bug#16935: 24.3.50; when tab-completing in 'M-x' : "Wrong type argument: numberp, nil"

[Glenn Morris]

Bastien wrote:

> The error originated here:
> http://git.savannah.gnu.org/cgit/emacs.git/commit/?id=66c5fecc
>
> The commit makes `base-size' optional, so we need to ensure it
> falls back to 0 instead of nil.

Making an argument optional couldn't cause this. It was the other part
of that commit, just now reverted.