msg_329.c revision 1.4 
1/*	$NetBSD: msg_329.c,v 1.4 2022/06/17 06:59:16 rillig Exp $	*/
2# 3 "msg_329.c"
3
4// Test for message: type '%s' is not a member of '%s' [329]
5
6union u {
7	int i1;
8	int i2;
9	void *vp;
10};
11
12void
13example(void)
14{
15	/*
16	 * A type cast to a union type is valid if the source type is any
17	 * member type of the union.  Since all union members with the same
18	 * type have the same representation, the name of the union member
19	 * doesn't matter.
20	 *
21	 * XXX: could there be padding bits or other tricky details that are
22	 * settable per-member?  These could make the type alone insufficient
23	 * for determining the exact representation.
24	 *
25	 * C99 6.5.4 "Cast operators" does not mention a union cast.  On the
26	 * contrary, it says that the type name shall specify a scalar type.
27	 *
28	 * C11 6.5.4 "Cast operators" differs from C99 but still requires
29	 * scalar types for both the target type and the source value.
30	 *
31	 * This is a GCC extension.
32	 * See https://gcc.gnu.org/onlinedocs/gcc/Cast-to-Union.html.
33	 */
34	union u u_i1 = (union u)3;
35	union u u_vp = (union u)(void *)0;
36	/* expect+1: error: type 'pointer to char' is not a member of 'union u' [329] */
37	union u u_cp = (union u)(char *)0;
38}
39