Something goes wrong with range and sort?

[Andrea Fontana]

	string[] test_filter(string[] words)
	{
		static blackList =
		[
			"d", "c", "e", "a", "è", "é", "e"
		].sort();
		
		return words.filter!((a) => 
!blackList.assumeSorted.contains(a)).array;
	}

	test_filter(["a", "b", "test", "hello"]).writeln;


This code crash! It's just a useless trimmed-down version of a 
more complex code, just to show you the bug.

If you remove accented letters from "blacklist" array it works 
fine. Why?