On 2/16/2016 11:29 AM, Marc Schütz wrote:
For example, it's always possible to use a global mutable associative array to store additional data connected with an immutable or const object (ignoring purity issues for the moment). That's safe because from the outside, there's no observable change to the state of the object itself, and the global AA's type (shared/thread-local) prevents race conditions.
The trouble with that is you're relying on the programmer to ensure correctness. It'll revert D to C++ "trust the programmer" semantics.
Furthermore, with the current mechanical guarantee of immutability, it opens up the possibility of relying on such beyond merely observable behavior - such as immutable data being placed in ROM, or special GC semantics.
