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* [Bug c++/47513] New: [C++0x] [SFINAE] compiler rejects valid code
@ 2011-01-28 13:33 s.gesemann at gmail dot com
2011-01-28 14:59 ` [Bug c++/47513] " redi at gcc dot gnu.org
2011-04-08 15:22 ` jason at gcc dot gnu.org
0 siblings, 2 replies; 3+ messages in thread
From: s.gesemann at gmail dot com @ 2011-01-28 13:33 UTC (permalink / raw)
To: gcc-bugs
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=47513
Summary: [C++0x] [SFINAE] compiler rejects valid code
Product: gcc
Version: 4.5.1
Status: UNCONFIRMED
Severity: normal
Priority: P3
Component: c++
AssignedTo: unassigned@gcc.gnu.org
ReportedBy: s.gesemann@gmail.com
I believe the following code should compile using the option -std=c++0x:
struct use_copy_ctor {};
struct prefer_clone_func : use_copy_ctor {};
template<class T>
auto clone(T const* ptr, prefer_clone_func)
-> decltype(ptr->clone())
{ return ptr->clone(); }
template<class T>
auto clone(T const* ptr, use_copy_ctor)
-> decltype(new T(*ptr))
{ return new T(*ptr); }
struct abc {
virtual ~abc() {}
virtual abc* clone() const =0;
};
struct derived : abc
{
derived* clone() const { return new derived(*this); }
};
int main()
{
derived d;
abc* p = &d;
abc* q = clone(p,prefer_clone_func());
delete q;
}
As far as I can tell SFINAE applies during template argument deduction where
abc is substituted for T in decltype(new T(*ptr)). GCC complains about abc
being abstract -- which it is, of course -- but it should instead simply ignore
the second function template.
Related note: Assuming std::is_constructible is implemented in terms of
decltype, this would explain why std::is_constructible doesn't work either on
abstract class types.
^ permalink raw reply [flat|nested] 3+ messages in thread
* [Bug c++/47513] [C++0x] [SFINAE] compiler rejects valid code
2011-01-28 13:33 [Bug c++/47513] New: [C++0x] [SFINAE] compiler rejects valid code s.gesemann at gmail dot com
@ 2011-01-28 14:59 ` redi at gcc dot gnu.org
2011-04-08 15:22 ` jason at gcc dot gnu.org
1 sibling, 0 replies; 3+ messages in thread
From: redi at gcc dot gnu.org @ 2011-01-28 14:59 UTC (permalink / raw)
To: gcc-bugs
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=47513
Jonathan Wakely <redi at gcc dot gnu.org> changed:
What |Removed |Added
----------------------------------------------------------------------------
Keywords| |rejects-valid
Status|UNCONFIRMED |NEW
Last reconfirmed| |2011.01.28 14:43:43
Ever Confirmed|0 |1
--- Comment #1 from Jonathan Wakely <redi at gcc dot gnu.org> 2011-01-28 14:43:43 UTC ---
I think you're right - so confirmed
^ permalink raw reply [flat|nested] 3+ messages in thread
* [Bug c++/47513] [C++0x] [SFINAE] compiler rejects valid code
2011-01-28 13:33 [Bug c++/47513] New: [C++0x] [SFINAE] compiler rejects valid code s.gesemann at gmail dot com
2011-01-28 14:59 ` [Bug c++/47513] " redi at gcc dot gnu.org
@ 2011-04-08 15:22 ` jason at gcc dot gnu.org
1 sibling, 0 replies; 3+ messages in thread
From: jason at gcc dot gnu.org @ 2011-04-08 15:22 UTC (permalink / raw)
To: gcc-bugs
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=47513
Jason Merrill <jason at gcc dot gnu.org> changed:
What |Removed |Added
----------------------------------------------------------------------------
Status|NEW |RESOLVED
CC| |jason at gcc dot gnu.org
Resolution| |FIXED
Target Milestone|--- |4.7.0
--- Comment #2 from Jason Merrill <jason at gcc dot gnu.org> 2011-04-08 15:22:20 UTC ---
Fixed for 4.7.0 by patch for PR 48449.
^ permalink raw reply [flat|nested] 3+ messages in thread
end of thread, other threads:[~2011-04-08 15:22 UTC | newest]
Thread overview: 3+ messages (download: mbox.gz / follow: Atom feed)
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2011-01-28 13:33 [Bug c++/47513] New: [C++0x] [SFINAE] compiler rejects valid code s.gesemann at gmail dot com
2011-01-28 14:59 ` [Bug c++/47513] " redi at gcc dot gnu.org
2011-04-08 15:22 ` jason at gcc dot gnu.org
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