1 // RUN: %clang_cc1 -std=c++2a -x c++ %s -verify
2 
3 bool r1 = requires () {};
4 // expected-error@-1 {{a requires expression must contain at least one requirement}}
5 
6 bool r2 = requires { requires true; };
7 
8 bool r3 = requires (int a, ...) { requires true; };
9 // expected-error@-1 {{varargs not allowed in requires expression}}
10 
11 template<typename... T>
12 bool r4 = requires (T... ts) { requires true; };
13 
14 bool r5 = requires (bool c, int d) { c; d; };
15 
16 bool r6 = requires (bool c, int d) { c; d; } && decltype(d){};
17 // expected-error@-1 {{use of undeclared identifier 'd'}}
18 
19 bool r7 = requires (bool c) { c; (requires (int d) { c; d; }); d; } && decltype(c){} && decltype(d){};
20 // expected-error@-1 2{{use of undeclared identifier 'd'}}
21 // expected-error@-2 {{use of undeclared identifier 'c'}}
22 
23 bool r8 = requires (bool, int) { requires true; };
24 
25 bool r9 = requires (bool a, int a) { requires true; };
26 // expected-error@-1 {{redefinition of parameter 'a'}}
27 // expected-note@-2 {{previous declaration is here}}
28 
29 bool r10 = requires (struct new_struct { int x; } s) { requires true; };
30 // expected-error@-1 {{'new_struct' cannot be defined in a parameter type}}
31 
32 bool r11 = requires (int x(1)) { requires true; };
33 // expected-error@-1 {{expected parameter declarator}}
34 // expected-error@-2 {{expected ')'}}
35 // expected-note@-3 {{to match this '('}}
36 
37 bool r12 = requires (int x = 10) { requires true; };
38 // expected-error@-1 {{default arguments not allowed for parameters of a requires expression}}
39 
40 bool r13 = requires (int f(int)) { requires true; };
41 
42 bool r14 = requires (int (*f)(int)) { requires true; };
43 
44 bool r15 = requires (10) { requires true; };
45 // expected-error@-1 {{expected parameter declarator}}
46 
47 bool r16 = requires (auto x) { requires true; };
48 // expected-error@-1 {{'auto' not allowed in requires expression parameter}}
49 
50 bool r17 = requires (auto [x, y]) { requires true; };
51 // expected-error@-1 {{'auto' not allowed in requires expression parameter}}
52 // expected-error@-2 {{use of undeclared identifier 'x'}}
53 
54 using a = int;
55 
56 bool r18 = requires { typename a; };
57 
58 bool r19 = requires { typename ::a; };
59 
60 template<typename T> struct identity { using type = T; };
61 
62 template<typename T> using identity_t = T;
63 
64 bool r20 = requires {
65     typename identity<int>::type;
66     typename identity<int>;
67     typename ::identity_t<int>;
68 };
69 
70 struct s { bool operator==(const s&); ~s(); };
71 
72 bool r21 = requires { typename s::operator==; };
73 // expected-error@-1 {{expected an identifier or template-id after '::'}}
74 
75 bool r22 = requires { typename s::~s; };
76 // expected-error@-1 {{expected an identifier or template-id after '::'}}
77 
78 template<typename T>
79 bool r23 = requires { typename identity<T>::temp<T>; };
80 // expected-error@-1 {{use 'template' keyword to treat 'temp' as a dependent template name}}
81 
82 template<typename T>
83 bool r24 = requires {
84     typename identity<T>::template temp<T>;
85     typename identity<T>::template temp; // expected-error{{expected an identifier or template-id after '::'}}
86 };
87 
88 bool r25 = requires { ; };
89 // expected-error@-1 {{expected expression}}
90 
91 bool r26 = requires { {}; };
92 // expected-error@-1 {{expected expression}}
93 
94 bool r27 = requires { { 0 } noexcept; };
95 
96 bool r28 = requires { { 0 } noexcept noexcept; };
97 // expected-error@-1 {{expected '->' before expression type requirement}}
98 // expected-error@-2 {{expected concept name with optional arguments}}
99 
100 template<typename T>
101 concept C1 = true;
102 
103 template<typename T, typename U>
104 concept C2 = true;
105 
106 bool r29 = requires { { 0 } noexcept C1; };
107 // expected-error@-1 {{expected '->' before expression type requirement}}
108 
109 bool r30 = requires { { 0 } noexcept -> C2<int>; };
110 
111 namespace ns { template<typename T> concept C = true; }
112 
113 bool r31 = requires { { 0 } noexcept -> ns::C; };
114 
115 template<typename T>
116 T i1 = 0;
117 
118 bool r32 = requires { requires false, 1; };
119 // expected-error@-1 {{expected ';' at end of requirement}}
120 
121 bool r33 = requires { 0 noexcept; };
122 // expected-error@-1 {{'noexcept' can only be used in a compound requirement (with '{' '}' around the expression)}}
123 
124 bool r34 = requires { 0 int; };
125 // expected-error@-1 {{expected ';' at end of requirement}}
126 
127 bool r35 = requires { requires true };
128 // expected-error@-1 {{expected ';' at end of requirement}}
129 
130 bool r36 = requires (bool b) { requires sizeof(b) == 1; };
131 
132 void r37(bool b) requires requires { 1 } {}
133 // expected-error@-1 {{expected ';' at end of requirement}}
134 
135 bool r38 = requires { requires { 1; }; };
136 // expected-warning@-1 {{this requires expression will only be checked for syntactic validity; did you intend to place it in a nested requirement? (add another 'requires' before the expression)}}
137 
138 bool r39 = requires { requires () { 1; }; };
139 // expected-warning@-1 {{this requires expression will only be checked for syntactic validity; did you intend to place it in a nested requirement? (add another 'requires' before the expression)}}
140 
141 bool r40 = requires { requires (int i) { i; }; };
142 // expected-warning@-1 {{this requires expression will only be checked for syntactic validity; did you intend to place it in a nested requirement? (add another 'requires' before the expression)}}
143 
144 bool r41 = requires { requires (); };
145 // expected-error@-1 {{expected expression}}
146