diff --git a/core/src/replay_stage.rs b/core/src/replay_stage.rs
index d73a55447..a2c9bca86 100644
--- a/core/src/replay_stage.rs
+++ b/core/src/replay_stage.rs
@@ -2118,7 +2118,7 @@ impl ReplayStage {
                 .map_or(false, |sender| sender.should_send_parents)
                 .then(|| {
                     let mut new_chain = rooted_slots.clone();
-                    new_chain.push(oldest_parent.unwrap_or(bank.parent_slot()));
+                    new_chain.push(oldest_parent.unwrap_or_else(|| bank.parent_slot()));
                     new_chain
                 });
 
diff --git a/rpc/src/optimistically_confirmed_bank_tracker.rs b/rpc/src/optimistically_confirmed_bank_tracker.rs
index dcc3792a2..493b03956 100644
--- a/rpc/src/optimistically_confirmed_bank_tracker.rs
+++ b/rpc/src/optimistically_confirmed_bank_tracker.rs
@@ -396,7 +396,7 @@ mod tests {
         let oldest_parent = parents.last().map(|last| last.parent_slot());
         parents.push(bank.clone());
         let mut rooted_slots: Vec<_> = parents.iter().map(|bank| bank.slot()).collect();
-        rooted_slots.push(oldest_parent.unwrap_or(bank.parent_slot()));
+        rooted_slots.push(oldest_parent.unwrap_or_else(|| bank.parent_slot()));
         rooted_slots
     }