Issue MACRO-FUNCTION-ENVIRONMENT, Version 1

[Richard Mlynarik <Mly@AI.AI.MIT.EDU>]

    Date: Sat, 7 Jan 89 00:15 EST
    From: David A. Moon <Moon@STONY-BROOK.SCRC.Symbolics.COM>

    [...]

    Since use of the compile-time environment for types should be quite rare,
    this was seen as much less of a burden than modifying existing functions
    to take new optional arguments.

Not so.  Consider compiler optimisations of (MAKE-ARRAY # :ELEMENT-TYPE #)
When I last wrote a CL type system I needed a mess of parallel
COMPILER-SUBTYPEP and COMPILER-UPGRADE-ARRAY-ELEMEN-TYPE (and so forth)
functions.  Using compilation-environment technology would have been far
preferable.

I give MAKE-ARRAY optimisation merely as an example -- I feel `user'
code has the same sorts of needs.