Which language constructs could be done as a library if we accept some breaking changes?

[user1234]

On Monday, 29 November 2021 at 12:51:47 UTC, Ola Fosheim Grøstad 
wrote:
> On Monday, 29 November 2021 at 12:30:42 UTC, user1234 wrote:
>> static casts, devirtualization, are reasons for built-in
> Also, since it would be a standard library construct a good 
> compiler could have a special path for those. So it should 
> remain the same.

If there must be a special path then it's already a failed 
library solution, not to say a lie. You make think to the user 
that classes is a library thing but it's not.