1// RUN: %clang_cc1 -Wreturn-type -fsyntax-only -std=c++11 -verify %s
2
3class A {
4public:
5  A(const A&);
6};
7
8struct S {
9  int i;
10  double d;
11
12  virtual void B() {}
13};
14
15union U {
16  struct {
17    int i;
18    virtual void B() {} // Can only do this in C++11
19  } t;
20};
21
22struct S2 {
23  int i;
24  double d;
25};
26
27extern "C" U f3( void ); // expected-warning {{'f3' has C-linkage specified, but returns user-defined type 'U' which is incompatible with C}}
28extern "C" S f0(void); // expected-warning {{'f0' has C-linkage specified, but returns user-defined type 'S' which is incompatible with C}}
29extern "C" A f4( void ); // expected-warning {{'f4' has C-linkage specified, but returns user-defined type 'A' which is incompatible with C}}
30
31// These should all be fine
32extern "C" S2 f5( void );
33extern "C" void f2( A x );
34extern "C" void f6( S s );
35extern "C" void f7( U u );
36extern "C" double f8(void);
37extern "C" long long f11( void );
38extern "C" A *f10( void );
39
40extern "C" struct mypodstruct f12(); // expected-warning {{'f12' has C-linkage specified, but returns incomplete type 'struct mypodstruct' which could be incompatible with C}}
41
42namespace test2 {
43  // FIXME: we should probably suppress the first warning as the second one
44  // is more precise.
45  // For now this tests that a second 'extern "C"' is not necessary to trigger
46  // the warning.
47  struct A;
48  extern "C" A f(void); // expected-warning {{'f' has C-linkage specified, but returns incomplete type 'test2::A' which could be incompatible with C}}
49  struct A {
50    A(const A&);
51  };
52  A f(void);  // no warning. warning is already issued on first declaration.
53}
54
55namespace test3 {
56  struct A {
57    A(const A&);
58  };
59  extern "C" {
60    // Don't warn for static functions.
61    static A f(void);
62  }
63}
64
65// rdar://13364028
66namespace rdar13364028 {
67class A {
68public:
69    virtual int x();
70};
71
72extern "C" {
73#pragma clang diagnostic push
74#pragma clang diagnostic ignored "-Wreturn-type-c-linkage"
75A xyzzy();
76#pragma clang diagnostic pop
77A bbb(); // expected-warning {{'bbb' has C-linkage specified, but returns user-defined type 'rdar13364028::A' which is incompatible with C}}
78A ccc() { // expected-warning {{'ccc' has C-linkage specified, but returns user-defined type 'rdar13364028::A' which is incompatible with C}}
79  return A();
80};
81}
82
83A xyzzy();
84
85A xyzzy()
86{
87  return A();
88}
89
90A bbb()
91{
92  return A();
93}
94
95A bbb();
96
97A ccc();
98}
99