chore: use withAssignableSyntheticOpaque

src/Lean/Elab/Tactic/ElabTerm.lean

@@ -38,7 +38,7 @@ def elabTermEnsuringType (stx : Syntax) (expectedType? : Option Expr) (mayPostpo
     let eType ← inferType e
     -- We allow synthetic opaque metavars to be assigned in the following step since the `isDefEq` is not really
     -- part of the elaboration, but part of the tactic. See issue #492
-    unless (← withAssignableSyntheticOpaque do isDefEq eType expectedType) do
+    unless (← withAssignableSyntheticOpaque <| isDefEq eType expectedType) do
       Term.throwTypeMismatchError none expectedType eType e
     return e
 

src/Lean/Elab/Tactic/Induction.lean

@@ -127,7 +127,7 @@ partial def mkElimApp (elimInfo : ElimInfo) (targets : Array Expr) (tag : Name)
           throwError "insufficient number of targets for '{elimInfo.name}'"
         let target := ctx.targets[s.targetPos]!
         let expectedType ← getArgExpectedType
-        let target ← withConfig (fun cfg => { cfg with assignSyntheticOpaque := true }) do Term.ensureHasType expectedType target
+        let target ← withAssignableSyntheticOpaque <| Term.ensureHasType expectedType target
         modify fun s => { s with targetPos := s.targetPos + 1 }
         addNewArg target
       else match c.binderInfo with