyntax-only -std=c++20 -verify %s -fexperimental-new-constant-interpreter
3
4 template <typename Iterator> class normal_iterator {};
5
6 template <typename From, typename To> struct is_convertible {};
7
8 template <typename From, typename To>
9 inline constexpr bool is_convertible_v = is_convertible<From, To>::value; // expected-error {{no member named 'value' in 'is_convertible<bool, bool>'}}
10
11 template <typename From, typename To>
12 concept convertible_to = is_convertible_v<From, To>; // #1
13
14 template <typename IteratorL, typename IteratorR>
15 requires requires(IteratorL lhs, IteratorR rhs) { // #2
16 { lhs == rhs } -> convertible_to<bool>; // #3
17 }
compare(normal_iterator<IteratorL> lhs,normal_iterator<IteratorR> rhs)18 constexpr bool compare(normal_iterator<IteratorL> lhs, normal_iterator<IteratorR> rhs) { // #4
19 return false;
20 }
21
22 class Object;
23
function()24 void function() {
25 normal_iterator<Object *> begin, end;
26 compare(begin, end); // expected-error {{no matching function for call to 'compare'}} #5
27 }
28
29 // expected-note@#1 {{in instantiation of variable template specialization 'is_convertible_v<bool, bool>' requested here}}
30 // expected-note@#1 {{substituting template arguments into constraint expression here}}
31 // expected-note@#3 {{checking the satisfaction of concept 'convertible_to<bool, bool>'}}
32 // expected-note@#2 {{substituting template arguments into constraint expression here}}
33 // expected-note@#5 {{checking constraint satisfaction for template 'compare<Object *, Object *>'}}
34 // expected-note@#5 {{in instantiation of function template specialization 'compare<Object *, Object *>' requested here}}
35
36 // expected-note@#4 {{candidate template ignored: constraints not satisfied [with IteratorL = Object *, IteratorR = Object *]}}
37 // We don't know exactly the substituted type for `lhs == rhs`, thus a placeholder 'expr-type' is emitted.
38 // expected-note@#3 {{because 'convertible_to<expr-type, bool>' would be invalid}}
39