Add type inference for assignment to local variables.

pkg/front_end/lib/src/fasta/kernel/fasta_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.
 
 library fasta.fasta_accessors;
 
 import 'package:front_end/src/fasta/kernel/kernel_shadow_ast.dart'
-    show KernelArguments, KernelComplexAssignment, KernelThisExpression;
+    show
+        KernelArguments,
+        KernelComplexAssignment,
+        KernelIndexAssign,
+        KernelThisExpression,
+        KernelVariableAssignment;
 
 import 'package:front_end/src/fasta/kernel/utils.dart' show offsetForToken;
 
 import 'package:front_end/src/scanner/token.dart' show Token;
 
 import 'frontend_accessors.dart' show Accessor;
 
 import 'package:front_end/src/fasta/type_inference/type_promotion.dart'
     show TypePromoter;
 
@@ skipping 220 matching lines @@
 
   @override
   Expression buildAssignment(Expression value, {bool voidContext: false}) {
     return buildError(new KernelArguments(<Expression>[value]), isSetter: true);
   }
 
   @override
   Expression buildCompoundAssignment(Name binaryOperator, Expression value,
       {int offset: TreeNode.noOffset,
       bool voidContext: false,
-      Procedure interfaceTarget}) {
+      Procedure interfaceTarget,
+      bool isPreIncDec: false}) {
     return buildError(new KernelArguments(<Expression>[value]), isGetter: true);
   }
 
   @override
   Expression buildPrefixIncrement(Name binaryOperator,
       {int offset: TreeNode.noOffset,
       bool voidContext: false,
       Procedure interfaceTarget}) {
     return buildError(new KernelArguments(<Expression>[new IntLiteral(1)]),
         isGetter: true);
@@ skipping 122 matching lines @@
   }
 
   Expression buildNullAwareAssignment(Expression value, DartType type,
       {bool voidContext: false}) {
     return buildAssignmentError();
   }
 
   Expression buildCompoundAssignment(Name binaryOperator, Expression value,
       {int offset: TreeNode.noOffset,
       bool voidContext: false,
-      Procedure interfaceTarget}) {
+      Procedure interfaceTarget,
+      bool isPreIncDec: false}) {
     return buildAssignmentError();
   }
 
   Expression buildPrefixIncrement(Name binaryOperator,
       {int offset: TreeNode.noOffset,
       bool voidContext: false,
       Procedure interfaceTarget}) {
     return buildAssignmentError();
   }
 
@@ skipping 81 matching lines @@
         helper.toValue(receiver), name, arguments, offsetForToken(token),
         isNullAware: isNullAware);
   }
 
   Expression buildNullAwareAssignment(Expression value, DartType type,
       {bool voidContext: false}) {
     return internalError("Unhandled");
   }
 
   Expression buildCompoundAssignment(Name binaryOperator, Expression value,
-      {int offset, bool voidContext: false, Procedure interfaceTarget}) {
+      {int offset,
+      bool voidContext: false,
+      Procedure interfaceTarget,
+      bool isPreIncDec: false}) {
     return internalError("Unhandled");
   }
 
   Expression buildPrefixIncrement(Name binaryOperator,
       {int offset, bool voidContext: false, Procedure interfaceTarget}) {
     return internalError("Unhandled");
   }
 
   Expression buildPostfixIncrement(Name binaryOperator,
       {int offset, bool voidContext: false, Procedure interfaceTarget}) {
@@ skipping 35 matching lines @@
     return PropertyAccessor.make(
         helper, token, helper.toValue(receiver), name, null, null, isNullAware);
   }
 
   Expression buildNullAwareAssignment(Expression value, DartType type,
       {bool voidContext: false}) {
     return internalError("Unhandled");
   }
 
   Expression buildCompoundAssignment(Name binaryOperator, Expression value,
-      {int offset, bool voidContext: false, Procedure interfaceTarget}) {
+      {int offset,
+      bool voidContext: false,
+      Procedure interfaceTarget,
+      bool isPreIncDec: false}) {
     return internalError("Unhandled");
   }
 
   Expression buildPrefixIncrement(Name binaryOperator,
       {int offset, bool voidContext: false, Procedure interfaceTarget}) {
     return internalError("Unhandled");
   }
 
   Expression buildPostfixIncrement(Name binaryOperator,
       {int offset, bool voidContext: false, Procedure interfaceTarget}) {
@@ skipping 39 matching lines @@
     if (receiver is ThisExpression) {
       return new ThisIndexAccessor(helper, token, index, getter, setter);
     } else {
       return new IndexAccessor.internal(
           helper, token, receiver, index, getter, setter);
     }
   }
 
   @override
   KernelComplexAssignment startComplexAssignment(Expression rhs) =>
-      new KernelComplexAssignment()
-        ..receiver = receiver
-        ..index = index
-        ..rhs = rhs;
+      new KernelIndexAssign(receiver, index, rhs);
 }
 
 class PropertyAccessor extends kernel.PropertyAccessor with FastaAccessor {
   final BuilderHelper helper;
 
   PropertyAccessor.internal(this.helper, Token token, Expression receiver,
       Name name, Member getter, Member setter)
       : super.internal(helper, receiver, name, getter, setter, token);
 
   String get plainNameForRead => name.name;
@@ skipping 212 matching lines @@
 
   String get plainNameForRead => variable.name;
 
   Expression doInvocation(int offset, Arguments arguments) {
     return helper.buildMethodInvocation(buildSimpleRead(), callName, arguments,
         adjustForImplicitCall(plainNameForRead, offset),
         isImplicitCall: true);
   }
 
   toString() => "VariableAccessor()";
+
+  @override
+  KernelComplexAssignment startComplexAssignment(Expression rhs) =>
+      new KernelVariableAssignment(rhs);
 }
 
 class ReadOnlyAccessor extends kernel.ReadOnlyAccessor with FastaAccessor {
   final String plainNameForRead;
 
   ReadOnlyAccessor(BuilderHelper helper, Expression expression,
       this.plainNameForRead, Token token)
       : super(helper, expression, token);
 
   Expression doInvocation(int offset, Arguments arguments) {
@@ skipping 125 matching lines @@
     offset ??= offsetForToken(this.token);
     return helper.throwNoSuchMethodError(new NullLiteral()..fileOffset = offset,
         plainNameForRead, arguments, offset,
         isGetter: isGetter, isSetter: isSetter);
   }
 }
 
 bool isFieldOrGetter(Member member) {
   return member is Field || (member is Procedure && member.isGetter);
 }