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.