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question about subtypep

    Date: Monday, 25 August 1986  14:02-EDT
    From: David A. Moon <Moon at STONY-BROOK.SCRC.Symbolics.COM>

        Date: Thu, 14 Aug 1986  06:51 EDT
        From: Rob MacLachlan <RAM@C.CS.CMU.EDU>

    	Although (THE SHORT-FLOAT 1F0) is quite legal in an
    	implementation in which SHORT-FLOAT and SINGLE-FLOAT are
        identical, it would be reasonable for the compiler to give a warning
        anyway.  Applications that care about this sort of thing will have to
        use a variant version of subtypep that is distinct from the real

    They'll have to do more than that.  If the user wrote
    (THE SHORT-FLOAT 1s0) it would read as exactly the same Lisp object as
    (THE SHORT-FLOAT 1f0) in an implementation where SHORT-FLOAT and
    SINGLE-FLOAT are identical, so I don't see how the compiler could
    distinguish these and give a warning for one but not for the

I realized this was a bad example after I sent the message.  Instead
1F0, substitute <any expression known to be SINGLE-FLOAT>.  For