diff --git a/src/Init/Lean/Meta/Tactic/Util.lean b/src/Init/Lean/Meta/Tactic/Util.lean
index 154eacfb25..404f93afe4 100644
--- a/src/Init/Lean/Meta/Tactic/Util.lean
+++ b/src/Init/Lean/Meta/Tactic/Util.lean
@@ -37,7 +37,7 @@ mctx ← getMCtx;
 opts ← getOptions;
 pure $ ppGoal env mctx opts mvarId
 
-@[inline] protected def orelse{α} (x y : MetaM α) : MetaM α := do
+@[inline] protected def orelse {α} (x y : MetaM α) : MetaM α := do
 s ← get; catch x (fun _ => do restore s.env s.mctx s.postponed; y)
 
 instance Meta.hasOrelse {α} : HasOrelse (MetaM α) := ⟨Meta.orelse⟩