Error Compiling with -debug swtich

[Jordan Wilson via Digitalmars-d-learn]

Hello,

Just wondering why compiling the following fails with the -debug 
switch, but appears to compile and execute fine without it:

import std.stdio;
import std.algorithm;
import std.container;

int main(string[] args) {
    Array!string letters = ["b","a","c"];
    sort(letters[]);
    writeln (letters[]); // ["a","b","c"]
    return 0;
}

With the -debug switch, I get:
src\phobos\std\range\package.d(7180): Error: 
'std.range.SortedRange!(RangeT!(Array!string), "a < 
b").SortedRange.dbgVerifySorted' is not nothrow
src\phobos\std\algorithm\sorting.d(982): Error: template instance 
std.range.assumeSorted!("a < b", RangeT!(Array!string)) error 
instantiating

Without the switch, everything seems to work fine...(I'm using 
DMD 2.068.0)

Thanks,

Jordan