Issue: DECLARE-ARRAY-TYPE-ELEMENT-REFERENCES

[Jon L White <jonl@lucid.com>]

re:     But if all that Dan wanted to say was that the array
        references were assumed to satisfy the *upgrade* of the declared type,
        then there would be no problem (with that part).
    
    Sorry, but that's exactly the opposite of what I meant.  If I declare
    an array, FOO, to be (SIGNED-BYTE 5), within the scope of that
    definition I'm saying that expect references to that array to be
    equivalent to:
        (THE (SIGNED-BYTE 5) (AREF FOO X))
    No matter what the array was upgraded to.  

Yea, that's what I thought you meant, and that's what I think is
inconsistent with the "unification" in issue ARRAY-ELEMENT-TYPE-SEMANTICS.

re: Actually, your name got put in support because of an early message of
    yours (which I finally found) in the ARRAY-ELEMENT-TYPE-SEMANTICS
    discussion.  I'll be happy to remove your name if we now disagree.

I fear that my very first reading of DECLARE-ARRAY-TYPE-ELEMENT-REFERENCES
was too hasty, and I incorrectly thought it was subsumed by
ARRAY-ELEMENT-TYPE-SEMANTICS.  I'm sure I recanted that apostasy in
later mail.


re: As I've said before, I support a strict type checking mode for all
    Common Lisp compilers.  However I now suspect that it's too late (and
    maybe too experimental) to get in this version of the standard.  I
    said I'd write up a proposal for it at the cleanup meeting last
    October, but was later talked out of doing so.

Why?  [i.e., Why did you get "talked out of doing so"?]  I remember 
discussing this with you at length during the Palo Alto meeting in
March 1988 and likeing it very much.  However -- I hasten to point
out -- it would help not to confuse this issue with the very limited
scope of DECLARE-ARRAY-TYPE-ELEMENT-REFERENCES, which has it's own
peculiar problems related to "upgrading".


-- JonL --