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* [Bug c++/111602] New: "Error: symbol is already defined" for variable template dependent on default argument lambda used in sfinae and non-sfinae
@ 2023-09-26 17:15 ed at catmur dot uk
2023-09-26 17:22 ` [Bug c++/111602] "Error: symbol is already defined" for variable template dependent on default argument lambda of class dependent on local type used in sfinae and non-sfinae contexts pinskia at gcc dot gnu.org
` (3 more replies)
0 siblings, 4 replies; 5+ messages in thread
From: ed at catmur dot uk @ 2023-09-26 17:15 UTC (permalink / raw)
To: gcc-bugs
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=111602
Bug ID: 111602
Summary: "Error: symbol is already defined" for variable
template dependent on default argument lambda used in
sfinae and non-sfinae
Product: gcc
Version: 14.0
Status: UNCONFIRMED
Severity: normal
Priority: P3
Component: c++
Assignee: unassigned at gcc dot gnu.org
Reporter: ed at catmur dot uk
Target Milestone: ---
Since gcc 8.1,
template<class> constexpr bool V = true;
struct F { template<class T, bool = V<T>> F(T) {} };
template<class T> struct C { C(F = []{}) {} };
template<class T> decltype(T()) g() { return T(); }
auto f() { struct T {} t; return t; };
int main() { g<C<decltype(f())>>(); }
compiled at -O0 (and -std=c++14 or above) causes assembler error:
/tmp/cccVZwwU.s: Assembler messages:
/tmp/cccVZwwU.s:106: Error: symbol `_Z1VIZN1CIZ1fvE1TEC4E1FEd_UlvE_E' is
already defined
The symbol demangles as 'V<C<f()::T>::C(F)::{default arg#1}::{lambda()#1}>'.
^ permalink raw reply [flat|nested] 5+ messages in thread
* [Bug c++/111602] "Error: symbol is already defined" for variable template dependent on default argument lambda of class dependent on local type used in sfinae and non-sfinae contexts
2023-09-26 17:15 [Bug c++/111602] New: "Error: symbol is already defined" for variable template dependent on default argument lambda used in sfinae and non-sfinae ed at catmur dot uk
@ 2023-09-26 17:22 ` pinskia at gcc dot gnu.org
2023-09-26 17:23 ` [Bug c++/111602] [11/12/13/14 Regression] " pinskia at gcc dot gnu.org
` (2 subsequent siblings)
3 siblings, 0 replies; 5+ messages in thread
From: pinskia at gcc dot gnu.org @ 2023-09-26 17:22 UTC (permalink / raw)
To: gcc-bugs
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=111602
Andrew Pinski <pinskia at gcc dot gnu.org> changed:
What |Removed |Added
----------------------------------------------------------------------------
Status|UNCONFIRMED |NEW
Last reconfirmed| |2023-09-26
Ever confirmed|0 |1
--- Comment #1 from Andrew Pinski <pinskia at gcc dot gnu.org> ---
Slightly reduced:
```
template<class> constexpr bool V = true;
struct F
{
template<class T, bool = V<T>>
F(T) {}
};
template<class T> struct C
{
C(F = []{}) {}
};
template<class T>
decltype(T()) g()
{
return T();
}
int main()
{
g<C<int>>();
}
```
The local type of f() is not needed.
^ permalink raw reply [flat|nested] 5+ messages in thread
* [Bug c++/111602] [11/12/13/14 Regression] "Error: symbol is already defined" for variable template dependent on default argument lambda of class dependent on local type used in sfinae and non-sfinae contexts
2023-09-26 17:15 [Bug c++/111602] New: "Error: symbol is already defined" for variable template dependent on default argument lambda used in sfinae and non-sfinae ed at catmur dot uk
2023-09-26 17:22 ` [Bug c++/111602] "Error: symbol is already defined" for variable template dependent on default argument lambda of class dependent on local type used in sfinae and non-sfinae contexts pinskia at gcc dot gnu.org
@ 2023-09-26 17:23 ` pinskia at gcc dot gnu.org
2023-09-26 19:33 ` ed at catmur dot uk
2023-10-25 20:15 ` ppalka at gcc dot gnu.org
3 siblings, 0 replies; 5+ messages in thread
From: pinskia at gcc dot gnu.org @ 2023-09-26 17:23 UTC (permalink / raw)
To: gcc-bugs
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=111602
Andrew Pinski <pinskia at gcc dot gnu.org> changed:
What |Removed |Added
----------------------------------------------------------------------------
Summary|"Error: symbol is already |[11/12/13/14 Regression]
|defined" for variable |"Error: symbol is already
|template dependent on |defined" for variable
|default argument lambda of |template dependent on
|class dependent on local |default argument lambda of
|type used in sfinae and |class dependent on local
|non-sfinae contexts |type used in sfinae and
| |non-sfinae contexts
Target Milestone|--- |11.5
Known to fail| |8.1.0
Known to work| |7.1.0
^ permalink raw reply [flat|nested] 5+ messages in thread
* [Bug c++/111602] [11/12/13/14 Regression] "Error: symbol is already defined" for variable template dependent on default argument lambda of class dependent on local type used in sfinae and non-sfinae contexts
2023-09-26 17:15 [Bug c++/111602] New: "Error: symbol is already defined" for variable template dependent on default argument lambda used in sfinae and non-sfinae ed at catmur dot uk
2023-09-26 17:22 ` [Bug c++/111602] "Error: symbol is already defined" for variable template dependent on default argument lambda of class dependent on local type used in sfinae and non-sfinae contexts pinskia at gcc dot gnu.org
2023-09-26 17:23 ` [Bug c++/111602] [11/12/13/14 Regression] " pinskia at gcc dot gnu.org
@ 2023-09-26 19:33 ` ed at catmur dot uk
2023-10-25 20:15 ` ppalka at gcc dot gnu.org
3 siblings, 0 replies; 5+ messages in thread
From: ed at catmur dot uk @ 2023-09-26 19:33 UTC (permalink / raw)
To: gcc-bugs
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=111602
--- Comment #2 from Ed Catmur <ed at catmur dot uk> ---
(In reply to Andrew Pinski from comment #1)
> The local type of f() is not needed.
Thanks! I was confused since the local type is required in this similar
example:
template<class> struct P
{
static constexpr bool value = true;
};
template<class T> constexpr bool P<T>::value;
template<bool> struct E {};
struct F
{
template<class T, class = E<P<T>::value>>
F(T) {}
};
template<class> struct C
{
C(F = []{}) {}
};
auto f()
{
struct T {} t;
return t;
}
template<class T>
decltype(T()) g()
{
return T();
}
int main()
{
g<C<decltype(f)>>();
}
^ permalink raw reply [flat|nested] 5+ messages in thread
* [Bug c++/111602] [11/12/13/14 Regression] "Error: symbol is already defined" for variable template dependent on default argument lambda of class dependent on local type used in sfinae and non-sfinae contexts
2023-09-26 17:15 [Bug c++/111602] New: "Error: symbol is already defined" for variable template dependent on default argument lambda used in sfinae and non-sfinae ed at catmur dot uk
` (2 preceding siblings ...)
2023-09-26 19:33 ` ed at catmur dot uk
@ 2023-10-25 20:15 ` ppalka at gcc dot gnu.org
3 siblings, 0 replies; 5+ messages in thread
From: ppalka at gcc dot gnu.org @ 2023-10-25 20:15 UTC (permalink / raw)
To: gcc-bugs
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=111602
Patrick Palka <ppalka at gcc dot gnu.org> changed:
What |Removed |Added
----------------------------------------------------------------------------
CC| |ppalka at gcc dot gnu.org
--- Comment #3 from Patrick Palka <ppalka at gcc dot gnu.org> ---
Started with r8-2720-gf44a8dd56f5bfb FWIW
^ permalink raw reply [flat|nested] 5+ messages in thread
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2023-09-26 17:15 [Bug c++/111602] New: "Error: symbol is already defined" for variable template dependent on default argument lambda used in sfinae and non-sfinae ed at catmur dot uk
2023-09-26 17:22 ` [Bug c++/111602] "Error: symbol is already defined" for variable template dependent on default argument lambda of class dependent on local type used in sfinae and non-sfinae contexts pinskia at gcc dot gnu.org
2023-09-26 17:23 ` [Bug c++/111602] [11/12/13/14 Regression] " pinskia at gcc dot gnu.org
2023-09-26 19:33 ` ed at catmur dot uk
2023-10-25 20:15 ` ppalka at gcc dot gnu.org
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