mutable destructor? WAT???

[Dicebot via Digitalmars-d-learn]

And this segfaults (on Linux):

void main() @safe
{
      auto s = const(S)("abcd");
      foo(s);
}

I'd call it a clear bug. Most obvious fix would be to require 
const destructor if non-default destructor is present AND 
immutable/const instance is attempted to be created.