Add some top level type inference rules for property gets.

pkg/front_end/lib/src/fasta/kernel/kernel_shadow_ast.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.
 
 /// This file declares a "shadow hierarchy" of concrete classes which extend
 /// the kernel class hierarchy, adding methods and fields needed by the
 /// BodyBuilder.
 ///
 /// Instances of these classes may be created using the factory methods in
 /// `ast_factory.dart`.
@@ skipping 1142 matching lines @@
   DartType _inferExpression(
       KernelTypeInferrer inferrer, DartType typeContext, bool typeNeeded) {
     typeNeeded =
         inferrer.listener.propertyGetEnter(this, typeContext) || typeNeeded;
     // First infer the receiver so we can look up the getter that was invoked.
     var receiverType = inferrer.inferExpression(receiver, null, true);
     Member interfaceMember;
     if (receiverType is InterfaceType) {
       interfaceMember = inferrer.classHierarchy
           .getInterfaceMember(receiverType.classNode, name);
+      if (inferrer.isTopLevel &&
+          ((interfaceMember is Procedure &&
+                  interfaceMember.kind == ProcedureKind.Getter) ||
+              interfaceMember is Field)) {
+        // References to fields and getters can't be relied upon for top level
+        // inference.
+        inferrer.recordNotImmediatelyEvident(fileOffset);
+      }
       // Our non-strong golden files currently don't include interface targets,
       // so we can't store the interface target without causing tests to fail.
       // TODO(paulberry): fix this.
       if (inferrer.strongMode) {
         inferrer.instrumentation?.record(Uri.parse(inferrer.uri), fileOffset,
             'target', new InstrumentationValueForMember(interfaceMember));
         interfaceTarget = interfaceMember;
       }
     }
     var inferredType =
@@ skipping 744 matching lines @@
   }
 
   transformChildren(v) {
     return internalError("Internal error: Unsupported operation.");
   }
 
   visitChildren(v) {
     return internalError("Internal error: Unsupported operation.");
   }
 }