> Do you expect some other behavior in such case?

No, just saying this stuff is implicit and thus hard to read. More so the allocation on indexing assignment. and keeping things which shouldn't be mutated const wasn't a problem at all.

> and keeping things which shouldn't be mutated const wasn't a problem at all.

As soon as datastructures become more complicated and more interconnected, it's not clear anymore what const should even mean (issues are similar as with deep vs shallow copies, how do you even draw the lines, where are the objects?).

And the major philosophical flaw in the const vs. non-const distinction is that to make a strict separation you have to move everything mutable into constructor calls (for the most part, not getting more into the weeds of C++). Which is very awkward, it's a real tradeoff you need to be aware of. I realized only after playing these games for a long time what a waste of time it is and how much complexity it creates.