1 // RUN: %clang_cc1 -fsyntax-only -verify -std=c++11 -Wimplicit-fallthrough -DCOMMAND_LINE_FALLTHROUGH=[[clang::fallthrough]] %s
2 
fallthrough_compatibility_macro_from_command_line(int n)3 int fallthrough_compatibility_macro_from_command_line(int n) {
4   switch (n) {
5     case 0:
6       n = n * 10;
7     case 1: // expected-warning{{unannotated fall-through between switch labels}} expected-note{{insert 'COMMAND_LINE_FALLTHROUGH;' to silence this warning}} expected-note{{insert 'break;' to avoid fall-through}}
8       ;
9   }
10   return n;
11 }
12 
13 #ifdef __clang__
14 #if __has_feature(cxx_attributes) && __has_warning("-Wimplicit-fallthrough")
15 #define COMPATIBILITY_FALLTHROUGH   [ [ /* test */  clang /* test */ \
16     ::  fallthrough  ]  ]    // testing whitespace and comments in macro definition
17 #endif
18 #endif
19 
20 #ifndef COMPATIBILITY_FALLTHROUGH
21 #define COMPATIBILITY_FALLTHROUGH do { } while (0)
22 #endif
23 
fallthrough_compatibility_macro_from_source(int n)24 int fallthrough_compatibility_macro_from_source(int n) {
25   switch (n) {
26     case 0:
27       n = n * 20;
28     case 1: // expected-warning{{unannotated fall-through between switch labels}} expected-note{{insert 'COMPATIBILITY_FALLTHROUGH;' to silence this warning}} expected-note{{insert 'break;' to avoid fall-through}}
29       ;
30   }
31   return n;
32 }
33 
34 // Deeper macro substitution
35 #define M1 [[clang::fallthrough]]
36 #ifdef __clang__
37 #define M2 M1
38 #else
39 #define M2
40 #endif
41 
42 #define WRONG_MACRO1 clang::fallthrough
43 #define WRONG_MACRO2 [[clang::fallthrough]
44 #define WRONG_MACRO3 [[clang::fall through]]
45 #define WRONG_MACRO4 [[clang::fallthrough]]]
46 
fallthrough_compatibility_macro_in_macro(int n)47 int fallthrough_compatibility_macro_in_macro(int n) {
48   switch (n) {
49     case 0:
50       n = n * 20;
51     case 1: // expected-warning{{unannotated fall-through between switch labels}} expected-note{{insert 'M1;' to silence this warning}} expected-note{{insert 'break;' to avoid fall-through}}
52                                                                           // there was an idea that this ^ should be M2
53       ;
54   }
55   return n;
56 }
57 
58 #undef M1
59 #undef M2
60 #undef COMPATIBILITY_FALLTHROUGH
61 #undef COMMAND_LINE_FALLTHROUGH
62 
fallthrough_compatibility_macro_undefined(int n)63 int fallthrough_compatibility_macro_undefined(int n) {
64   switch (n) {
65     case 0:
66       n = n * 20;
67     case 1: // expected-warning{{unannotated fall-through between switch labels}} expected-note{{insert '[[clang::fallthrough]];' to silence this warning}} expected-note{{insert 'break;' to avoid fall-through}}
68       ;
69   }
70 #define TOO_LATE [[clang::fallthrough]]
71   return n;
72 }
73 #undef TOO_LATE
74 
75 #define MACRO_WITH_HISTORY 11111111
76 #undef MACRO_WITH_HISTORY
77 #define MACRO_WITH_HISTORY [[clang::fallthrough]]
78 #undef MACRO_WITH_HISTORY
79 #define MACRO_WITH_HISTORY 2222222
80 
fallthrough_compatibility_macro_history(int n)81 int fallthrough_compatibility_macro_history(int n) {
82   switch (n) {
83     case 0:
84       n = n * 20;
85 #undef MACRO_WITH_HISTORY
86     case 1: // expected-warning{{unannotated fall-through between switch labels}} expected-note{{insert '[[clang::fallthrough]];' to silence this warning}} expected-note{{insert 'break;' to avoid fall-through}}
87       ;
88 #define MACRO_WITH_HISTORY [[clang::fallthrough]]
89   }
90   return n;
91 }
92 
93 #undef MACRO_WITH_HISTORY
94 #define MACRO_WITH_HISTORY 11111111
95 #undef MACRO_WITH_HISTORY
96 #define MACRO_WITH_HISTORY [[clang::fallthrough]]
97 #undef MACRO_WITH_HISTORY
98 #define MACRO_WITH_HISTORY 2222222
99 #undef MACRO_WITH_HISTORY
100 
fallthrough_compatibility_macro_history2(int n)101 int fallthrough_compatibility_macro_history2(int n) {
102   switch (n) {
103     case 0:
104       n = n * 20;
105 #define MACRO_WITH_HISTORY [[clang::fallthrough]]
106     case 1: // expected-warning{{unannotated fall-through between switch labels}} expected-note{{insert 'MACRO_WITH_HISTORY;' to silence this warning}} expected-note{{insert 'break;' to avoid fall-through}}
107       ;
108 #undef MACRO_WITH_HISTORY
109 #define MACRO_WITH_HISTORY 3333333
110 #undef MACRO_WITH_HISTORY
111 #define MACRO_WITH_HISTORY 4444444
112 #undef MACRO_WITH_HISTORY
113 #define MACRO_WITH_HISTORY 5555555
114   }
115   return n;
116 }
117 
118 template<const int N>
fallthrough_compatibility_macro_history_template(int n)119 int fallthrough_compatibility_macro_history_template(int n) {
120   switch (N * n) {
121     case 0:
122       n = n * 20;
123 #define MACRO_WITH_HISTORY2 [[clang::fallthrough]]
124     case 1: // expected-warning{{unannotated fall-through between switch labels}} expected-note{{insert 'MACRO_WITH_HISTORY2;' to silence this warning}} expected-note{{insert 'break;' to avoid fall-through}}
125       ;
126 #undef MACRO_WITH_HISTORY2
127 #define MACRO_WITH_HISTORY2 3333333
128   }
129   return n;
130 }
131 
132 #undef MACRO_WITH_HISTORY2
133 #define MACRO_WITH_HISTORY2 4444444
134 #undef MACRO_WITH_HISTORY2
135 #define MACRO_WITH_HISTORY2 5555555
136 
f()137 void f() {
138   fallthrough_compatibility_macro_history_template<1>(0); // expected-note{{in instantiation of function template specialization 'fallthrough_compatibility_macro_history_template<1>' requested here}}
139 }
140