Infer VariableSet types.

pkg/front_end/lib/src/fasta/builder/ast_factory.dart

 // Copyright (c) 2017, 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/scanner.dart' show Token;
 import 'package:front_end/src/fasta/type_inference/type_promotion.dart';
 import 'package:kernel/ast.dart';
 
 /// An abstract class containing factory methods that create AST objects.
 ///
@@ skipping 168 matching lines @@
       String name, Token token, int functionNestingLevel,
       {DartType type,
       Expression initializer,
       Token equalsToken,
       bool isFinal: false,
       bool isConst: false});
 
   /// Creates a read of a local variable.
   VariableGet variableGet(VariableDeclaration variable,
       TypePromotionFact<V> fact, TypePromotionScope scope, Token token);
+
+  /// Creates a write of a local variable.
+  VariableSet variableSet(VariableDeclaration variable, Expression value);
 }