diff --git a/src/util/dictionary/immutable.rs b/src/util/dictionary/immutable.rs
index 84c9cee..5293ed2 100644
--- a/src/util/dictionary/immutable.rs
+++ b/src/util/dictionary/immutable.rs
@@ -43,7 +43,7 @@ impl<'a> Ref<'a> {
 		}
 	}
 
-	pub fn to_owned(&self) -> Owned {
+	pub fn to_owned<'b>(&self) -> Owned<'b> {
 		self.iter().collect()
 	}
 }