bug#64404: 30.0.50; condition-case-unless-debug mishandles :success

[Eli Zaretskii]

> Cc: Mattias Engdegård <mattias.engdegard@gmail.com>
> Date: Sat, 01 Jul 2023 20:32:10 +0100
> From:  Basil Contovounesios via "Bug reports for GNU Emacs,
>  the Swiss army knife of text editors" <bug-gnu-emacs@gnu.org>
> 
> 0. emacs -Q
> 1. M-: (condition-case nil 1 (:success 2)) RET
>    => 2
> 2. M-: (condition-case-unless-debug nil 1 (:success 2)) RET
>    => 1
> 
> This can easily be fixed in condition-case-unless-debug, and worked
> around by using explicit 'debug' with condition-case, but I was
> wondering if we want to do anything differently in
> internal_lisp_condition_case or the byte-compiler (e.g. new warning)
> instead?

Adding Stefan to the discussion.