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* [Bug c++/99362] New: invalid unused result
@ 2021-03-03 15:36 gcc at cookiesoft dot de
  2021-03-03 15:52 ` [Bug c++/99362] " jakub at gcc dot gnu.org
                   ` (9 more replies)
  0 siblings, 10 replies; 11+ messages in thread
From: gcc at cookiesoft dot de @ 2021-03-03 15:36 UTC (permalink / raw)
  To: gcc-bugs

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=99362

            Bug ID: 99362
           Summary: invalid unused result
           Product: gcc
           Version: 10.2.1
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: c++
          Assignee: unassigned at gcc dot gnu.org
          Reporter: gcc at cookiesoft dot de
  Target Milestone: ---
            Target: arm

The following code will emit a warning on arm 32 bit compilers:

```
struct S {
    [[nodiscard]] S() {}
};

int main() {
    S s;
}
```

```
<source>: In function 'int main()':
<source>:6:7: warning: ignoring return value of 'S::S()', declared with
attribute 'nodiscard' [-Wunused-result]
    6 |     S s;
      |       ^
<source>:2:19: note: declared here
    2 |     [[nodiscard]] S() {}
      |                   ^
<source>:6:7: warning: ignoring return value of 'S::S()', declared with
attribute 'nodiscard' [-Wunused-result]
    6 |     S s;
      |       ^
<source>:2:19: note: declared here
    2 |     [[nodiscard]] S() {}
      |                   ^
Compiler returned: 0
```

```
S s = {}
```

does not emit such warning.

Does not emit a warning on x86 compiler though.
Does not emit a warning on 9.x branch, seems to be a regression.

Godbolt link: https://godbolt.org/z/4Kof1x

^ permalink raw reply	[flat|nested] 11+ messages in thread
end of thread, other threads:[~2021-04-23 12:37 UTC | newest]

Thread overview: 11+ messages (download: mbox.gz / follow: Atom feed)
-- links below jump to the message on this page --
2021-03-03 15:36 [Bug c++/99362] New: invalid unused result gcc at cookiesoft dot de
2021-03-03 15:52 ` [Bug c++/99362] " jakub at gcc dot gnu.org
2021-03-03 16:28 ` gcc at cookiesoft dot de
2021-03-03 17:37 ` harald at gigawatt dot nl
2021-03-03 19:16 ` [Bug c++/99362] [10/11 Regression] " jakub at gcc dot gnu.org
2021-03-03 19:44 ` jakub at gcc dot gnu.org
2021-03-04 15:05 ` cvs-commit at gcc dot gnu.org
2021-03-04 15:06 ` [Bug c++/99362] [10 " jakub at gcc dot gnu.org
2021-03-19 23:30 ` cvs-commit at gcc dot gnu.org
2021-03-20  8:09 ` jakub at gcc dot gnu.org
2021-04-23 12:37 ` jakub at gcc dot gnu.org

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