On 07/11/2012 12:39 AM, Walter Bright wrote:
On 7/10/2012 3:13 PM, H. S. Teoh wrote:
I don't think they were rushed. There's been a push for making druntime
and Phobos const-correct for a while now. I don't think this change is a
_mistake_ per se, but it does expose a flaw in the language: const is
too limited in scope, and we need something else to fill in for use
cases where const isn't good enough.
There's a gigantic problem with logical const. It is completely
unenforceable - it is documentation only. All the reasoning and
mechanical guarantees that come with const, immutable, and purity fall
apart.
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.
