[Bug c/99972] missing -Wunused-result on a call to a locally redeclared warn_unused_result function

2021-04-15 Thread msebor at gcc dot gnu.org via Gcc-bugs 
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=99972

Martin Sebor  changed:

   What|Removed |Added

   Target Milestone|--- |11.0
 Resolution|--- |FIXED
 Status|ASSIGNED|RESOLVED

--- Comment #5 from Martin Sebor  ---
Fix committed in r11-8205.

[Bug c/99972] missing -Wunused-result on a call to a locally redeclared warn_unused_result function

2021-04-15 Thread cvs-commit at gcc dot gnu.org via Gcc-bugs 
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=99972

--- Comment #4 from CVS Commits  ---
The master branch has been updated by Martin Sebor :

https://gcc.gnu.org/g:da879e01ecd35737c18be1da3324f4560aba1961

commit r11-8205-gda879e01ecd35737c18be1da3324f4560aba1961
Author: Martin Sebor 
Date:   Thu Apr 15 15:49:30 2021 -0600

Propagate type attribute when merging extern declarations at local scope.

Resolves:
PR c/99420 - bogus -Warray-parameter on a function redeclaration in
function scope
PR c/99972 - missing -Wunused-result on a call to a locally redeclared
warn_unused_result function

gcc/c/ChangeLog:

PR c/99420
PR c/99972
* c-decl.c (pushdecl): Always propagate type attribute.

gcc/testsuite/ChangeLog:

PR c/99420
PR c/99972
* gcc.dg/Warray-parameter-9.c: New test.
* gcc.dg/Wnonnull-6.c: New test.
* gcc.dg/Wreturn-type3.c: New test.
* gcc.dg/Wunused-result.c: New test.
* gcc.dg/attr-noreturn.c: New test.
* gcc.dg/attr-returns-nonnull.c: New test.

[Bug c/99972] missing -Wunused-result on a call to a locally redeclared warn_unused_result function

2021-04-08 Thread msebor at gcc dot gnu.org via Gcc-bugs 
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=99972

Martin Sebor  changed:

   What|Removed |Added

 Ever confirmed|0   |1
   Assignee|unassigned at gcc dot gnu.org  |msebor at gcc dot 
gnu.org
   Last reconfirmed||2021-04-08
   Keywords||patch
 Status|UNCONFIRMED |ASSIGNED

--- Comment #3 from Martin Sebor  ---
Patch: https://gcc.gnu.org/pipermail/gcc-patches/2021-April/567800.html

[Bug c/99972] missing -Wunused-result on a call to a locally redeclared warn_unused_result function

2021-04-08 Thread msebor at gcc dot gnu.org via Gcc-bugs 
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=99972

--- Comment #2 from Martin Sebor  ---
The code (obviously) needs to be compiled as C to show the C bug (the C++ front
end is also buggy but differently; pr99974 tracks that):

$ gcc -S -Wall pr99972.c
pr99972.c: In function ‘gwur’:
pr99972.c:20:3: warning: ignoring return value of ‘fwur’ declared with
attribute ‘warn_unused_result’ [-Wunused-result]
   20 |   fwur ();   // -Wunused-result (good)
  |   ^~~

[Bug c/99972] missing -Wunused-result on a call to a locally redeclared warn_unused_result function

2021-04-08 Thread msebor at gcc dot gnu.org via Gcc-bugs 
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=99972

Martin Sebor  changed:

   What|Removed |Added

  Known to fail||10.2.0, 11.0, 4.7.0, 4.8.4,
   ||4.9.4, 5.5.0, 6.4.0, 7.2.0,
   ||8.3.0, 9.1.0
   Keywords||diagnostic

--- Comment #1 from Martin Sebor  ---
This never worked correctly so it's not a regression.

Clang does the right thing and warns where expected:

z.c:20:3: warning: ignoring return value of function declared with
  'warn_unused_result' attribute [-Wunused-result]
  fwur ();   // -Wunused-result (good)
  ^~~~
z.c:27:3: warning: ignoring return value of function declared with
  'warn_unused_result' attribute [-Wunused-result]
  fwur ();   // missing -Wunused-result (bug)
  ^~~~
2 warnings generated.