Casting away const and invariant

[Janice Caron]

> If casting away const in D always involves undefined behavior
> (and not only when the resulting object is modified) then it
> should certainly be detected and disallowed at compile time.

Of course.

However, according to Walter, I quote: "Because a static type system
can be a straitjacket, there needs to be a way to circumvent it for
special cases."

and... "The ability to cast away invariant-correctness is necessary in
some cases where the static typing is incorrect and not fixable, such
as when referencing code in a library one cannot change. Casting is,
as always, a blunt and effective instrument, and when using it to cast
away invariant-correctness, one must assume the responsibility to
ensure the invariantness of the data, as the compiler will no longer
be able to statically do so."

Both of those quotes indicate that D requires a way to do the
unthinkable. Therefore, as stated above, and (somewhat better) on
another thread, I argue that the solution is to disallow it - except
with some special, unambiguous syntax, which makes plain you are
deliberately breaking the rules. Preferably something greppable. See
other thread.