Re: case-table functions clobbering extra slots

[Richard Stallman]

    Things like set-case-syntax-pair clobber the extra slots of the case
    table.  Is there a good reason for that?  It isn't documented.

The reason was documented in some of the previous commands in this file.
I will copy these comments into the functions that didn't have them.

    It defeats treating cases where there isn't one-to-one correspondence
    between upper and lower (which is even mentioned as a possibility in
    (elisp)Case Tables).

If that is true, it could be because automatically recomputing the
three derived tables does not know how to handle this case correctly.
Is that it?

Can you show the code that would handle this case correctly?