diff --git a/src/Std/Time/DateTime/PlainDateTime.lean b/src/Std/Time/DateTime/PlainDateTime.lean
index bbfe331812e1..dd6fc91cc785 100644
--- a/src/Std/Time/DateTime/PlainDateTime.lean
+++ b/src/Std/Time/DateTime/PlainDateTime.lean
@@ -30,7 +30,8 @@ structure PlainDateTime where
   -/
   time : PlainTime
 
-  deriving Repr, Inhabited
+  deriving Inhabited, BEq, Repr
+
 
 namespace PlainDateTime