Inherited const when you need to mutate

[Walter Bright]

On 7/10/2012 4:16 PM, Timon Gehr wrote:
> Const is stronger than what is required to bridge the gap between
> mutable and immutable. It guarantees that a reference cannot be used to
> mutate the receiver regardless of whether or not the receiver is
> immutable underneath. That is unnecessary as far as immutable is
> concerned. It only needs to guarantee that the receiver does not change
> if it is immutable underneath.

If you have a const function that accepts both mutable and immutable args, then 
that function *by definition* cannot tell if it received mutable or immutable args.

Furthermore, a const function is saying it will not change, even if mutable data 
is passed to it.

Everything falls apart once you allow "logical const" in. You'll be in the same 
boat as C++ const, which is faith-based programming rather than checkable 
programming.