bug#70597: Problem in pcase-let?

[Stefan Monnier]

> Pattern matchers do ... pattern matching.

`pcase` is a pattern matcher.
`pcase-let` is not: it performs "destructuring bindings".

If you want to test if a pattern matches, then you want to use `pcase`
or `pcase-exhaustive`, and not `pcase-let`.

If you want a "one-branch `pcase-exhaustive` with a let-style notation",
we could add such a thing of course, but I'd first like to see some
evidence that it's useful in practice.


        Stefan