Infer VariableSet types.

pkg/front_end/lib/src/fasta/kernel/frontend_accessors.dart

 // Copyright (c) 2016, the Dart project authors.  Please see the AUTHORS file
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
 import 'package:front_end/src/fasta/builder/ast_factory.dart';
 
 /// A library to help transform compounds and null-aware accessors into
 /// let expressions.
 
 import 'package:front_end/src/fasta/kernel/utils.dart' show offsetForToken;
@@ skipping 155 matching lines @@
     var fact = helper.typePromoter
         .getFactForAccess(variable, helper.functionNestingLevel);
     var scope = helper.typePromoter.currentScope;
     return helper.astFactory.variableGet(variable, fact, scope, token);
   }
 
   Expression _makeWrite(Expression value, bool voidContext) {
     helper.typePromoter.mutateVariable(variable, helper.functionNestingLevel);
     return variable.isFinal || variable.isConst
         ? makeInvalidWrite(value)
-        : new VariableSet(variable, value)
+        : helper.astFactory.variableSet(variable, value)
       ..fileOffset = offsetForToken(token);
   }
 }
 
 class PropertyAccessor extends Accessor {
   VariableDeclaration _receiverVariable;
   Expression receiver;
   Name name;
   Member getter, setter;
 
@@ skipping 365 matching lines @@
 
 VariableDeclaration makeOrReuseVariable(Expression value) {
   // TODO: Devise a way to remember if a variable declaration was reused
   // or is fresh (hence needs a let binding).
   return new VariableDeclaration.forValue(value);
 }
 
 Expression wrapInvalid(Expression e) {
   return new Let(new VariableDeclaration.forValue(e), new InvalidExpression());
 }