static void sfunc() { }
int x;
void func() { x++; }
int delegate() dg;
assert(isDelegate!dg);
assert(isDelegate!(int delegate()));
assert(isDelegate!(typeof(&func)));
int function() fp;
assert(!isDelegate!fp);
assert(!isDelegate!(int function()));
assert(!isDelegate!(typeof(&sfunc)));
Detect whether symbol or type T is a delegate.