Template mixin can not introduce overloads

[Tofu Ninja via Digitalmars-d-learn]

Is this intended or is it a bug?

void main(string[] args)
{
	Test a;
	a.foo(5); // Fails to compile
}

struct Test
{
	mixin testMix;
	void foo(string y){}
}

mixin template testMix()
{
	void foo(int x){}
}