This code causes an Internal Error

[Sterling Christensen]

// --- Begin test.d ---
uint octal (char[] s)
{
	ubyte shift = (s.length - 1) * 3;
	uint answer = 0;
	
	for (int i = 0; i < s.length; i++)
	{
		answer += (s[i] - '0') << shift;
		shift -= 3;
	}
	
	return answer;
}

void main ()
{
	assert (octal("0777") == 0777);
}
// --- End of test.d ---

dmd -O test.d
Internal error: ../ztc/cgcod.c 1677

dmd v0.162

It compiles if you:
1. don't optimize (no -O)
2. change "return answer" to "return 0" on line 12
3. change the 3 on line 3 to 1, 2, 4, 7, or 8... 5, 6, 9, and 10 still  
cause the internal error. (I didn't try higher than 10)
4. Change "ubyte shift" to "uint shift"
5. comment out the for or the answer+=
6. change the for to a foreach