type function U[1] and U(*)[1] SFINAE issue

Hello, I just hit a strange problem regarding SFINAE. The following code
causes compile error (void cannot be array element type), I thought
SFINA should match test(...) version instead and not issue any error.

If I replace U[1] with U(*)[1], then the code compiles again. I couldn't
make the sense out of it. What's the magic with (*)? Note that
function<int>::yes returns correct result 0 even with U[1].

Please help me out.

Fei

#include <iostream>
using namespace std;

template <typename T>
struct function{

     template <typename U> static char test(...);
     template <typename U> static char (&test(U[1]))[2];

     enum { yes = (sizeof(function<T>::test<T>(0)) == 1) };
};

int main(){

     cout << "int: " << function<int>::yes << endl;
     cout << "void: " << function<void>::yes << endl;
     // function
     cout << "void(): " << function<void()>::yes << endl;
     // function ptr
     cout << "void(*)(): " << function<void(*)()>::yes << endl;
}