Compiler error in gcc3+ involving template template parameter and default parameters

[Edward Diener]

The fairly simple code below, involving template template parameters and 
default parameters compiles with an error in gcc3+ compilers but 
compiles without error in gcc4+ and up, and with other conforming compilers:

"template<class T>
struct eval;

template
   <
   template<class> class F,
   class P1
   >
struct eval<F<P1> > :
   F<typename P1::type>{};

template
   <
   template<class,class> class F,
   class P1,
   class P2
   >
struct eval<F<P1,P2> > :
   F<typename P1::type,typename P2::type>{};

struct noparam
   {
   typedef noparam type;
   };

template
   <
   class T,
   class P = noparam
   >
struct ptmf
   {
   typedef int type;
   };

template
   <
   class T,
   class P = noparam
   >
struct tkf :
   eval<ptmf<T,P> >{};

template <class T>
struct ATemplate
   {
   typedef T type;
   };

int main()
   {
   tkf<ATemplate<int> > aVar;
   return 0;
   }"

The command line in MingW on Windows is:

"g++" -ftemplate-depth-128 -O0 -fno-inline -Wall -g -c "TestGcc3.cpp"

The error message is:

"TestGcc3.cpp: In instantiation of `tkf<ATemplate<int>, nopar
am>':
TestGcc3.cpp:52:   instantiated from here
TestGcc3.cpp:42: error: ambiguous class template instantiatio
n for `struct eval<ptmf<ATemplate<int>, noparam> >'
TestGcc3.cpp:19: error: candidates are: struct eval<F<P1, P2>
  >
TestGcc3.cpp:10: error:                 struct eval<F<P1> >
TestGcc3.cpp:42: error: invalid use of undefined type `struct
  eval<ptmf<ATemplate<int>, noparam> >'
TestGcc3.cpp:2: error: declaration of `struct eval<ptmf<ATemp
late<int>, noparam> >'
TestGcc3.cpp: In function `int main()':
TestGcc3.cpp:52: warning: unused variable 'aVar'"

I am looking for a workaround for gcc3+ compilers which does not involve 
getting rid of the default parameters. If I remove the default 
parameters, and change the instantiation of tkf to:

tkf<ATemplate<int>,ATemplate<int> > aVar;

the compile is successful and there is no error. This is of course a 
very simplified illustration of much more complicated code and 
maintaining default parameters within the more complicated situation is 
a much cleaner syntax than the alternative.

If you ask why I am trying to get this to work under gcc3 it is because 
I am creating a library for Boost and would like to still support gcc3+ 
with my library.