Fix crash with bad each-object usage

core/memory/memory-tests.factor

@@ -23,3 +23,6 @@ TUPLE: testing x y z ;
         ] when*
     ] each
 ] unit-test
+
+! Erg's bug
+2 [ [ [ 3 throw ] instances ] must-fail ] times

core/memory/memory.factor

@@ -1,17 +1,15 @@
-! Copyright (C) 2005, 2007 Slava Pestov.
+! Copyright (C) 2005, 2008 Slava Pestov.
 ! See http://factorcode.org/license.txt for BSD license.
+USING: kernel continuations sequences arrays system ;
 IN: memory
-USING: arrays kernel sequences vectors system hashtables
-kernel.private sbufs growable assocs namespaces quotations
-math strings combinators ;
 
 : (each-object) ( quot: ( obj -- ) -- )
     [ next-object dup ] swap [ drop ] while ; inline
 
 : each-object ( quot -- )
-    begin-scan (each-object) end-scan ; inline
+    begin-scan [ (each-object) ] [ end-scan ] [ ] cleanup ; inline
 
 : instances ( quot -- seq )
-    pusher >r each-object r> >array ; inline
+    pusher [ each-object ] dip >array ; inline
 
 : save ( -- ) image save-image ;