isaac lewis <isaac.b.lewis@gmail.com> schrieb am So., 11. Juni 2017 um
09:24 Uhr:

> If my understanding is correct, the functions (lambda (&rest) t)
> and (lambda () t) should behave similarly.
>

From where did you get this understanding? The Elisp manual says about
&rest:
"To specify a list of zero or more extra arguments, include the
keyword &rest before one final argument."
and
"The keyword &rest (which must be followed by a single
argument name) indicates that any number of arguments can follow."
i.e. the parameter after &rest isn't optional.