On Tuesday, 16 February 2016 at 07:46:11 UTC, w0rp wrote:
I think if we could avoid putting head const in the language, we'd be better off. If you ever really, really need to mutate something inside a const type, you can cast away const. It will rightly look ugly, and the compiler can complain that it's not @safe.
Actually, in D, it's undefined behavior to cast away const and mutate. D's const is supposed to guarantee that the data cannot be mutated via a const reference to the data. Given that very few optimizations can be made based solely on const (and I'm not sure that the compiler currently does any of them), it will almost certainly work as long as the underlying data is mutable rather than immutable, but it _is_ undefined behavior, and you're violating the guarantees that the type system provides when you go around it like that.
- Jonathan M Davis
