[Sbcl-devel] [strandh: Bug report: macro expansion + note about the result]

[<wil...@ai...>]

Robert Strandh sent this report to sbcl-devel-owner, evidently since
the lists are closed to nonsubscribers.

I expect I'll be fielding stuff like this from time to time now. Those
who've sent >40kbyte messages to the lists in the past can guess that 
I usually won't be any more lightning-quick at it than on this message.

----- Forwarded message from Robert Strandh <st...@la...> -----

To: sbc...@li...
Subject: Bug report: macro expansion + note about the result

Hello,

The following code:

   CL-USER> (defgeneric (setf bla) (new-value bla &key whatever))
   #<STANDARD-GENERIC-FUNCTION (SETF BLA) (0)>
   CL-USER> (defun hmm (x y z)
	       (setf (bla x :whatever y) z))

Gives the following note:

   ; in: LAMBDA NIL
   ;     (SETF (BLA X :WHATEVER Y) Z)
   ; --> LET* MULTIPLE-VALUE-BIND LET FUNCALL SB-C::%FUNCALL 
   ; ==>
   ;   (#<SB-C::GLOBAL-VAR
   ;      :%SOURCE-NAME (SETF BLA)
   ;      :TYPE #<SB-KERNEL:FUN-TYPE (FUNCTION # *)>
   ;      :WHERE-FROM :DECLARED
   ;      :KIND :GLOBAL-FUNCTION {10070DEDD1}>
   ;    #:G0 #:G3 #:G2 #:G1)
   ; 
   ; note: The third argument (in keyword position) is not a constant.
   ; 
   ; compilation unit finished
   ;   printed 1 note

The problem seems to be that the macro expansion of:

   (setf (bla x :whatever y) z)

is something similar to 

   (funcall #'(setf bla) #:G0 #:G3 #:G2 #:G1)

where #:G2 is bound to the keyword :whatever.  

Now, since #:G2 is a variable, the compiler emits a note because it is
not very common to have a variable in a keyword position.

Thanks in advance,
-- 
Robert Strandh

---------------------------------------------------------------------
Greenspun's Tenth Rule of Programming: any sufficiently complicated C
or Fortran program contains an ad hoc informally-specified bug-ridden
slow implementation of half of Common Lisp.
---------------------------------------------------------------------

----- End forwarded message -----

-- 
William Harold Newman <wil...@ai...>
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