static assert / static if

[Lionello Lunesu]

I'm confused:

template factorial(int n)
{
	static assert(n>0);
	static if (n == 1)
		const factorial = 1;
	else
		const factorial =
			n * factorial!(n-1);
}

int main()
{
	return factorial!(0);
}

The static assert doesn't trip. If I remove the recursion, it works 
fine, but with it the compiler stops with:

ct.d(8): template instance ct.factorial!(-3078) recursive expansion

At first I thought that the template is instantiated before the assert 
is tested, but the static if IS tested before recursion, so why isn't 
the assert? Is it a bug?

L.