Record static types in the desugaring of null-aware property gets.

pkg/front_end/lib/src/fasta/type_inference/type_inferrer.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.md file.
 
 import 'package:front_end/src/base/instrumentation.dart';
 import 'package:front_end/src/fasta/errors.dart' show internalError;
 import 'package:front_end/src/fasta/kernel/kernel_shadow_ast.dart';
 import 'package:front_end/src/fasta/names.dart' show callName;
 import 'package:front_end/src/fasta/type_inference/type_inference_engine.dart';
 import 'package:front_end/src/fasta/type_inference/type_inference_listener.dart';
@@ skipping 20 matching lines @@
         Name,
         Procedure,
         ProcedureKind,
         PropertyGet,
         PropertySet,
         Statement,
         SuperMethodInvocation,
         SuperPropertyGet,
         SuperPropertySet,
         TypeParameterType,
+        VariableDeclaration,
         VoidType;
 import 'package:kernel/class_hierarchy.dart';
 import 'package:kernel/core_types.dart';
 import 'package:kernel/type_algebra.dart';
 
 /// Keeps track of information about the innermost function or closure being
 /// inferred.
 class ClosureContext {
   final bool isAsync;
 
@@ skipping 577 matching lines @@
   }
 
   /// Performs the core type inference algorithm for property gets (this handles
   /// both null-aware and non-null-aware property gets).
   DartType inferPropertyGet(
       Expression expression,
       Expression receiver,
       int fileOffset,
       PropertyGet desugaredGet,
       DartType typeContext,
-      bool typeNeeded) {
+      bool typeNeeded,
+      {VariableDeclaration receiverVariable}) {
     typeNeeded =
         listener.propertyGetEnter(expression, typeContext) || typeNeeded;
     // First infer the receiver so we can look up the getter that was invoked.
     var receiverType = inferExpression(receiver, null, true);
+    receiverVariable?.type = receiverType;
     Member interfaceMember =
         findInterfaceMember(receiverType, desugaredGet.name, fileOffset);
     if (isTopLevel &&
         ((interfaceMember is Procedure &&
                 interfaceMember.kind == ProcedureKind.Getter) ||
             interfaceMember is Field)) {
       if (TypeInferenceEngineImpl.fullTopLevelInference) {
         if (interfaceMember is KernelField) {
           var accessorNode = KernelMember.getAccessorNode(interfaceMember);
           if (accessorNode != null) {
@@ skipping 87 matching lines @@
   void _forEachArgument(
       Arguments arguments, void callback(String name, Expression expression)) {
     for (var expression in arguments.positional) {
       callback(null, expression);
     }
     for (var namedExpression in arguments.named) {
       callback(namedExpression.name, namedExpression.value);
     }
   }
 }