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* [Bug c++/107111] New: GCC accepts invalid program involving function declaration with pack expansion
@ 2022-10-01 17:05 jlame646 at gmail dot com
2022-10-01 17:11 ` [Bug c++/107111] " jlame646 at gmail dot com
` (4 more replies)
0 siblings, 5 replies; 6+ messages in thread
From: jlame646 at gmail dot com @ 2022-10-01 17:05 UTC (permalink / raw)
To: gcc-bugs
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=107111
Bug ID: 107111
Summary: GCC accepts invalid program involving function
declaration with pack expansion
Product: gcc
Version: 12.1.1
Status: UNCONFIRMED
Severity: normal
Priority: P3
Component: c++
Assignee: unassigned at gcc dot gnu.org
Reporter: jlame646 at gmail dot com
Target Milestone: ---
The following program is incorrectly accepted by gcc. Demo:
https://godbolt.org/z/rvfqzo5YW
```
template<typename T, typename... V>
struct C
{
T v(V()...);;
};
int main()
{
C<int> c; //works with gcc but rejected in clang
C<int, double, int, int> c2; //same here: works with gcc but rejected in
clang
}
```
This is invalid because the construct `V()...` is actually equivalent to
`V(),...`. So `V` is not expanded and this must be rejected.
^ permalink raw reply [flat|nested] 6+ messages in thread
* [Bug c++/107111] GCC accepts invalid program involving function declaration with pack expansion
2022-10-01 17:05 [Bug c++/107111] New: GCC accepts invalid program involving function declaration with pack expansion jlame646 at gmail dot com
@ 2022-10-01 17:11 ` jlame646 at gmail dot com
2022-10-01 17:24 ` jlame646 at gmail dot com
` (3 subsequent siblings)
4 siblings, 0 replies; 6+ messages in thread
From: jlame646 at gmail dot com @ 2022-10-01 17:11 UTC (permalink / raw)
To: gcc-bugs
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=107111
--- Comment #1 from Jason Liam <jlame646 at gmail dot com> ---
The last statement in my original report is not valid because `V` is a template
parameter pack. So ignore that line.
^ permalink raw reply [flat|nested] 6+ messages in thread
* [Bug c++/107111] GCC accepts invalid program involving function declaration with pack expansion
2022-10-01 17:05 [Bug c++/107111] New: GCC accepts invalid program involving function declaration with pack expansion jlame646 at gmail dot com
2022-10-01 17:11 ` [Bug c++/107111] " jlame646 at gmail dot com
@ 2022-10-01 17:24 ` jlame646 at gmail dot com
2022-10-02 4:34 ` iamsupermouse at mail dot ru
` (2 subsequent siblings)
4 siblings, 0 replies; 6+ messages in thread
From: jlame646 at gmail dot com @ 2022-10-01 17:24 UTC (permalink / raw)
To: gcc-bugs
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=107111
--- Comment #2 from Jason Liam <jlame646 at gmail dot com> ---
Also gcc rejects `V...()` but clang accepts that. Demo:
https://godbolt.org/z/bfx9rv6hP
^ permalink raw reply [flat|nested] 6+ messages in thread
* [Bug c++/107111] GCC accepts invalid program involving function declaration with pack expansion
2022-10-01 17:05 [Bug c++/107111] New: GCC accepts invalid program involving function declaration with pack expansion jlame646 at gmail dot com
2022-10-01 17:11 ` [Bug c++/107111] " jlame646 at gmail dot com
2022-10-01 17:24 ` jlame646 at gmail dot com
@ 2022-10-02 4:34 ` iamsupermouse at mail dot ru
2022-10-02 4:35 ` iamsupermouse at mail dot ru
2022-10-02 9:47 ` jlame646 at gmail dot com
4 siblings, 0 replies; 6+ messages in thread
From: iamsupermouse at mail dot ru @ 2022-10-02 4:34 UTC (permalink / raw)
To: gcc-bugs
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=107111
Egor <iamsupermouse at mail dot ru> changed:
What |Removed |Added
----------------------------------------------------------------------------
CC| |iamsupermouse at mail dot ru
--- Comment #3 from Egor <iamsupermouse at mail dot ru> ---
The correct behavior should be to accept `V...()` and to reject `V()...`.
^ permalink raw reply [flat|nested] 6+ messages in thread
* [Bug c++/107111] GCC accepts invalid program involving function declaration with pack expansion
2022-10-01 17:05 [Bug c++/107111] New: GCC accepts invalid program involving function declaration with pack expansion jlame646 at gmail dot com
` (2 preceding siblings ...)
2022-10-02 4:34 ` iamsupermouse at mail dot ru
@ 2022-10-02 4:35 ` iamsupermouse at mail dot ru
2022-10-02 9:47 ` jlame646 at gmail dot com
4 siblings, 0 replies; 6+ messages in thread
From: iamsupermouse at mail dot ru @ 2022-10-02 4:35 UTC (permalink / raw)
To: gcc-bugs
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=107111
--- Comment #4 from Egor <iamsupermouse at mail dot ru> ---
*** Bug 107113 has been marked as a duplicate of this bug. ***
^ permalink raw reply [flat|nested] 6+ messages in thread
* [Bug c++/107111] GCC accepts invalid program involving function declaration with pack expansion
2022-10-01 17:05 [Bug c++/107111] New: GCC accepts invalid program involving function declaration with pack expansion jlame646 at gmail dot com
` (3 preceding siblings ...)
2022-10-02 4:35 ` iamsupermouse at mail dot ru
@ 2022-10-02 9:47 ` jlame646 at gmail dot com
4 siblings, 0 replies; 6+ messages in thread
From: jlame646 at gmail dot com @ 2022-10-02 9:47 UTC (permalink / raw)
To: gcc-bugs
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=107111
--- Comment #5 from Jason Liam <jlame646 at gmail dot com> ---
Note also that gcc accepts `T v(V...b())` but rejects `T v(V...())`. Note the
use of parameter name in the former. Demo: https://godbolt.org/z/hMevdc8TE
^ permalink raw reply [flat|nested] 6+ messages in thread
end of thread, other threads:[~2022-10-02 9:47 UTC | newest]
Thread overview: 6+ messages (download: mbox.gz / follow: Atom feed)
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2022-10-01 17:05 [Bug c++/107111] New: GCC accepts invalid program involving function declaration with pack expansion jlame646 at gmail dot com
2022-10-01 17:11 ` [Bug c++/107111] " jlame646 at gmail dot com
2022-10-01 17:24 ` jlame646 at gmail dot com
2022-10-02 4:34 ` iamsupermouse at mail dot ru
2022-10-02 4:35 ` iamsupermouse at mail dot ru
2022-10-02 9:47 ` jlame646 at gmail dot com
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