Possible class creation optimization

[A5rocks]

Was looking at the CPython issue tracker and noticed https://github.com/python/cpython/issues/100930

It looks like attrs doesn't do this either. I don't know if this is wanted or whether this can work with linecache.

[hynek]

It's a very specific optimization that only works for a narrow class of problems. I've been watching it (it originates in this forum thread) and I'm not sure the complexity is really worth it – hasn't any weird side-effects we aren't expecting, yet.