bug#31350: 27.0; `pcase' message: "Redundant pcase pattern"

[Michael Heerdegen <michael_heerdegen@web.de>]

Lars Ingebrigtsen <larsi@gnus.org> writes:

> > These are the two clauses in question:
> >
> >  (`,a `(not,a))
> >  ((and a (guard (not recursivep))) `(not ,a))
>
> Can you post a complete test case that demonstrates the problem?

Well, when we compile something like

(defun test (foo recursivep)
  (pcase foo
    (a `(not ,a))
    ((and a (guard recursivep))
     `(not ,a))))

the message Drew means says

  Redundant pcase pattern: (and a (guard recursivep))

I'm happy with that, I think it tells anything I need to know.  I'm not
happy about the fact that I missed the `message' because it's only a
message and I only see it when I look into the *Messages* buffer because
it's overwritten very soon in the echo area.

The compiler log only shows

Compiling file /home/micha/today/pctest.el at Sun Oct  4 00:44:51 2020
pctest.el:46:1: Warning: Unused lexical argument `recursivep'

which is confusing if you missed the message about the redundant
pattern.

Michael.