msg_161.c revision 1.12 
1/*	$NetBSD: msg_161.c,v 1.12 2024/11/13 04:32:49 rillig Exp $	*/
2# 3 "msg_161.c"
3
4// Test for message: constant in conditional context [161]
5
6/* lint1-extra-flags: -h -X 351 */
7
8void
9while_1(void)
10{
11	/* expect+1: warning: constant in conditional context [161] */
12	while (1)
13		continue;
14}
15
16void
17while_0(void)
18{
19	/* expect+1: warning: constant in conditional context [161] */
20	while (0) {
21		/* expect+1: warning: 'continue' statement not reached [193] */
22		continue;
23	}
24}
25
26/*
27 * The pattern 'do { } while (0)' is a common technique to define a
28 * preprocessor macro that behaves like a single statement.  There is
29 * nothing unusual or surprising about the constant condition.
30 * Before tree.c 1.202 from 2021-01-31, lint warned about it.
31 */
32void
33do_while_0(void)
34{
35	do {
36
37	} while (0);
38}
39
40void
41do_while_1(void)
42{
43	do {
44		/* expect+1: warning: constant in conditional context [161] */
45	} while (1);
46}
47
48extern void println(const char *);
49
50/*
51 * Since 2021-02-28, lint no longer warns about constant controlling
52 * expressions involving sizeof since these are completely legitimate.
53 */
54void
55test_sizeof(void)
56{
57	if (sizeof(int) > sizeof(char))
58		println("very probable");
59	if (sizeof(int) < sizeof(char))
60		println("impossible");
61}
62
63const _Bool conditions[] = {
64	/* XXX: Why no warning here? */
65	13 < 13,
66	/* XXX: Why no warning here? */
67	0 < 0,
68	/* XXX: Why no warning here? */
69	0 != 0,
70	/* expect+1: warning: constant in conditional context [161] */
71	0 == 0 && 1 == 0,
72	/* expect+1: warning: constant in conditional context [161] */
73	1 == 0 || 2 == 1,
74	/* expect+2: warning: constant in conditional context [161] */
75	/* expect+1: error: non-constant initializer [177] */
76	0 == 0 && ""[0] == '\0',
77	/* expect+2: warning: constant in conditional context [161] */
78	/* expect+1: error: non-constant initializer [177] */
79	""[0] == '\0' && 0 == 0,
80	/* C99 6.6p3: Constant expressions shall not contain [...] comma */
81	/* expect+2: warning: expression has null effect [129] */
82	/* expect+1: error: non-constant initializer [177] */
83	(0 == 0, 1 == 0),
84};
85