Don't try to pretty-print non-lists as binding list

* lisp/emacs-lisp/pp.el (pp--format-definition): Ensure that what we try
to print as a list of bindings has an appropriate format.  This avoids
raising an error for SEXPs like (let X Y) inside `pcase' forms where our
heuristic expects a binding list in the X position.

(cherry picked from commit 3580dc155c3c9f48fb1b7855b4d858eec3948dfb)

diff --git a/lisp/emacs-lisp/pp.el b/lisp/emacs-lisp/pp.el
index 0ac74977d0b08d5754c75fa4edfb41afd5880545..0b4a6187e1dfa9b0a348058c72db739d060a06e6 100644 (file)
--- a/lisp/emacs-lisp/pp.el
+++ b/lisp/emacs-lisp/pp.el
@@ -578,7 +578,8 @@ the bounds of a region containing Lisp code to pretty-print."
     (unless (consp edebug)
       (setq edebug nil))
     (if (and (consp (car edebug))
-             (eq (caar edebug) '&rest))
+             (eq (caar edebug) '&rest)
+             (proper-list-p (car sexp)))
         (pp--insert-binding (pop sexp))
       (if (null (car sexp))
           (insert "()")