This is correct D2 code, and it gives no error messages:

void foo(T)(const ref T[] a) {}
void bar(in int[] b) {
    foo(b);
}
void main() {}



This is wrong D2 code (I have replaced "const ref" with "ref"):


void foo(T)(ref T[] a) {}
void bar(in int[] b) {
    foo(b);
}
void main() {}


DMD 2.059 gives this error message:

temp.d(1): Error: template temp.foo(T) cannot deduce template function from argument types !()(const(int[]))

In this case I'd like a better error message.