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* [Bug c++/95368] New: gcc things that a lambda capture is both const and mutable
@ 2020-05-27 15:24 rafael at espindo dot la
2020-05-27 16:35 ` [Bug c++/95368] " daniel.kruegler at googlemail dot com
` (4 more replies)
0 siblings, 5 replies; 6+ messages in thread
From: rafael at espindo dot la @ 2020-05-27 15:24 UTC (permalink / raw)
To: gcc-bugs
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=95368
Bug ID: 95368
Summary: gcc things that a lambda capture is both const and
mutable
Product: gcc
Version: unknown
Status: UNCONFIRMED
Severity: normal
Priority: P3
Component: c++
Assignee: unassigned at gcc dot gnu.org
Reporter: rafael at espindo dot la
Target Milestone: ---
gcc accepts
#include <utility>
struct foo {
void func();
};
void bar(foo& v) {
[v]() {
static_assert(std::is_same_v<decltype(v), foo&>);
[v]() mutable {
static_assert(std::is_same_v<decltype(v), foo&>);
// v.func();
}();
}();
}
But uncomment the call and you get
test.cc:12:20: error: passing ‘const foo’ as ‘this’ argument discards
qualifiers [-fpermissive]
12 | v.func();
^ permalink raw reply [flat|nested] 6+ messages in thread* [Bug c++/95368] gcc things that a lambda capture is both const and mutable
2020-05-27 15:24 [Bug c++/95368] New: gcc things that a lambda capture is both const and mutable rafael at espindo dot la
@ 2020-05-27 16:35 ` daniel.kruegler at googlemail dot com
2020-05-28 17:00 ` rafael at espindo dot la
` (3 subsequent siblings)
4 siblings, 0 replies; 6+ messages in thread
From: daniel.kruegler at googlemail dot com @ 2020-05-27 16:35 UTC (permalink / raw)
To: gcc-bugs
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=95368
Daniel Krügler <daniel.kruegler at googlemail dot com> changed:
What |Removed |Added
----------------------------------------------------------------------------
CC| |daniel.kruegler@googlemail.
| |com
--- Comment #1 from Daniel Krügler <daniel.kruegler at googlemail dot com> ---
(In reply to Rafael Avila de Espindola from comment #0)
> gcc accepts
>
[..]
I found your code confusing, because the actual problem becomes visible only
under certain conditions. So lets make it a proper example, that shows the
problem immediately and lets ensure that we make it free from library
dependencies and provide all required information:
When using
gcc HEAD 11.0.0 20200525 (experimental)
and the following compiler flags
-Wall -Wextra -std=gnu++2a -pedantic
to compile this code:
//---------
template<class, class>
constexpr bool is_same_v = false;
template<class T>
constexpr bool is_same_v<T, T> = true;
struct foo
{
void func() {}
};
void bar(foo& v) {
[v]() {
static_assert(is_same_v<decltype(v), foo&>);
[v]() mutable {
static_assert(is_same_v<decltype(v), foo&>);
v.func();
}();
}();
}
int main() {}
//---------
the program is rejected (but should be accepted) with the following
diagnostics:
```
prog.cc: In lambda function:
prog.cc:17:16: error: passing 'const foo' as 'this' argument discards
qualifiers [-fpermissive]
17 | v.func();
| ^
prog.cc:9:8: note: in call to 'void foo::func()'
9 | void func() {}
| ^~~~
```
^ permalink raw reply [flat|nested] 6+ messages in thread* [Bug c++/95368] gcc things that a lambda capture is both const and mutable
2020-05-27 15:24 [Bug c++/95368] New: gcc things that a lambda capture is both const and mutable rafael at espindo dot la
2020-05-27 16:35 ` [Bug c++/95368] " daniel.kruegler at googlemail dot com
@ 2020-05-28 17:00 ` rafael at espindo dot la
2021-12-28 9:55 ` pinskia at gcc dot gnu.org
` (2 subsequent siblings)
4 siblings, 0 replies; 6+ messages in thread
From: rafael at espindo dot la @ 2020-05-28 17:00 UTC (permalink / raw)
To: gcc-bugs
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=95368
--- Comment #2 from Rafael Avila de Espindola <rafael at espindo dot la> ---
I just tested a few compilers with the testcase from comment 1:
* clang version 11.0.0 (https://github.com/llvm/llvm-project.git
0796b170fb3bf38e6cc4e59746120b37c9a9cd9f):
Accepts it.
* g++ (GCC) 10.1.1 20200507 (Red Hat 10.1.1-1):
Rejects it:
test.cc:17:14: error: passing ‘const foo’ as ‘this’ argument discards
qualifiers [-fpermissive]
* gcc (GCC) 9.3.1 20200528
Rejects it:
test.cc:17:14: error: passing ‘const foo’ as ‘this’ argument discards
qualifiers
^ permalink raw reply [flat|nested] 6+ messages in thread* [Bug c++/95368] gcc things that a lambda capture is both const and mutable
2020-05-27 15:24 [Bug c++/95368] New: gcc things that a lambda capture is both const and mutable rafael at espindo dot la
2020-05-27 16:35 ` [Bug c++/95368] " daniel.kruegler at googlemail dot com
2020-05-28 17:00 ` rafael at espindo dot la
@ 2021-12-28 9:55 ` pinskia at gcc dot gnu.org
2021-12-28 9:56 ` pinskia at gcc dot gnu.org
2021-12-28 10:01 ` pinskia at gcc dot gnu.org
4 siblings, 0 replies; 6+ messages in thread
From: pinskia at gcc dot gnu.org @ 2021-12-28 9:55 UTC (permalink / raw)
To: gcc-bugs
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=95368
Andrew Pinski <pinskia at gcc dot gnu.org> changed:
What |Removed |Added
----------------------------------------------------------------------------
Known to fail| |11.1.0
Known to work| |12.0
Keywords| |needs-bisection
--- Comment #3 from Andrew Pinski <pinskia at gcc dot gnu.org> ---
Looks to be fixed on the trunk.
^ permalink raw reply [flat|nested] 6+ messages in thread* [Bug c++/95368] gcc things that a lambda capture is both const and mutable
2020-05-27 15:24 [Bug c++/95368] New: gcc things that a lambda capture is both const and mutable rafael at espindo dot la
` (2 preceding siblings ...)
2021-12-28 9:55 ` pinskia at gcc dot gnu.org
@ 2021-12-28 9:56 ` pinskia at gcc dot gnu.org
2021-12-28 10:01 ` pinskia at gcc dot gnu.org
4 siblings, 0 replies; 6+ messages in thread
From: pinskia at gcc dot gnu.org @ 2021-12-28 9:56 UTC (permalink / raw)
To: gcc-bugs
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=95368
Andrew Pinski <pinskia at gcc dot gnu.org> changed:
What |Removed |Added
----------------------------------------------------------------------------
Last reconfirmed| |2021-12-28
Ever confirmed|0 |1
Status|UNCONFIRMED |NEW
^ permalink raw reply [flat|nested] 6+ messages in thread* [Bug c++/95368] gcc things that a lambda capture is both const and mutable
2020-05-27 15:24 [Bug c++/95368] New: gcc things that a lambda capture is both const and mutable rafael at espindo dot la
` (3 preceding siblings ...)
2021-12-28 9:56 ` pinskia at gcc dot gnu.org
@ 2021-12-28 10:01 ` pinskia at gcc dot gnu.org
4 siblings, 0 replies; 6+ messages in thread
From: pinskia at gcc dot gnu.org @ 2021-12-28 10:01 UTC (permalink / raw)
To: gcc-bugs
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=95368
Andrew Pinski <pinskia at gcc dot gnu.org> changed:
What |Removed |Added
----------------------------------------------------------------------------
Status|NEW |RESOLVED
Resolution|--- |DUPLICATE
--- Comment #4 from Andrew Pinski <pinskia at gcc dot gnu.org> ---
Dup of bug 94376
*** This bug has been marked as a duplicate of bug 94376 ***
^ permalink raw reply [flat|nested] 6+ messages in thread
end of thread, other threads:[~2021-12-28 10:01 UTC | newest]
Thread overview: 6+ messages (download: mbox.gz / follow: Atom feed)
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2020-05-27 15:24 [Bug c++/95368] New: gcc things that a lambda capture is both const and mutable rafael at espindo dot la
2020-05-27 16:35 ` [Bug c++/95368] " daniel.kruegler at googlemail dot com
2020-05-28 17:00 ` rafael at espindo dot la
2021-12-28 9:55 ` pinskia at gcc dot gnu.org
2021-12-28 9:56 ` pinskia at gcc dot gnu.org
2021-12-28 10:01 ` pinskia at gcc dot gnu.org
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