New type specifier?

[Rob MacLachlan <RAM@C.CS.CMU.EDU>]

    On second thought, it isn't true that the call to FROB-FOO would
be replaced with a call to error, since it is possible that FROB-FOO
may not return.  This doesn't reduce the usefulness of getting a
warning, though.  Lisp's dynamic typing makes it very difficult to
prove anything erroneous, but there are many code sequences which are
unreasonable.  Compiler warnings are for flagging code which is
probably not what you want.  If you write lots of declarations, you
give the compiler a better idea of what you want, so it can give
better warnings.  VOID declarations give a useful increment in
specifying what I want.  Judging from various discussions of (VALUES),
I think that there is demand for a way to declare "procedures" in
Common Lisp.

  Rob