Why compile error with enable_if

Question

Why this does not compile with gcc48 and clang32?

#include 

template  
struct S {

    template 
    typename         


        

Answer 1

For this case you could think about not using enable_if at all. It is posible to simply specialise f:

template  
struct S {
    template int f(T t);
};

template
template
int S::f(T t) { return 2; }

template<>
template
int S<1>::f(T t) { return 1; }

int main() {
    S<1> s1;
    return s1.f(99);
}