1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
|
// RUN: %clang_cc1 -verify=expected,c-expected -std=c2y -Wall -pedantic %s
// RUN: %clang_cc1 -verify=expected,c-expected,ped -std=c23 -Wall -pedantic %s
// RUN: %clang_cc1 -verify=expected,cxx-expected,gnu -Wall -pedantic -x c++ %s
// RUN: %clang_cc1 -verify=expected,c-expected,pre -std=c2y -Wpre-c2y-compat -Wall -pedantic %s
/* WG14 N3370: Yes
* Case range expressions v3.1
*
* This introduces the ability to specify closed ranges in case statements in a
* switch statement. This was already a well-supported Clang extension before
* it was standardized.
*/
void correct(int i) {
constexpr int j = 100, k = 200;
switch (i) {
case 12 ... 14: break; /* gnu-warning {{case ranges are a GNU extension}}
ped-warning {{case ranges are a C2y extension}}
pre-warning {{case ranges are incompatible with C standards before C2y}}
*/
// Implementations are encouraged to diagnose empty ranges.
case 15 ... 11: break; /* expected-warning {{empty case range specified}}
gnu-warning {{case ranges are a GNU extension}}
ped-warning {{case ranges are a C2y extension}}
pre-warning {{case ranges are incompatible with C standards before C2y}}
*/
// This is not an empty range, it's a range of a single value.
case 10 ... 10: break; /* gnu-warning {{case ranges are a GNU extension}}
ped-warning {{case ranges are a C2y extension}}
pre-warning {{case ranges are incompatible with C standards before C2y}}
*/
case j ... k: break; /* gnu-warning {{case ranges are a GNU extension}}
ped-warning {{case ranges are a C2y extension}}
pre-warning {{case ranges are incompatible with C standards before C2y}}
*/
}
}
void incorrect(int i) { // cxx-expected-note 2 {{declared here}}
switch (i) {
// The values have to be integer constant expressions. Note that when the
// initial value in the range is an error, we don't issue the warnings about
// extensions or incompatibility.
case i ... 10: break; /* c-expected-error {{expression is not an integer constant expression}}
cxx-expected-error {{case value is not a constant expression}}
cxx-expected-note {{function parameter 'i' with unknown value cannot be used in a constant expression}}
*/
case 10 ... i: break; /* c-expected-error {{expression is not an integer constant expression}}
cxx-expected-error {{case value is not a constant expression}}
cxx-expected-note {{function parameter 'i' with unknown value cannot be used in a constant expression}}
gnu-warning {{case ranges are a GNU extension}}
ped-warning {{case ranges are a C2y extension}}
pre-warning {{case ranges are incompatible with C standards before C2y}}
*/
case 1.3f ... 10: break; /* c-expected-error {{integer constant expression must have integer type, not 'float'}}
cxx-expected-error {{conversion from 'float' to 'int' is not allowed in a converted constant expression}}
*/
case 10 ... "a": break; /* c-expected-error {{integer constant expression must have integer type, not 'char[2]'}}
cxx-expected-error {{value of type 'const char[2]' is not implicitly convertible to 'int'}}
gnu-warning {{case ranges are a GNU extension}}
ped-warning {{case ranges are a C2y extension}}
pre-warning {{case ranges are incompatible with C standards before C2y}}
*/
}
switch (i) {
// Cannot have multiple cases covering the same value.
// FIXME: diagnostic quality here is poor. The "previous case" note is
// showing up on a subsequent line (I'd expect the error and note to be
// reversed), and "duplicate case value 20" is showing up on a line where
// there is no duplicate value 20 to begin with.
case 10 ... 20: break; /* expected-error {{duplicate case value '11'}}
expected-note {{previous case defined here}}
gnu-warning {{case ranges are a GNU extension}}
ped-warning {{case ranges are a C2y extension}}
pre-warning {{case ranges are incompatible with C standards before C2y}}
*/
case 11: break; /* expected-note {{previous case defined here}}
*/
case 11 ... 14: break; /* expected-error {{duplicate case value '20'}}
gnu-warning {{case ranges are a GNU extension}}
ped-warning {{case ranges are a C2y extension}}
pre-warning {{case ranges are incompatible with C standards before C2y}}
*/
}
// The values specified by the range shall not change as a result of
// conversion to the promoted type of the controlling expression.
// FIXME: the overflow warnings seem like they probably should also trigger
// in C++ as they do in C.
switch ((unsigned char)i) {
case 254 ... 256: break; /* c-expected-warning {{overflow converting case value to switch condition type (256 to 0)}}
gnu-warning {{case ranges are a GNU extension}}
ped-warning {{case ranges are a C2y extension}}
pre-warning {{case ranges are incompatible with C standards before C2y}}
*/
case 257 ... 258: break; /* c-expected-warning {{overflow converting case value to switch condition type (257 to 1)}}
c-expected-warning {{overflow converting case value to switch condition type (258 to 2)}}
gnu-warning {{case ranges are a GNU extension}}
ped-warning {{case ranges are a C2y extension}}
pre-warning {{case ranges are incompatible with C standards before C2y}}
*/
}
}
|
