Tags: patch
X-Debbugs-Cc: Stefan Monnier <monnier@iro.umontreal.ca>

After evaluating (add-hook 'occur-hook 'occur-rename-buffer)
then selecting a region, and running 'M-x occur' with any string
in the active region, signals the error:

  (wrong-type-argument bufferp #<overlay from 1 to 72 in *scratch*>)

It seems the attached patch is the right way to fix this.

Also Cc:ing Stefan with a question about occur--garbage-collect-revert-args:
trying to revert the Occur buffer created from an active region
removes the source buffer name from the Occur buffer name.
For example, (after applying the attached patch) 'M-x occur'
on the active region in *scratch* creates the buffer *Occur: *scratch**.

But reverting the Occur buffer with 'g' removes the *scratch* buffer name,
and renames the Occur buffer to *Occur: *.

This is because of two lines in occur-1:

          (occur--garbage-collect-revert-args)
	  (setq occur-revert-arguments (list regexp nlines bufs))

where occur--garbage-collect-revert-args deletes the overlay
with the buffer name *scratch*, and later occur-rename-buffer
can't get the original buffer name from occur-revert-arguments.
And I don't know how to fix this.