'Double free' even with @disabled this(this)

[Maurice]

Hey,

I'm trying to use a struct for RAII (like C++'s unique_ptr), so i 
@disabled this(this). However, it's still getting copied somehow:

struct A {
	int some_resource = 0;
	~this() { if (some_resource) writeln("Freeing resource."); }
	@disable this(this); // Prevent copying
}

struct B {
	A a;
	alias a this;
}

void main() {
	B b;
	b.some_resource = 100;
	A a = move(b);
}

The above code prints 'Freeing resource.' twice!

See it in action on http://dpaste.dzfl.pl/6461df03

I guess the first one is from the temporary B that move(b) gives. 
However, that temporary should be moved into a and then left in 
B.init state, but that doesn't happen.

Is this a bug?