Subject: bug#25558: Spurious warnings with variables mentioned only pcase guard patterns

From: Clément Pit--Claudel <[email-masked]>
Date: Fri, 27 Jan 2017 19:14:54 -0500

The following causes a warning (unused variable 'b'):

  (pcase '(1 2) ((and `(,a ,b) (guard (equal a b))) a))

This is due to pcase let-binding 'a' twice; once around the guard test ('(equal a b)'), and once around the body ('a').