[Bug c++/49637] template function overload incorrectly ambiguous

["timothyjgiese at gmail dot com" <gcc-bugzilla at gcc dot gnu dot org>]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=49637

Timothy J Giese <timothyjgiese at gmail dot com> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|UNCONFIRMED                 |RESOLVED
         Resolution|                            |INVALID

--- Comment #11 from Timothy J Giese <timothyjgiese at gmail dot com> 2011-07-05 21:05:54 UTC ---
These were some useful explanations - thanks gang.

I'm going to go ahead and close this because it seems clear now that what g++
is doing is not incorrect.

To close this off, I'm going to show a work-around for the original minimal
test case, just in case someone lands here from a search engine with a similar
problem:



#include <iostream>

template <class T,class U>  struct TypeMatch      { static bool const value =
false; };
template <class T>          struct TypeMatch<T,T> { static bool const value =
true;  };

// Create 2 functions with different names
struct S { typedef int iterator; };
template <class T,class U> void FU  (typename T::iterator,U  ) { std::cout <<
"FU"   << std::endl; };
template <class T>         void Fint(typename T::iterator,int) { std::cout <<
"Fint" << std::endl; };

// Create a selector function that acts like an overload
template <class T,class U> inline void F( typename T::iterator i, U u )
{
  if ( TypeMatch<int,U>::value ) { Fint<T>(i,u); }
  else                           { FU<T,U>(i,u); };
};

// Disadvantage = every new "overload" needs to be inserted into F
// However; I won't run into this with my immediate use-case, so I'm not going
to complain too hard


int main()
{
  S::iterator i(42);
  F<S>(i,1);      // Compiles OK; prints "Fint"
  F<S>(i,true);   // Compiles OK; prints "FU"
  return 0;
};



This work-around compiles fine on g++ 4.6.0.