Re: How to avoid compiler warning `unused lexical variable' for `dolist' or `dotimes'?

[Philipp Stephani]

Am Fr., 8. Jan. 2021 um 14:14 Uhr schrieb <tomas@tuxteam.de>:

> Fixing the macro definition is a bit more attractive (e.g.
> it could try to decide whether RESULT depends on i and
> not generate that let-binding if not), but I can't decide
> right now whether that involves the halting problem or not.

Certainly not, since that's what the byte compiler is doing. It's just
a lexical walk through the code after macroexpansion.

(require 'cconv)
(let ((env '((VAR nil nil nil nil))))
  (cconv-analyze-form (macroexpand-all RESULT-FORM t) env)
  (cadr (assq VAR env)))

Should return t if VAR is used in RESULT-FORM.

But then, I don't know whether that's worth it or not. Alternatively,
you could add an (ignore VAR) to the macro expansion of the result
form so that cconv treats the variable as used.