kcl bug

[vax135!lcuxle!elia@ucbvax.berkeley.edu (Weixelbaum Elia)]

Consider the following function:

(DEFUN FOO (&OPTIONAL (A NIL B) &REST C) (LIST A B C))

When (FOO 'X 'Y 'Z) is called uncompiled, it correctly returns (X T (Y Z)).
However, when called compiled, (FOO 'X 'Y 'Z) returns (X (T) (Y T)).

Apparently, the run-time stack begins as:
-------------
| X | Y | Z |
-------------

It seems that the compiler uses the same space on their run-time stack
for Z and the value supplied for the supplied-p parameter -- B.  That
same location is used in part of the conversion of the &REST arguments
into a list.  Therefore, after handling B, the stack becomes:
-------------
| X | Y | T |
-------------

Then, in order to handle conversion of the &REST arguments, the stack
becomes:
-------------------------
| X | (Y T) | (T) | NIL |
-------------------------

Elia Weixelbaum