lint: accept _Complex type specifiers in any order

C23 6.7.3.1p2 says so.

Seen in external/gpl3/gcc/dist/libquadmath/quadmath.h:33.

Author: rillig

tests/usr.bin/xlint/lint1/msg_308.c

@@ -1,4 +1,4 @@
-/*	$NetBSD: msg_308.c,v 1.9 2025/04/12 15:49:50 rillig Exp $	*/
+/*	$NetBSD: msg_308.c,v 1.10 2026/01/20 23:33:05 rillig Exp $	*/
 # 3 "msg_308.c"
 
 // Test for message: invalid type for _Complex [308]
@@ -15,3 +15,30 @@ _Complex plain_complex;
 /* expect+2: error: invalid type for _Complex [308] */
 /* expect+1: error: invalid type combination [4] */
 int _Complex int_complex;
+
+void *ptr;
+
+void
+reveal_types(void)
+{
+	/* expect+1: ... 'float _Complex' [171] */
+	ptr = (_Complex float)0.0;
+	/* expect+1: ... 'float _Complex' [171] */
+	ptr = (float _Complex)0.0;
+	/* expect+1: ... 'double _Complex' [171] */
+	ptr = (_Complex double)0.0;
+	/* expect+1: ... 'double _Complex' [171] */
+	ptr = (double _Complex)0.0;
+	/* expect+1: ... 'long double _Complex' [171] */
+	ptr = (_Complex double long)0.0;
+	/* expect+1: ... 'long double _Complex' [171] */
+	ptr = (_Complex long double)0.0;
+	/* expect+1: ... 'long double _Complex' [171] */
+	ptr = (double _Complex long)0.0;
+	/* expect+1: ... 'long double _Complex' [171] */
+	ptr = (double long _Complex)0.0;
+	/* expect+1: ... 'long double _Complex' [171] */
+	ptr = (long _Complex double)0.0;
+	/* expect+1: ... 'long double _Complex' [171] */
+	ptr = (long double _Complex)0.0;
+}

usr.bin/xlint/lint1/decl.c

@@ -1,4 +1,4 @@
-/* $NetBSD: decl.c,v 1.423 2026/01/17 14:27:08 rillig Exp $ */
+/* $NetBSD: decl.c,v 1.424 2026/01/20 23:33:05 rillig Exp $ */
 
 /*
  * Copyright (c) 1996 Christopher G. Demetriou.  All Rights Reserved.
@@ -38,7 +38,7 @@
 
 #include <sys/cdefs.h>
 #if defined(__RCSID)
-__RCSID("$NetBSD: decl.c,v 1.423 2026/01/17 14:27:08 rillig Exp $");
+__RCSID("$NetBSD: decl.c,v 1.424 2026/01/20 23:33:05 rillig Exp $");
 #endif
 
 #include <sys/param.h>
@@ -352,11 +352,8 @@ dcs_add_type(type_t *tp)
 			t = FCOMPLEX;
 		else if (dcs->d_complex_mod == DOUBLE)
 			t = DCOMPLEX;
-		else {
-			/* invalid type for _Complex */
-			error(308);
-			t = DCOMPLEX;	/* just as a fallback */
-		}
+		else if (dcs->d_abstract_type == NO_TSPEC)
+			t = COMPLEX;
 		dcs->d_complex_mod = NO_TSPEC;
 	}
 
@@ -395,9 +392,11 @@ dcs_add_type(type_t *tp)
 				dcs->d_invalid_type_combination = true;
 			dcs->d_abstract_type = t;
 		}
-	} else if (t == PTR) {
+	} else if (t == PTR)
 		dcs->d_type = tp;
-	} else {
+	else if (t == COMPLEX && dcs->d_abstract_type == NO_TSPEC)
+		dcs->d_abstract_type = t;
+	else {
 		if (dcs->d_abstract_type != NO_TSPEC)
 			dcs->d_invalid_type_combination = true;
 		dcs->d_abstract_type = t;
@@ -723,6 +722,17 @@ dcs_merge_declaration_specifiers(void)
 	if (t == LDOUBLE && !allow_c90)
 		/* 'long double' requires C90 or later */
 		warning(266);
+	if (t == COMPLEX && c == FLOAT)
+		t = FCOMPLEX;
+	else if (t == COMPLEX && c == DOUBLE)
+		t = DCOMPLEX;
+	else if (t == COMPLEX && c == LDOUBLE)
+		t = LCOMPLEX;
+	else if (t == COMPLEX) {
+		/* invalid type for _Complex */
+		error(308);
+		t = DCOMPLEX;
+	}
 	if (l == LONG && t == DCOMPLEX) {
 		l = NO_TSPEC;
 		t = LCOMPLEX;