fix: typo at unfoldBothDefEq

src/Lean/Meta/ExprDefEq.lean

@@ -1138,7 +1138,7 @@ private def unfoldBothDefEq (fn : Name) (t s : Expr) : MetaM LBool := do
       pure LBool.true
     else
       unfold t
-       (unfold s (pure LBool.false) (fun s => isDefEqRight fn t s))
+       (unfold s (pure LBool.undef) (fun s => isDefEqRight fn t s))
        (fun t => unfold s (isDefEqLeft fn t s) (fun s => isDefEqLeftRight fn t s))
   | _, _ => pure LBool.false
 

tests/lean/run/interp.lean

@@ -9,7 +9,7 @@ inductive Ty where
   | bool
   | fn (a r : Ty)
 
-@[reducible] def Ty.interp : Ty → Type
+abbrev Ty.interp : Ty → Type
   | int    => Int
   | bool   => Bool
   | fn a r => a.interp → r.interp