diff --git a/primitives/externalities/src/lib.rs b/primitives/externalities/src/lib.rs
index 431e449846c6e..fa0f9e4454dd2 100644
--- a/primitives/externalities/src/lib.rs
+++ b/primitives/externalities/src/lib.rs
@@ -203,13 +203,21 @@ pub trait Externalities: ExtensionStore {
/// Returns the SCALE encoded hash.
fn storage_changes_root(&mut self, parent: &[u8]) -> Result