During test of the preceding named references patch I noticed that the
output of (for example)
    typeset -pam \*
was not restricted to just array parameters.  Other flags than -a
produced even stranger results.

It turns out that combining -p and -m with other flags would actually
apply changes to the types of some parameters, e.g., converting things
to/from arrays or adding integer or float attributes.  This has been
the case for a very long time (possibly since inception).

Attached patch attempts to impose sanity on this.  It should be
applied after 51430 but I'll wait a bit to push it since the use case
plainly isn't a common one.