1 // RUN: %clang_cc1 -std=c++20 -verify %s
2
3 template <class T>
4 struct A {
5 void primary();
6 };
7
8 template <class T>
9 requires requires(T &t) { requires sizeof(t) > 4; }
10 struct A<T> {
11 void specialization1();
12 };
13
14 template <class T>
15 requires requires(T &t) { requires sizeof(t) > 8; }
16 struct A<T> {
17 void specialization2();
18 };
19
main()20 int main() {
21 A<char>().primary();
22 A<char[5]>().specialization1();
23 A<char[16]>(); // expected-error {{ambiguous partial specialization}}
24 // expected-note@10 {{partial specialization matches [with T = char[16]}}
25 // expected-note@16 {{partial specialization matches [with T = char[16]}}
26 }
27
28 // Check error messages when no overload with constraints matches.
29 template <class T>
foo()30 void foo()
31 requires requires(T &t) { requires sizeof(t) < 4; }
32 {}
33
34 template <class T>
foo()35 void foo()
36 requires requires(T &t) { requires sizeof(t) > 4; }
37 {}
38
39 template <class T>
foo()40 void foo()
41 requires requires(T &t) { requires sizeof(t) > 8; }
42 {}
43
test()44 void test() {
45 foo<char[4]>();
46 // expected-error@-1 {{no matching function for call to 'foo'}}
47 // expected-note@30 {{candidate template ignored: constraints not satisfied}}
48 // expected-note@31 {{because 'sizeof (t) < 4' (4 < 4) evaluated to false}}
49 // expected-note@35 {{candidate template ignored: constraints not satisfied}}
50 // expected-note@36 {{because 'sizeof (t) > 4' (4 > 4) evaluated to false}}
51 // expected-note@40 {{candidate template ignored: constraints not satisfied}}
52 // expected-note@41 {{because 'sizeof (t) > 8' (4 > 8) evaluated to false}}
53
54 foo<char[16]>();
55 // expected-error@-1 {{call to 'foo' is ambiguous}}
56 // expected-note@35 {{candidate function}}
57 // expected-note@40 {{candidate function}}
58 }
59