Pantograph/Goal.lean

@@ -164,7 +164,6 @@ protected def GoalState.assign (state: GoalState) (goal: MVarId) (expr: Expr):
       let messages := (← getThe Core.State).messages.getErrorMessages |>.toList.toArray
       let errors ← (messages.map Message.data).mapM fun md => md.toString
       return .failure errors
-    else
     let prevMCtx := state.savedState.term.meta.meta.mctx
     let nextMCtx ← getMCtx
     -- Generate a list of mvarIds that exist in the parent state; Also test the
@@ -346,10 +345,10 @@ protected def GoalState.tryCalc (state: GoalState) (goalId: Nat) (pred: String):
     | .ok syn => pure syn
     | .error error => return .parseError error
   let calcPrevRhs? := state.calcPrevRhsOf? goalId
-  try
-    goal.withContext do
   let target ← instantiateMVars (← goal.getDecl).type
   let tag := (← goal.getDecl).userName
+  try
+    goal.withContext do
 
     let mut step ← Elab.Term.elabType <| ← do
       if let some prevRhs := calcPrevRhs? then
@@ -377,7 +376,7 @@ protected def GoalState.tryCalc (state: GoalState) (goalId: Nat) (pred: String):
 
     -- The calc tactic either solves the main goal or leaves another relation.
     -- Replace the main goal, and save the new goal if necessary
-    if ¬(← Meta.isDefEq proofType target) then
+    unless ← Meta.isDefEq proofType target do
       let rec throwFailed :=
         throwError "'calc' tactic failed, has type{indentExpr proofType}\nbut it is expected to have type{indentExpr target}"
       let some (_, _, rhs) ← Elab.Term.getCalcRelation? proofType | throwFailed