must either both be scalars or both be lists. Otherwise Perl won't
know which context to supply to the right side.
+=item Assigning to negative offset in vec
+
+(F) The second argument to vec() must refer to an actual element of
+the string if you wish to assign to it.
+
=item Attempt to bless into a reference
(F) The CLASSNAME argument to the bless() operator is expected to be