bug#65209: 30.0.50; Unexpected behaviour of setq-local

[Eli Zaretskii]

> From: Michael Heerdegen <michael_heerdegen@web.de>
> Cc: 65209@debbugs.gnu.org,  gerd.moellmann@gmail.com,  
> monnier@iro.umontreal.ca
> Date: Wed, 23 Aug 2023 05:47:18 +0200
> 
> Ok - I'm not good at writing documentation.  As a start, do you think
> that it's possible to create a good addition to the manual out of this
> stub?
> 
> 
> | The following example demonstrates which binding is "seen" when
> | let-binding and buffer-local variables are combined:
> |
> | (defvar var :default)
> |
> | (with-temp-buffer
> |   (let ((var :let-bound))
> |     var                            ; --> :let-bound
> |     (setq-local var :buffer-local)
> |     var                            ; --> :buffer-local
> |     (with-temp-buffer var))        ; --> :let-bound
> |   var                              ; --> :buffer-local
> |   (with-temp-buffer var))          ; --> :default
> |
> |
> | A lexical variable always refers to its lexical binding even when
> | a buffer-local variable of the same name exists:
> |
> | (let ((lvar :lexical))
> |   (setq-local lvar :local)
> |   lvar                           ; --> :lexical
> |   (symbol-value 'lvar))          ; --> :local

Yes, but it has to be described in English, not (only) in Lisp.

(TBH, the first one is almost self-evident, and I find nothing
surprising or unexpected in it.)

> I would not suggest such an addition if I would not have missed that
> kind of information in the manual.

Which part(s) did you miss?  AFAIU, the behavior with dynamic
variables is described in very clear terms which make the first
example completely described.