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* [Bug c++/109425] New: mismatched argument pack lengths while expanding
@ 2023-04-05 19:53 h2+bugs at fsfe dot org
2023-04-05 20:16 ` [Bug c++/109425] " mpolacek at gcc dot gnu.org
` (3 more replies)
0 siblings, 4 replies; 5+ messages in thread
From: h2+bugs at fsfe dot org @ 2023-04-05 19:53 UTC (permalink / raw)
To: gcc-bugs
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=109425
Bug ID: 109425
Summary: mismatched argument pack lengths while expanding
Product: gcc
Version: 12.2.1
Status: UNCONFIRMED
Severity: normal
Priority: P3
Component: c++
Assignee: unassigned at gcc dot gnu.org
Reporter: h2+bugs at fsfe dot org
Target Milestone: ---
The following snippet is rejected by GCC10, GCC11 and GCC12:
```cpp
#include <concepts>
template <typename T1, typename T2>
concept weakly_eq_comparable = requires (T1 t1, T2 t2) { { t1 == t2 } ->
std::convertible_to<bool>; };
template <typename ...Ts>
struct my_tuple
{
template <typename ...T2s>
requires ((sizeof...(Ts) == sizeof...(T2s)) && (weakly_eq_comparable<Ts,
T2s> && ...))
friend bool operator==(my_tuple const & lhs, my_tuple<T2s...> const & rhs)
{
return true;
}
};
int main()
{
my_tuple<int, float> m1;
}
```
See also:
https://godbolt.org/z/3eEjT589o
The error is:
```
<source>: In instantiation of 'struct my_tuple<int, float>':
<source>:20:26: required from here
<source>:11:86: error: mismatched argument pack lengths while expanding
'weakly_eq_comparable<Ts, T2s>'
11 | requires ((sizeof...(Ts) == sizeof...(T2s)) &&
(weakly_eq_comparable<Ts, T2s> && ...))
|
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~^~~~
Compiler returned: 1
```
Clang>=13 accepts this code.
I am not sure if this is related to #107853, because I am not getting an ICE,
but it seems like the problems (or their solutions) could be related.
Thank you!
^ permalink raw reply [flat|nested] 5+ messages in thread
* [Bug c++/109425] mismatched argument pack lengths while expanding
2023-04-05 19:53 [Bug c++/109425] New: mismatched argument pack lengths while expanding h2+bugs at fsfe dot org
@ 2023-04-05 20:16 ` mpolacek at gcc dot gnu.org
2023-04-05 23:09 ` h2+bugs at fsfe dot org
` (2 subsequent siblings)
3 siblings, 0 replies; 5+ messages in thread
From: mpolacek at gcc dot gnu.org @ 2023-04-05 20:16 UTC (permalink / raw)
To: gcc-bugs
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=109425
Marek Polacek <mpolacek at gcc dot gnu.org> changed:
What |Removed |Added
----------------------------------------------------------------------------
Status|UNCONFIRMED |RESOLVED
Resolution|--- |DUPLICATE
CC| |mpolacek at gcc dot gnu.org
--- Comment #1 from Marek Polacek <mpolacek at gcc dot gnu.org> ---
Seems to have been fixed by r13-4876-gbd1fc4a219d8c0
commit bd1fc4a219d8c0fad0ec41002e895b49e384c1c2
Author: Patrick Palka <ppalka@redhat.com>
Date: Fri Dec 23 09:18:37 2022 -0500
c++: template friend with variadic constraints [PR107853]
so it is related to bug 107853. In fact I think we can say it's a dup.
*** This bug has been marked as a duplicate of bug 107853 ***
^ permalink raw reply [flat|nested] 5+ messages in thread
* [Bug c++/109425] mismatched argument pack lengths while expanding
2023-04-05 19:53 [Bug c++/109425] New: mismatched argument pack lengths while expanding h2+bugs at fsfe dot org
2023-04-05 20:16 ` [Bug c++/109425] " mpolacek at gcc dot gnu.org
@ 2023-04-05 23:09 ` h2+bugs at fsfe dot org
2023-04-06 13:18 ` mpolacek at gcc dot gnu.org
2023-04-06 13:25 ` ppalka at gcc dot gnu.org
3 siblings, 0 replies; 5+ messages in thread
From: h2+bugs at fsfe dot org @ 2023-04-05 23:09 UTC (permalink / raw)
To: gcc-bugs
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=109425
--- Comment #2 from Hannes Hauswedell <h2+bugs at fsfe dot org> ---
Thanks for the quick reply, and nice that it is already fixed for 13!
I assume this will not be backported? It wouldn't be a huge problem, because it
is possible to workaround with non-friend operators.
^ permalink raw reply [flat|nested] 5+ messages in thread
* [Bug c++/109425] mismatched argument pack lengths while expanding
2023-04-05 19:53 [Bug c++/109425] New: mismatched argument pack lengths while expanding h2+bugs at fsfe dot org
2023-04-05 20:16 ` [Bug c++/109425] " mpolacek at gcc dot gnu.org
2023-04-05 23:09 ` h2+bugs at fsfe dot org
@ 2023-04-06 13:18 ` mpolacek at gcc dot gnu.org
2023-04-06 13:25 ` ppalka at gcc dot gnu.org
3 siblings, 0 replies; 5+ messages in thread
From: mpolacek at gcc dot gnu.org @ 2023-04-06 13:18 UTC (permalink / raw)
To: gcc-bugs
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=109425
--- Comment #3 from Marek Polacek <mpolacek at gcc dot gnu.org> ---
(In reply to Hannes Hauswedell from comment #2)
> Thanks for the quick reply, and nice that it is already fixed for 13!
>
> I assume this will not be backported? It wouldn't be a huge problem, because
> it is possible to workaround with non-friend operators.
I think this is up to Patrick to decide.
^ permalink raw reply [flat|nested] 5+ messages in thread
* [Bug c++/109425] mismatched argument pack lengths while expanding
2023-04-05 19:53 [Bug c++/109425] New: mismatched argument pack lengths while expanding h2+bugs at fsfe dot org
` (2 preceding siblings ...)
2023-04-06 13:18 ` mpolacek at gcc dot gnu.org
@ 2023-04-06 13:25 ` ppalka at gcc dot gnu.org
3 siblings, 0 replies; 5+ messages in thread
From: ppalka at gcc dot gnu.org @ 2023-04-06 13:25 UTC (permalink / raw)
To: gcc-bugs
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=109425
Patrick Palka <ppalka at gcc dot gnu.org> changed:
What |Removed |Added
----------------------------------------------------------------------------
CC| |ppalka at gcc dot gnu.org
--- Comment #4 from Patrick Palka <ppalka at gcc dot gnu.org> ---
(In reply to Hannes Hauswedell from comment #2)
> Thanks for the quick reply, and nice that it is already fixed for 13!
>
> I assume this will not be backported? It wouldn't be a huge problem, because
> it is possible to workaround with non-friend operators.
It's already been backported to the 12 branch, so the upcoming GCC 12.3 (or a
recent enough snapshot of the release branch) will also include the fix. No
decision yet about backporting to the 11/10 branches. Having to work around
this by defining these functions as non-friends is pretty inconvenient..
^ permalink raw reply [flat|nested] 5+ messages in thread
end of thread, other threads:[~2023-04-06 13:25 UTC | newest]
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2023-04-05 19:53 [Bug c++/109425] New: mismatched argument pack lengths while expanding h2+bugs at fsfe dot org
2023-04-05 20:16 ` [Bug c++/109425] " mpolacek at gcc dot gnu.org
2023-04-05 23:09 ` h2+bugs at fsfe dot org
2023-04-06 13:18 ` mpolacek at gcc dot gnu.org
2023-04-06 13:25 ` ppalka at gcc dot gnu.org
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