1 // Support parsing of concepts
2 
3 // RUN:  %clang_cc1 -std=c++20 -verify %s
4 template<typename T> concept C1 = true; // expected-note 2{{previous}}
5 
6 template<typename T> concept C1 = true; // expected-error{{redefinition}}
7 
8 template<concept T> concept D1 = true;
9 // expected-error@-1{{expected template parameter}}
10 // expected-error@-2{{concept template parameter list must have at least one parameter; explicit specialization of concepts is not allowed}}
11 
12 template<template<typename> concept T> concept D2 = true;
13 // expected-error@-1{{expected identifier}}
14 // expected-error@-2{{template template parameter requires 'class' after the parameter list}}
15 // expected-error@-3{{concept template parameter list must have at least one parameter; explicit specialization of concepts is not allowed}}
16 
17 struct S1 {
18   template<typename T> concept C1 = true; // expected-error {{concept declarations may only appear in global or namespace scope}}
19 };
20 
21 extern "C++" {
22   template<typename T> concept C1 = true; // expected-error{{redefinition}}
23 }
24 
25 template<typename A>
26 template<typename B>
27 concept C2 = true; // expected-error {{extraneous template parameter list in concept definition}}
28 
29 template<typename T> concept C3 = true; // expected-note {{previous}} expected-note {{previous}}
30 int C3; // expected-error {{redefinition}}
31 struct C3 {}; // expected-error {{redefinition}}
32 
33 struct C4 {}; // expected-note{{previous definition is here}}
34 template<typename T> concept C4 = true;
35 // expected-error@-1{{redefinition of 'C4' as different kind of symbol}}
36 
37 // TODO: Add test to prevent explicit specialization, partial specialization
38 // and explicit instantiation of concepts.
39 
40 template<typename T, T v>
41 struct integral_constant { static constexpr T value = v; };
42 
43 namespace N {
44   template<typename T> concept C5 = true;
45 }
46 using N::C5;
47 
48 template <bool word> concept C6 = integral_constant<bool, wor>::value;
49 // expected-error@-1{{use of undeclared identifier 'wor'; did you mean 'word'?}}
50 // expected-note@-2{{'word' declared here}}
51 
52 template<typename T> concept bool C7 = true;
53 // expected-warning@-1{{ISO C++20 does not permit the 'bool' keyword after 'concept'}}
54 
55 template<> concept C8 = false;
56 // expected-error@-1{{concept template parameter list must have at least one parameter; explicit specialization of concepts is not allowed}}
57 
58 template<> concept C7<int> = false;
59 // expected-error@-1{{name defined in concept definition must be an identifier}}
60 
61 template<typename T> concept N::C9 = false;
62 // expected-error@-1{{name defined in concept definition must be an identifier}}
63 
64 class A { };
65 // expected-note@-1{{'A' declared here}}
66 
67 template<typename T> concept A::C10 = false;
68 // expected-error@-1{{expected namespace name}}
69 
70 template<typename T> concept operator int = false;
71 // expected-error@-1{{name defined in concept definition must be an identifier}}
72 
73 template<bool x> concept C11 = 2; // expected-error {{atomic constraint must be of type 'bool' (found 'int')}}
74 template<bool x> concept C12 = 2 && x; // expected-error {{atomic constraint must be of type 'bool' (found 'int')}}
75 template<bool x> concept C13 = x || 2 || x; // expected-error {{atomic constraint must be of type 'bool' (found 'int')}}
76 template<bool x> concept C14 = 8ull && x || x; // expected-error {{atomic constraint must be of type 'bool' (found 'unsigned long long')}}
77 template<typename T> concept C15 = sizeof(T); // expected-error {{atomic constraint must be of type 'bool'}}
78 template<typename T> concept C16 = true && (0 && 0); // expected-error {{atomic constraint must be of type 'bool' (found 'int')}}
79 // expected-warning@-1{{use of logical '&&' with constant operand}}
80 // expected-note@-2{{use '&' for a bitwise operation}}
81 // expected-note@-3{{remove constant to silence this warning}}
82 template<typename T> concept C17 = T{};
83 static_assert(!C17<bool>);
84 template<typename T> concept C18 = (bool&&)true;
85 static_assert(C18<int>);
86 template<typename T> concept C19 = (const bool&)true;
87 static_assert(C19<int>);
88 template<typename T> concept C20 = (const bool)true;
89 static_assert(C20<int>);
90 template <bool c> concept C21 = integral_constant<bool, c>::value && true;
91 static_assert(C21<true>);
92 static_assert(!C21<false>);
93 template <bool c> concept C22 = integral_constant<bool, c>::value;
94 static_assert(C22<true>);
95 static_assert(!C22<false>);
96 
97 template <bool word> concept C23 = integral_constant<bool, wor>::value;
98 // expected-error@-1{{use of undeclared identifier 'wor'; did you mean 'word'?}}
99 // expected-note@-2{{'word' declared here}}
100 
101