Subject: bug#6878: bool-vectors of length 0 signal error when aref/aset the 0th element

From: Stefan Monnier <[email-masked]>
Date: Thu, 19 Aug 2010 16:47:36 +0200

>> Maybe, but this is not what the manual has to say of the particular type of
>> array that is a bool-vector, again (note the "must"):
>> ,---- (info "(elisp)Bool-Vector Type")
>> | "A "bool-vector" is a one-dimensional array of elements that must be `t'
>> | or `nil'."
> All elements of (make-bool-vector 0 t) are either t or nil.

Indeed, this is trivially (and vacuously) true.  Actually, we can even
say that all elements of a 0-length vector (bool or not) are both nil
and t at the same time.

        Stefan