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From: "redi at gcc dot gnu.org" <gcc-bugzilla@gcc.gnu.org>
To: gcc-bugs@gcc.gnu.org
Subject: [Bug c++/40127] Fails to identify template function with default args
Date: Sun, 15 Jan 2012 23:26:00 -0000	[thread overview]
Message-ID: <bug-40127-4-pTqPprtKyh@http.gcc.gnu.org/bugzilla/> (raw)
In-Reply-To: <bug-40127-4@http.gcc.gnu.org/bugzilla/>

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=40127

--- Comment #2 from Jonathan Wakely <redi at gcc dot gnu.org> 2012-01-15 23:16:53 UTC ---
(In reply to comment #0)
> I'm not sure whether argument types can be bound from default arguments in the
> standard,

They can't.

> but if they can't then I should get a diagnostic at the declaration
> of the template.

As Andrew showed, the template isn't invalid and can be called with an explicit
template argument list, so issuing a diagnostic at declaration would be wrong.

> The actual message is cryptic and unhelpful.

Current versions give a great diagnostic:

c.cc: In function ‘int main()’:
c.cc:4:14: error: no matching function for call to ‘foo(int)’
c.cc:4:14: note: candidate is:
c.cc:2:9: note: template<class T> void foo(int, void (*)(T*), T*)
c.cc:2:9: note:   template argument deduction/substitution failed:
c.cc:4:14: note:   couldn't deduce template parameter ‘T’


      parent reply	other threads:[~2012-01-15 23:17 UTC|newest]

Thread overview: 2+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
     [not found] <bug-40127-4@http.gcc.gnu.org/bugzilla/>
2012-01-15 20:27 ` pinskia at gcc dot gnu.org
2012-01-15 23:26 ` redi at gcc dot gnu.org [this message]

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