Some strange parameter deduction problems in opOpAssign and opBinary

[Ivan Agafonov]

There are 3 separated versions of opOpAssign
first version must be the same as the second for Vec!(sometype, 4)
why it doesn't work?

Simplified code:

struct Vec(T, uint size)
{
	this(T rhs) { array[] = rhs; }
	
	// It doesn't work but compiles
	ref Vec!(T, size) opOpAssign(string op) (Vec!(T, size) rhs)
	{
		mixin("array[] "~op~"= rhs.array[];");
		return this;
	}
	
	// but it work's
	ref Vec!(T, 4) opOpAssign(string op) (Vec!(T, 4) rhs)
	{
		mixin("array[] "~op~"= rhs.array[];");
		return this;
	}
	
	// and this work;s
	ref Vec!(T, size) opAddAssign(Vec!(T, size) rhs)
	{
		array[] += rhs.array[];
		return this;
	}
	
	T[size] array = 0;
}

int main()
{
	auto z = Vec!(float, 4)(5.0f);
	z += z;
	writeln(z);
	return 0;
}