X-Debbugs-Cc: Nicolas Petton <nicolas@petton.fr>, Stefan Monnier <monnier@iro.umontreal.ca>
Tags: patch

The attached patch for map.el and seq.el was initially motivated by the
fact that (map--plist-p '(nil 1)) currently returns nil, whereas I'd
expect an alist to begin with a cons.

Along the way I noticed some other inconsistencies, such as map-do
returning non-nil for alists, and the use of 5-arg alist-get when map.el
expects Emacs 25; and edge cases such as an OBOE on arrays in
map-delete.

Throughout the patch I assume that cl-defgeneric is generally preferred
over map--dispatch, except where some aspect of the latter can't be
matched by the former, e.g. the use of advertised-calling-convention.

WDYT?

Thanks,

-- 
Basil