how to properly overload function templates?

[Trass3r]

I stumbled across this while playing with operator overloading. Since they  
are now function templates, this becomes an issue.

struct Vector2(T)
{
	T x;
	T y;

	/// element-wise operations, +, -,
	Vector2 opBinary(string op)(ref Vector2 v)
	{
		mixin("return Vector2!(T)( cast(T)(x " ~ op ~ " v.x), cast(T)(y " ~ op ~  
" v.y) );");
	}

	/// operation with scalar
	Vector2 opBinary(string op)(int i)
	{
		mixin("return Vector2!(T) ( cast(T)(x " ~ op ~ " i), cast(T)(y " ~ op ~  
" i) );");
	}
}

This yields:
template instance opBinary!("+") matches more than one template declaration

Of course this can be circumvented by using
opBinary(string op, U:Vector2)(U v)
opBinary(string op, U:int)(U v)


But is this how it's supposed to be done? Couldn't the compiler detect  
that itself?