CRTP nullary in derived conflicts with unary in base

[er ci]

Could someone please shed light on the cause of the error below, and
perhaps hint at a solution? I used Mac OSX 10.6 -- GCC 4.2. Thanks.

template<typename D>
struct crtp{

template<typename T>
void fun(T const& x)const{
static_cast<D const&>(*this).template impl<T>(x);
}

};

struct foo : crtp<foo>{

foo(){}

// uncommenting causes compile error
// no matching function for call to 'foo::fun(int)'
// candidates are: void foo::fun() const
// void fun()const{}

template<typename T>
void impl(T const& x)const{}

};

int main (int argc, char * const argv[]) {

foo f;
f.fun( 1 );
}

 

[SG]

Could someone please shed light on the cause of the error below,
and perhaps hint at a solution?

See C++ FAQ Lite 23.8 and 23.9.

Cheers!
SG