bug#51695: 29.0.50; lexical scope closure, interactive spec byte compiler warnings/usage issue

[Emanuel Berg via "Bug reports for GNU Emacs, the Swiss army knife of text editors" <bug-gnu-emacs@gnu.org>]

>> #+begin_src emacs-lisp
>> (let* ((data-item 1)
>>        (more-data 2))
>>   (defalias 'echo-data--interactive
>>     (lambda ()
>>       (list (read-number "number: " (or data-item more-data)))))
>>   (declare-function echo-data--interactive test) ;defun was not top-level
>>   (defun echo-data (&optional data)
>>     (interactive (echo-data--interactive))
>>     (message "data: %s" (or data data-item)) ))
>> #+end_src
>
> Thanks, I wrote this to illustrate the situation but
> interesting nonetheless, I don't think I've seen `defalias'
> to a `lambda' before and also didn't think of putting
> `declare-function' within the `let' body ... practical.

It works.

Both the aliases and the functions have to be
`declare-function'ed for the byte compiler.

`defalias' and `lambda' BTW, isn't that an anonymous function
with a name ... maybe an ordinary function makes more sense
there, especially since `declare-function' has to be used?

Or why a lambda?

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