sequences: fix filter! to allow stack arguments to be used by the quot.

core/sequences/sequences-tests.factor

@@ -93,6 +93,7 @@ IN: sequences.tests
 { V{ 4 2 6 } } [ V{ 1 4 2 5 3 6 } clone [ 2 mod 0 = ] filter! ] unit-test
 
 { V{ 3 } } [ V{ 1 2 3 } clone 2 [ swap < ] curry filter! ] unit-test
+{ 4 V{ 1 2 3 } } [ 4 V{ 1 4 2 5 3 6 } [ dupd > ] filter! ] unit-test
 
 { "hello world how are you" }
 [ { "hello" "world" "how" "are" "you" } " " join ] unit-test

core/sequences/sequences.factor

@@ -724,7 +724,7 @@ M: slice equal? over slice? [ sequence= ] [ 2drop f ] if ;
 : (filter!) ( ... quot: ( ... elt -- ... ? ) store scan seq -- ... )
     2dup length < [
         [ move-unsafe ] 3keep
-        [ nth-unsafe pick call [ 1 + ] when ] 2keep
+        [ nth-unsafe -rot [ [ call ] keep ] dip rot [ 1 + ] when ] 2keep
         [ 1 + ] dip
         (filter!)
     ] [ nip set-length drop ] if ; inline recursive