diff --git a/src/mrds/trees/unbalanced.rs b/src/mrds/trees/unbalanced.rs
index 513f988..ac01d98 100644
--- a/src/mrds/trees/unbalanced.rs
+++ b/src/mrds/trees/unbalanced.rs
@@ -93,9 +93,7 @@ impl<'a, T: Monad<'a>, A: 'a + Clone> TraversibleBinaryReference<'a, T, A, Unbal
     for UnbalancedReference<'a, T, A>
 {
     fn resolve(&self) -> Wrap<'a, Rc<dyn TraversibleBinaryNode<'a, T, A, UnbalancedData>>, T> {
-        <T as Functor>::fmap(self.0(), |rc| {
-            rc as Rc<dyn TraversibleBinaryNode<'a, T, A, UnbalancedData>>
-        })
+        <T as Functor>::fmap(self.0(), |rc| rc as _)
     }
 
     fn data(&self) -> UnbalancedData {