Re: c++/45: Template Specialization

[Wolfgang Bangerth <bangerth@ticam.utexas.edu>]

The following reply was made to PR c++/45; it has been noted by GNATS.

From: Wolfgang Bangerth <bangerth@ticam.utexas.edu>
To: gcc-bugs@gcc.gnu.org, <gcc-gnats@gcc.gnu.org>
Cc:  
Subject: Re: c++/45: Template Specialization
Date: Tue, 22 Oct 2002 18:51:23 -0500 (CDT)

 Someone should re-name this report to
   "Matching of partial specialization of classes"
 
 Here's a redux:
 -----------------------------------------
 template <int N>  struct Int {};
 template <char C> struct Char{};
 
 template <typename A, typename B> struct X;
 
 template <char C, int N> struct X< Char<C>, Int<N> > { typedef Int<C> val; };
 template <int N, char C> struct X< Int<N>, Char<C> > { typedef Int<N> val; };
 
 X< Int<0>, Char<'1'> >::val i;
 ----------------------------------------
 
 In ways I don't understand, this bug goes away if in the declaration of 
 the second partial specialization, "int N" and "char C" is reversed, 
 something that should have absolutely no effect on matching of templates. 
 In some other ways I do not understand either, the problem also goes away 
 if I change the template argument of "Char" from "char" to "int", 
 something that should also not affect matching, but does.
 
 Regards
   Wolfgang
 
 -------------------------------------------------------------------------
 Wolfgang Bangerth              email:           bangerth@ticam.utexas.edu
                                www: http://www.ticam.utexas.edu/~bangerth