p3-1y.cpp revision 60e141e1f87211ca831de6821003d80fe20a06f3 
1// RUN: %clang_cc1 -fsyntax-only -verify %s -std=c++1y -DCXX1Y
2// RUN: %clang_cc1 -fsyntax-only -verify %s -std=c++11 -Wno-c++1y-extensions
3
4// FIXME: This is in p11 (?) in C++1y.
5void f() {
6  decltype(auto) a = a; // expected-error{{variable 'a' declared with 'auto' type cannot appear in its own initializer}}
7  if (decltype(auto) b = b) {} // expected-error {{variable 'b' declared with 'auto' type cannot appear in its own initializer}}
8  decltype(auto) c = ({ decltype(auto) d = c; 0; }); // expected-error {{variable 'c' declared with 'auto' type cannot appear in its own initializer}}
9}
10
11void g() {
12  decltype(auto) a; // expected-error{{declaration of variable 'a' with type 'decltype(auto)' requires an initializer}}
13
14  decltype(auto) *b; // expected-error{{cannot form pointer to 'decltype(auto)'}} expected-error{{declaration of variable 'b' with type 'decltype(auto) *' requires an initializer}}
15
16  if (decltype(auto) b) {} // expected-error {{must have an initializer}}
17  for (;decltype(auto) b;) {} // expected-error {{must have an initializer}}
18  while (decltype(auto) b) {} // expected-error {{must have an initializer}}
19  if (decltype(auto) b = true) { (void)b; }
20}
21
22decltype(auto) n(1,2,3); // expected-error{{initializer for variable 'n' with type 'decltype(auto)' contains multiple expressions}}
23
24namespace N
25{
26  // All of these are references, because a string literal is an lvalue.
27  decltype(auto) a = "const char (&)[19]", b = a, c = (a);
28}
29
30void h() {
31  decltype(auto) b = 42ULL;
32
33  for (decltype(auto) c = 0; c < b; ++c) {
34  }
35}
36
37template<typename T, typename U> struct same;
38template<typename T> struct same<T, T> {};
39
40void i() {
41  decltype(auto) x = 5;
42  decltype(auto) int r; // expected-error {{cannot combine with previous 'decltype(auto)' declaration specifier}} expected-error {{requires an initializer}}
43}
44
45namespace p3_example {
46  template<typename T, typename U> struct is_same_impl {
47    static const bool value = false;
48  };
49  template<typename T> struct is_same_impl<T, T> {
50    static const bool value = true;
51  };
52  template<typename T, typename U> constexpr bool is_same() {
53    return is_same_impl<T,U>::value;
54  }
55
56  auto x = 5;
57  const auto *v = &x, u = 6;
58  static auto y = 0.0;
59  auto int r;  // expected-warning {{storage class}} expected-error {{file-scope}}
60
61  static_assert(is_same<decltype(x), int>(), "");
62  static_assert(is_same<decltype(v), const int*>(), "");
63  static_assert(is_same<decltype(u), const int>(), "");
64  static_assert(is_same<decltype(y), double>(), "");
65
66#ifdef CXX1Y
67  auto f() -> int;
68  auto g() { return 0.0; }
69  auto h();
70
71  static_assert(is_same<decltype(f), int()>(), "");
72  static_assert(is_same<decltype(g), double()>(), "");
73#endif
74}
75