Why do immutable variables need reference counting?

[ag0aep6g]

On 17.04.22 15:06, wjoe wrote:
> On the matter of undefined behavior. Technically a program is in 
> undefined behavior land after throwing an error, thus every unittest 
> that continues after assertThrown is therefore nonsense code, is it not ?

Yes.

Failing asserts are a messy part of the language. They are supposed to be:

1) not catchable, because they indicate a bug in the program;
2) catchable in order to be testable;
3) assumed impossible for optimization purposes.

Those goals are at odds with each other, and I don't think the spec 
manages to consolidate them.

But mutating `immutable` data is not messy. It's simply not allowed.