front(char[]) is not assignable, it's not a reference. If you look at the contraint,
"range.front = value "
must be compilable. front(char[]) is not assignable because it decodes an undetermined amount of bytes.
That said there's no valid reason to disallow to fill with a char since it can fill exactly array.length times the array.
Comment #2 by niklas.volcz — 2016-09-22T12:32:29Z
Was bitten by this issue today. Can we at least improve the error message?