const as default for variables

[deadalnix via Digitalmars-d]

On Tuesday, 17 March 2015 at 13:55:36 UTC, Dejan Lekic wrote:
> I definitely think this is a good idea. And if someone wants 
> mutable variable, we simply use proposed 'var' storage class.
>
> Brilliant!

This is going to break pretty much all the code that use auto.

The benefice for the compiler is hypothetical. Walter is right 
when mentioning that is can remove some refcount boilerplate, 
which is right but, we have no idea how much, and how good the 
compiler would be at recognizing them. With existing languag 
feature, the compiler CANNOT leverage this change for 
optimization.

I'd consider this if it was from scratch, but in the current 
state of affair, it is a change that does not pay for itself.

Switching to @safe by default for instance will break less code 
while providing more.