Sort of a meta-bug.  Large portions of Phobos are relying on Bug 3534 to allow const/immutable arrays to be used as ranges, because this bug allows calling popFront() and popBack() on them.  Example from std.string:

sizediff_t
indexOf(Char1, Char2)(in Char1[] s, in Char2[] sub,
        CaseSensitive cs = CaseSensitive.yes)
{
    // Somewhere in the function body:
    immutable result = s.length - std.algorithm.find(s, sub).length;
}

This code doesn't work if std.array.popFront() is modified to not be callable on const/immutable arrays.

This is just one example.  There are several more across much of Phobos.