src/class-finalize-impl.lisp (clos-tiebreaker): Search from the right end.

The docstring clearly says that we take the candidate whose direct
subclass is rightmost in the SO-FAR list, but the code searches SO-FAR
from the left and takes the first match.  As far as I can make out, this
has always been wrong: the earliest version of `merge-lists' builds the
output list in order, and the earliest version of `clos-tiebreaker'
searched from the left anyway.

Just reverse the list before scanning.

diff --git a/src/class-finalize-impl.lisp b/src/class-finalize-impl.lisp
index 6401318f85dfca5d7f3f3046b75ed349c216a60d..b92b604d87a7d360f91c5dcc18f8f1e039468223 100644 (file)
--- a/src/class-finalize-impl.lisp
+++ b/src/class-finalize-impl.lisp
@@ -123,7 +123,7 @@ (defun clos-tiebreaker (candidates so-far)
    direct subclass then that subclass's direct superclasses list must order
    them relative to each other."
 
    direct subclass then that subclass's direct superclasses list must order
    them relative to each other."
 

-  (dolist (class so-far)
+  (dolist (class (reverse so-far))

     (dolist (candidate candidates)
       (when (member candidate (sod-class-direct-superclasses class))
        (return-from clos-tiebreaker candidate))))
     (dolist (candidate candidates)
       (when (member candidate (sod-class-direct-superclasses class))
        (return-from clos-tiebreaker candidate))))