1 // RUN: %clang_cc1 -Wreturn-type -fsyntax-only -std=c++11 -verify %s
2
3 class A {
4 public:
5 A(const A&);
6 };
7
8 struct S {
9 int i;
10 double d;
11
BS12 virtual void B() {}
13 };
14
15 union U {
16 struct {
17 int i;
BU::__anoneec446db010818 virtual void B() {} // Can only do this in C++11
19 } t;
20 };
21
22 struct S2 {
23 int i;
24 double d;
25 };
26
27 extern "C" U f3( void ); // expected-warning {{'f3' has C-linkage specified, but returns user-defined type 'U' which is incompatible with C}}
28 extern "C" S f0(void); // expected-warning {{'f0' has C-linkage specified, but returns user-defined type 'S' which is incompatible with C}}
29 extern "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
32 extern "C" S2 f5( void );
33 extern "C" void f2( A x );
34 extern "C" void f6( S s );
35 extern "C" void f7( U u );
36 extern "C" double f8(void);
37 extern "C" long long f11( void );
38 extern "C" A *f10( void );
39
40 extern "C" struct mypodstruct f12(); // expected-warning {{'f12' has C-linkage specified, but returns incomplete type 'struct mypodstruct' which could be incompatible with C}}
41
42 namespace 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
55 namespace 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
66 namespace rdar13364028 {
67 class A {
68 public:
69 virtual int x();
70 };
71
72 extern "C" {
73 #pragma clang diagnostic push
74 #pragma clang diagnostic ignored "-Wreturn-type-c-linkage"
75 A xyzzy();
76 #pragma clang diagnostic pop
77 A bbb(); // expected-warning {{'bbb' has C-linkage specified, but returns user-defined type 'rdar13364028::A' which is incompatible with C}}
ccc()78 A 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
83 A xyzzy();
84
xyzzy()85 A xyzzy()
86 {
87 return A();
88 }
89
bbb()90 A bbb()
91 {
92 return A();
93 }
94
95 A bbb();
96
97 A ccc();
98 }
99