bug#49809: [PATCH] Add macro 'pcase-setq'

[Michael Heerdegen]

Stefan Monnier <monnier@iro.umontreal.ca> writes:

> I'd expect a behavior like that of `pcase-let`, instead.

I don't recall why it was not achievable to make `pcase-let' reliably
error for non-matching patterns.  Would that be possible for
`pcase-setq'?

(What for example would happen if we just wrapped each PAT inside

  (or PAT (guard (error "pcase-setq: PAT doesn't match")))

?)

Michael.