diff --git a/sealable-trie/src/nodes.rs b/sealable-trie/src/nodes.rs
index 29a09069..2814e714 100644
--- a/sealable-trie/src/nodes.rs
+++ b/sealable-trie/src/nodes.rs
@@ -208,12 +208,16 @@ impl<'a, P, S> Node<'a, P, S> {
                 // tag = 0b100v_0000 where v indicates whether the child is
                 // a value reference.
                 let tag = 0x80 | (u8::from(child.is_value()) << 4);
-                // XXX
-                if let Ok(len) = key.encode_into(key_buf, tag) {
-                    buf[len..len + 32].copy_from_slice(child.hash().as_slice());
-                    len + 32
-                } else {
-                    return hash_extension_slow_path(*key, child);
+                match key.encode_into(key_buf, tag) {
+                    Ok(len) => {
+                        buf[len..len + 32]
+                            .copy_from_slice(child.hash().as_slice());
+                        len + 32
+                    }
+                    Err(bits::EncodeError::EmptySlice) => {
+                        return hash_extension_slow_path(*key, child);
+                    }
+                    Err(bits::EncodeError::SliceTooLong) => unreachable!(),
                 }
             }
         };