Template specialization, default args, typedef and an internal compiler error

Hello,

I have a piece of code who don't compile in Visual C++ 2005 and I
suspect a bug of the compiler since it seems to be valid code (and is
compiled without complain by at least two other compilers):

class A {};

class B {};

// template function
template<class T>
T foo(B const &b, A const &a = A())
{
     return T();
}

// specialization of the function
template<>
B foo<B>(B const &b, A const &a)
{
     return B();
}

int main()
{
    B b;
    foo<B>(b); // << no problem

    typedef B aliasB;
    foo<aliasB>(b); // << don't compile
}

The error reads:
--------------
error C2440: 'default argument' : cannot convert from 'const A *__w64 '
to 'const A &'
         Reason: cannot convert from 'const A *__w64 ' to 'const A'
         No constructor could take the source type, or constructor
overload resolution was ambiguous
--------------

More over, if I remove "const &" for the parameter "a" of both function
foo, I obtain an internal compiler error at the same line:

--------------
fatal error C1001: An internal error has occurred in the compiler.
(compiler file 'f:\RTM\VCTOOLS\Compiler\CxxFE\sl\P1\C\toil.c', line 7366)
--------------

This occurs in "debug" as well as in "release" mode.

Is this a known bug and what are the possible workarounds?

Thanks.

--
Cyrille