Why does it not compile?

[Morlan]

The program below compiles. Clearly the "if" constraints in my original example
are causing trouble. It seems like a bug to me.

import std.stdio;

void Foo(T:T*)(T arg) {
  writeln("arg of Foo:", arg, typeid(T));
}
void main() {
  Foo!(long*)(54);
}