[src/trunk]: src/usr.bin/xlint/lint1 lint: remove support for obsolete GCC-st...

[rillig <rillig%NetBSD.org@localhost>]

details:   https://anonhg.NetBSD.org/src/rev/f343c10f6c7e
branches:  trunk
changeset: 1022100:f343c10f6c7e
user:      rillig <rillig%NetBSD.org@localhost>
date:      Sun Jul 04 12:24:38 2021 +0000

description:
lint: remove support for obsolete GCC-style lvalue casts

Since GCC 4.0, a cast results in an rvalue.

diffstat:

 tests/usr.bin/xlint/lint1/msg_163.c   |  20 +++++++++++++++++---
 tests/usr.bin/xlint/lint1/msg_163.exp |   6 ++++--
 usr.bin/xlint/lint1/tree.c            |   6 ++----
 3 files changed, 23 insertions(+), 9 deletions(-)

diffs (70 lines):

diff -r 9733b8e9d493 -r f343c10f6c7e tests/usr.bin/xlint/lint1/msg_163.c
--- a/tests/usr.bin/xlint/lint1/msg_163.c       Sun Jul 04 11:25:07 2021 +0000
+++ b/tests/usr.bin/xlint/lint1/msg_163.c       Sun Jul 04 12:24:38 2021 +0000
@@ -1,4 +1,4 @@
-/*     $NetBSD: msg_163.c,v 1.3 2021/04/05 01:35:34 rillig Exp $       */
+/*     $NetBSD: msg_163.c,v 1.4 2021/07/04 12:24:39 rillig Exp $       */
 # 3 "msg_163.c"
 
 // Test for message: a cast does not yield an lvalue [163]
@@ -7,7 +7,21 @@
 example(char *p, int i)
 {
        p++;
-       ((char *)p)++;          /* XXX: why is this ok? */
+
+       /*
+        * Using a cast as an lvalue had been a GCC extension until 3.4.
+        * It was removed in GCC 4.0.
+        *
+        * https://gcc.gnu.org/onlinedocs/gcc-3.4.6/gcc/Lvalues.html#Lvalues
+        * https://gcc.gnu.org/onlinedocs/gcc-4.0.4/gcc/index.html#toc_C-Extensions
+        */
+       /* expect+2: error: a cast does not yield an lvalue [163] */
+       /* expect+1: error: operand of 'x++' must be lvalue [114] */
+       ((char *)p)++;
+
        i++;
-       ((int)i)++;             /* expect: 163 *//* expect: 114 */
+
+       /* expect+2: error: a cast does not yield an lvalue [163] */
+       /* expect+1: error: operand of 'x++' must be lvalue [114] */
+       ((int)i)++;
 }
diff -r 9733b8e9d493 -r f343c10f6c7e tests/usr.bin/xlint/lint1/msg_163.exp
--- a/tests/usr.bin/xlint/lint1/msg_163.exp     Sun Jul 04 11:25:07 2021 +0000
+++ b/tests/usr.bin/xlint/lint1/msg_163.exp     Sun Jul 04 12:24:38 2021 +0000
@@ -1,2 +1,4 @@
-msg_163.c(12): error: a cast does not yield an lvalue [163]
-msg_163.c(12): error: operand of 'x++' must be lvalue [114]
+msg_163.c(20): error: a cast does not yield an lvalue [163]
+msg_163.c(20): error: operand of 'x++' must be lvalue [114]
+msg_163.c(26): error: a cast does not yield an lvalue [163]
+msg_163.c(26): error: operand of 'x++' must be lvalue [114]
diff -r 9733b8e9d493 -r f343c10f6c7e usr.bin/xlint/lint1/tree.c
--- a/usr.bin/xlint/lint1/tree.c        Sun Jul 04 11:25:07 2021 +0000
+++ b/usr.bin/xlint/lint1/tree.c        Sun Jul 04 12:24:38 2021 +0000
@@ -1,4 +1,4 @@
-/*     $NetBSD: tree.c,v 1.306 2021/07/04 09:13:59 rillig Exp $        */
+/*     $NetBSD: tree.c,v 1.307 2021/07/04 12:24:38 rillig Exp $        */
 
 /*
  * Copyright (c) 1994, 1995 Jochen Pohl
@@ -37,7 +37,7 @@
 
 #include <sys/cdefs.h>
 #if defined(__RCSID) && !defined(lint)
-__RCSID("$NetBSD: tree.c,v 1.306 2021/07/04 09:13:59 rillig Exp $");
+__RCSID("$NetBSD: tree.c,v 1.307 2021/07/04 12:24:38 rillig Exp $");
 #endif
 
 #include <float.h>
@@ -760,8 +760,6 @@
        if (!tn->tn_lvalue) {
                if (tn->tn_op == CVT && tn->tn_cast &&
                    tn->tn_left->tn_op == LOAD) {
-                       if (tn->tn_type->t_tspec == PTR)
-                               return true;
                        /* a cast does not yield an lvalue */
                        error(163);
                }