Struct assignment, possible DMD bug?

[ixid]

This behaviour seems inconsistent and unintuitive:

void main() {
	int[3] a = [1,2,3];
	a = [4, a[0], 6];

	struct S {
		int a, b, c;
	}

	S s = S(1,2,3);
	s = S(4, s.a, 6);

	assert(a == [4,1,6]);
	assert(s == S(4,4,6));
}

Setting the struct writes s.a before evaluating it while the 
reverse is true of the array assignment. Using DMD 2.0.60. GDC 
does what I'd expect and gives both as 4,1,6.