consif true X Y cons X Y consif false U V V filter I nil nil filter J cons X1 Y1 consif J X1 X1 filter J Y1 X a Y c U a V c I a b J a b X1 a Y1 c cons a c c consif b a c c false b filter a b c c nil c true b FULL benchmarks/applicative/AotoYamada_05__028.atrs