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* [Bug c/66341] New: Some casts wrongly produce a lvalue
@ 2015-05-30 8:24 kp.lehrmann+gcc at gmail dot com
2015-05-30 16:31 ` [Bug c/66341] " msebor at gcc dot gnu.org
` (4 more replies)
0 siblings, 5 replies; 6+ messages in thread
From: kp.lehrmann+gcc at gmail dot com @ 2015-05-30 8:24 UTC (permalink / raw)
To: gcc-bugs
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=66341
Bug ID: 66341
Summary: Some casts wrongly produce a lvalue
Product: gcc
Version: 5.1.0
Status: UNCONFIRMED
Severity: minor
Priority: P3
Component: c
Assignee: unassigned at gcc dot gnu.org
Reporter: kp.lehrmann+gcc at gmail dot com
Target Milestone: ---
Created attachment 35653
--> https://gcc.gnu.org/bugzilla/attachment.cgi?id=35653&action=edit
gcc compiles ok instead of producing a "error: lvalue required as left operand
of assignment"
Hello,
gcc (any version that I tried) allows some casts to produce a lvalue, whereas
"error: lvalue required as left operand of assignment" would be expected.
Basically, cast of the following form wrongly compile:
struct B{ int *c;};
struct A{ struct B b;};
struct A a;
int d = 5;
(int*)((struct A *)(&a)->b.c) = &d;
Note that if the first cast (int*) is replaced by a cast to any type but the
type of the member in struct B, the expected error message is produced.
For instance,
(char*)((struct A *)(&a)->b.c) = &d;
produce the expected error.
Best regards
^ permalink raw reply [flat|nested] 6+ messages in thread* [Bug c/66341] Some casts wrongly produce a lvalue 2015-05-30 8:24 [Bug c/66341] New: Some casts wrongly produce a lvalue kp.lehrmann+gcc at gmail dot com @ 2015-05-30 16:31 ` msebor at gcc dot gnu.org 2015-06-03 16:20 ` mpolacek at gcc dot gnu.org ` (3 subsequent siblings) 4 siblings, 0 replies; 6+ messages in thread From: msebor at gcc dot gnu.org @ 2015-05-30 16:31 UTC (permalink / raw) To: gcc-bugs https://gcc.gnu.org/bugzilla/show_bug.cgi?id=66341 Martin Sebor <msebor at gcc dot gnu.org> changed: What |Removed |Added ---------------------------------------------------------------------------- Status|UNCONFIRMED |NEW Last reconfirmed| |2015-05-30 CC| |msebor at gcc dot gnu.org Ever confirmed|0 |1 --- Comment #1 from Martin Sebor <msebor at gcc dot gnu.org> --- Confirmed with both gcc and g++ 5.1.0. Below is a slightly smaller test case along with Clang output. $ cat t.c && gcc -Wall -c t.c && clang t.c struct A { int *i; }; void foo (struct A *a) { (int*)(struct A*)a->i = a->i; } t.c:5:27: error: expression is not assignable (int*)(struct A*)a->i = a->i; ~~~~~~~~~~~~~~~~~~~~~ ^ 1 error generated. ^ permalink raw reply [flat|nested] 6+ messages in thread
* [Bug c/66341] Some casts wrongly produce a lvalue 2015-05-30 8:24 [Bug c/66341] New: Some casts wrongly produce a lvalue kp.lehrmann+gcc at gmail dot com 2015-05-30 16:31 ` [Bug c/66341] " msebor at gcc dot gnu.org @ 2015-06-03 16:20 ` mpolacek at gcc dot gnu.org 2015-06-04 8:18 ` mpolacek at gcc dot gnu.org ` (2 subsequent siblings) 4 siblings, 0 replies; 6+ messages in thread From: mpolacek at gcc dot gnu.org @ 2015-06-03 16:20 UTC (permalink / raw) To: gcc-bugs https://gcc.gnu.org/bugzilla/show_bug.cgi?id=66341 Marek Polacek <mpolacek at gcc dot gnu.org> changed: What |Removed |Added ---------------------------------------------------------------------------- Status|NEW |ASSIGNED CC| |mpolacek at gcc dot gnu.org Assignee|unassigned at gcc dot gnu.org |mpolacek at gcc dot gnu.org ^ permalink raw reply [flat|nested] 6+ messages in thread
* [Bug c/66341] Some casts wrongly produce a lvalue 2015-05-30 8:24 [Bug c/66341] New: Some casts wrongly produce a lvalue kp.lehrmann+gcc at gmail dot com 2015-05-30 16:31 ` [Bug c/66341] " msebor at gcc dot gnu.org 2015-06-03 16:20 ` mpolacek at gcc dot gnu.org @ 2015-06-04 8:18 ` mpolacek at gcc dot gnu.org 2015-06-04 8:18 ` mpolacek at gcc dot gnu.org 2023-03-23 1:23 ` pinskia at gcc dot gnu.org 4 siblings, 0 replies; 6+ messages in thread From: mpolacek at gcc dot gnu.org @ 2015-06-04 8:18 UTC (permalink / raw) To: gcc-bugs https://gcc.gnu.org/bugzilla/show_bug.cgi?id=66341 --- Comment #2 from Marek Polacek <mpolacek at gcc dot gnu.org> --- Author: mpolacek Date: Thu Jun 4 08:17:45 2015 New Revision: 224115 URL: https://gcc.gnu.org/viewcvs?rev=224115&root=gcc&view=rev Log: PR c/66341 * c-typeck.c (build_c_cast): Wrap VALUE into NON_LVALUE_EXPR if it is a lvalue. * gcc.dg/lvalue-8.c: New test. Added: trunk/gcc/testsuite/gcc.dg/lvalue-8.c Modified: trunk/gcc/c/ChangeLog trunk/gcc/c/c-typeck.c trunk/gcc/testsuite/ChangeLog ^ permalink raw reply [flat|nested] 6+ messages in thread
* [Bug c/66341] Some casts wrongly produce a lvalue 2015-05-30 8:24 [Bug c/66341] New: Some casts wrongly produce a lvalue kp.lehrmann+gcc at gmail dot com ` (2 preceding siblings ...) 2015-06-04 8:18 ` mpolacek at gcc dot gnu.org @ 2015-06-04 8:18 ` mpolacek at gcc dot gnu.org 2023-03-23 1:23 ` pinskia at gcc dot gnu.org 4 siblings, 0 replies; 6+ messages in thread From: mpolacek at gcc dot gnu.org @ 2015-06-04 8:18 UTC (permalink / raw) To: gcc-bugs https://gcc.gnu.org/bugzilla/show_bug.cgi?id=66341 Marek Polacek <mpolacek at gcc dot gnu.org> changed: What |Removed |Added ---------------------------------------------------------------------------- Status|ASSIGNED |RESOLVED Resolution|--- |FIXED --- Comment #3 from Marek Polacek <mpolacek at gcc dot gnu.org> --- Fixed. ^ permalink raw reply [flat|nested] 6+ messages in thread
* [Bug c/66341] Some casts wrongly produce a lvalue 2015-05-30 8:24 [Bug c/66341] New: Some casts wrongly produce a lvalue kp.lehrmann+gcc at gmail dot com ` (3 preceding siblings ...) 2015-06-04 8:18 ` mpolacek at gcc dot gnu.org @ 2023-03-23 1:23 ` pinskia at gcc dot gnu.org 4 siblings, 0 replies; 6+ messages in thread From: pinskia at gcc dot gnu.org @ 2023-03-23 1:23 UTC (permalink / raw) To: gcc-bugs https://gcc.gnu.org/bugzilla/show_bug.cgi?id=66341 Andrew Pinski <pinskia at gcc dot gnu.org> changed: What |Removed |Added ---------------------------------------------------------------------------- Target Milestone|--- |6.0 ^ permalink raw reply [flat|nested] 6+ messages in thread
end of thread, other threads:[~2023-03-23 1:23 UTC | newest] Thread overview: 6+ messages (download: mbox.gz / follow: Atom feed) -- links below jump to the message on this page -- 2015-05-30 8:24 [Bug c/66341] New: Some casts wrongly produce a lvalue kp.lehrmann+gcc at gmail dot com 2015-05-30 16:31 ` [Bug c/66341] " msebor at gcc dot gnu.org 2015-06-03 16:20 ` mpolacek at gcc dot gnu.org 2015-06-04 8:18 ` mpolacek at gcc dot gnu.org 2015-06-04 8:18 ` mpolacek at gcc dot gnu.org 2023-03-23 1:23 ` pinskia at gcc dot gnu.org
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