diff --git a/rust/hg-cpython/src/ref_sharing.rs b/rust/hg-cpython/src/ref_sharing.rs
--- a/rust/hg-cpython/src/ref_sharing.rs
+++ b/rust/hg-cpython/src/ref_sharing.rs
@@ -179,7 +179,7 @@
         Self { py, owner, data }
     }
 
-    pub fn borrow(&self) -> Ref<T> {
+    pub fn borrow(&self) -> Ref<'a, T> {
         self.data.borrow()
     }