diff --git a/src/flow/traversible/algorithms/subset.rs b/src/flow/traversible/algorithms/subset.rs
index 1066782..5138872 100644
--- a/src/flow/traversible/algorithms/subset.rs
+++ b/src/flow/traversible/algorithms/subset.rs
@@ -29,7 +29,7 @@ impl<'a, T: 'a + MonadFail<()>, A: 'a, D: 'a + PartialEq> SubsetContext<'a, T, A
                     self.comparator,
                     t_subr,
                     self.n_superset.to_tree(),
-                    Some(k_sub.clone()),
+                    Some(k_sub),
                     self.k_r,
                 ),
             ),
@@ -50,7 +50,7 @@ impl<'a, T: 'a + MonadFail<()>, A: 'a, D: 'a + PartialEq> SubsetContext<'a, T, A
                 self.comparator,
                 t_subr,
                 self.t_superr,
-                Some(k_sub.clone()),
+                Some(k_sub),
                 self.k_r,
             ),
         )
@@ -73,7 +73,7 @@ impl<'a, T: 'a + MonadFail<()>, A: 'a, D: 'a + PartialEq> SubsetContext<'a, T, A
                     self.comparator,
                     t_subr,
                     self.t_superr,
-                    Some(k_sub.clone()),
+                    Some(k_sub),
                     self.k_r,
                 ),
             ),