(setf compiler-macro-function)

[Kris Katterjohn]

Hello,

It seems that defining compiler macros with define-compiler-macro works
but setting with setf doesn't.

In particular, I'm wanting to use setf with a value of nil to remove a
possibly existing compiler macro definition.  However, when I do this in
GCL I get an error:

GCL (GNU Common Lisp)  2.6.12 ANSI    Fri Apr 22 15:51:11 UTC 2016
<snip>

>(setf (compiler-macro-function 'foo) nil)

Error: 
Fast links are on: do (si::use-fast-links nil) for debugging
Signalled by EVAL.
Condition in EVAL [or a callee]: INTERNAL-SIMPLE-PROGRAM-ERROR: Cannot expand 
the SETF form (COMPILER-MACRO-FUNCTION (QUOTE FOO)).

Broken at SETF.  Type :H for Help.
    1  Return to top level.


Is this a known problem?

This is for a bugfix in Maxima.  Do you have any advice on what to do
here when using GCL?

I see that system:undef-compiler-macro exists.  Does this do what I'm
wanting (as the name suggests)?  If so, will it continue to be around in
the future even if the stuff above is working?

Cheers,
Kris Katterjohn