p7-1y.cpp revision 732277ac26b0ad6cf6c78a039f8f504c2203261f 
1// RUN: %clang_cc1 -verify -std=c++1y %s
2
3namespace std {
4  template<typename T> struct initializer_list {
5    const T *p;
6    unsigned long n;
7    initializer_list(const T *p, unsigned long n);
8  };
9}
10
11int i;
12int &&f();
13
14using Int = int;
15using IntLRef = int&;
16using IntRRef = int&&;
17using InitListInt = std::initializer_list<int>;
18using IntPtr = int*;
19
20auto x3a = i;
21decltype(auto) x3d = i;
22using Int = decltype(x3a);
23using Int = decltype(x3d);
24
25auto x4a = (i);
26decltype(auto) x4d = (i);
27using Int = decltype(x4a);
28using IntLRef = decltype(x4d);
29
30auto x5a = f();
31decltype(auto) x5d = f();
32using Int = decltype(x5a);
33using IntRRef = decltype(x5d);
34
35auto x6a = { 1, 2 };
36decltype(auto) x6d = { 1, 2 }; // expected-error {{cannot deduce 'decltype(auto)' from initializer list}}
37using InitListInt = decltype(x6a);
38
39auto *x7a = &i;
40decltype(auto) *x7d = &i; // expected-error {{cannot form pointer to 'decltype(auto)'}}
41using IntPtr = decltype(x7a);
42
43struct S {};
44
45decltype(auto) f1();
46decltype(auto) (*f2)(); // expected-error {{'decltype(auto)' can only be used as a return type in a function declaration}} expected-error {{requires an initializer}}
47decltype(auto) *f3(); // expected-error {{cannot form pointer to 'decltype(auto)'}}
48const decltype(auto) f4(); // expected-error {{'decltype(auto)' cannot be combined with other type specifiers}}
49typedef decltype(auto) f5(); // expected-error {{'decltype(auto)' can only be used as a return type in a function declaration}}
50decltype(auto) ((((((f6))))())); // ok
51decltype(auto) f7()(); // expected-error {{'decltype(auto)' can only be used as a return type in a function declaration}} expected-error {{function cannot return function type}}
52decltype(auto) (S::*f8)(); // expected-error {{'decltype(auto)' can only be used as a return type in a function declaration}} expected-error {{requires an initializer}}
53decltype(auto) &f9(); // expected-error {{cannot form reference to 'decltype(auto)'}}
54decltype(auto) (&f10())[10]; // expected-error {{cannot form array of 'decltype(auto)'}}
55
56decltype(auto) ((((((v1)))))) = 0; // ok
57decltype(auto) v2[1] = { 0 }; // expected-error {{cannot form array of 'decltype(auto)'}}
58decltype(auto) &v3 = { 0 }; // expected-error {{cannot form reference to 'decltype(auto)'}}
59decltype(auto) *v4 = { 0 }; // expected-error {{cannot form pointer to 'decltype(auto)'}}
60
61auto multi1a = 0, &multi1b = multi1a;
62auto multi1c = multi1a, multi1d = multi1b;
63decltype(auto) multi1e = multi1a, multi1f = multi1b; // expected-error {{'decltype(auto)' deduced as 'int' in declaration of 'multi1e' and deduced as 'int &' in declaration of 'multi1f'}}
64
65auto f1a() { return 0; }
66decltype(auto) f1d() { return 0; }
67using Int = decltype(f1a());
68using Int = decltype(f1d());
69
70auto f2a(int n) { return n; }
71decltype(auto) f2d(int n) { return n; }
72using Int = decltype(f2a(0));
73using Int = decltype(f2d(0));
74
75auto f3a(int n) { return (n); }
76decltype(auto) f3d(int n) { return (n); } // expected-warning {{reference to stack memory}}
77using Int = decltype(f3a(0));
78using IntLRef = decltype(f3d(0));
79
80auto f4a(int n) { return f(); }
81decltype(auto) f4d(int n) { return f(); }
82using Int = decltype(f4a(0));
83using IntRRef = decltype(f4d(0));
84
85auto f5aa(int n) { auto x = f(); return x; }
86auto f5ad(int n) { decltype(auto) x = f(); return x; }
87decltype(auto) f5da(int n) { auto x = f(); return x; }
88decltype(auto) f5dd(int n) { decltype(auto) x = f(); return x; } // expected-error {{rvalue reference to type 'int' cannot bind to lvalue}}
89using Int = decltype(f5aa(0));
90using Int = decltype(f5ad(0));
91using Int = decltype(f5da(0));
92
93auto init_list_1() { return { 1, 2, 3 }; } // expected-error {{cannot deduce return type from initializer list}}
94decltype(auto) init_list_2() { return { 1, 2, 3 }; } // expected-error {{cannot deduce return type from initializer list}}
95