------- Comment #2 from pinskia at gmail dot com 2010-07-21 02:53 -------
Subject: Re: New: Invalid ambiguity on partial class specialization matching
On Jul 20, 2010, at 7:43 PM, "rodolfo at rodsoft dot org"
<gcc-bugzi...@gcc.gnu.org
> wrote:
> The following code doesn't compile unless variable RUNTIME is
> defined as a
> "static const int" instead of an "enum":
>
This enum value has an anonymous type which is not valid in the
context of templates in C++03/98. It is valid in the current draft of C
++0x though. But I cannot remember if 4.5 implements that rule for -
std=gnu++0x (-std=c++0x).
> #include <type_traits>
>
> enum { RUNTIME = 0 };
> // it compiles with the previous line commented out and the next
> commented in
> // static const int RUNTIME=0;
>
> template <class T, class U, class EN=void> struct foo;
>
> template <template<int> class V, int M>
> struct foo<V<M>,V<M>, typename std::enable_if<M==RUNTIME ||
> M==2>::type> {};
>
> template <template<int> class V1, template<int> class V2, int M>
> struct foo<V1<M>,V2<M>, typename std::enable_if<M==RUNTIME ||
> M==2>::type> {};
>
> template <int M> struct bar {};
>
> foo<bar<2>,bar<2>> x;
>
>
> --
> Summary: Invalid ambiguity on partial class specialization
> matching
> Product: gcc
> Version: 4.5.0
> Status: UNCONFIRMED
> Severity: normal
> Priority: P3
> Component: c++
> AssignedTo: unassigned at gcc dot gnu dot org
> ReportedBy: rodolfo at rodsoft dot org
> GCC build triplet: x86_64-pc-linux-gnu
> GCC host triplet: x86_64-pc-linux-gnu
> GCC target triplet: x86_64-pc-linux-gnu
>
>
> http://gcc.gnu.org/bugzilla/show_bug.cgi?id=45012
>
--
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=45012
