I'm not sure if this is a bug, but the function map-put does not change its
argument MAP if the map is an alist and the key is not found.

For example, the following code returns "value" as expected:

(require 'map)
(let ((m (make-hash-table)))
  (map-put m 'key "value")
  (map-elt m 'key))

If I replace m by an alist, then the following code returns nil.
I expected it returned "value" as above.

(let ((m nil))
  (map-put m 'key "value")
  (map-elt m 'key))

By expanding map-put, I found that it returns a new list if "m" is a list
and
the key is not in "m".

Best regards,
Sho Takemori

In GNU Emacs 25.0.92.1 (x86_64-unknown-linux-gnu, GTK+ Version 3.16.7)
 of 2016-03-24 built on K430-Ubuntu
Repository revision: c0165ea4d6ecf81db6728782c7322c311ee0a783
Windowing system distributor 'The X.Org Foundation', version 11.0.11702000
System Description: Ubuntu 15.10

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Mark set
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