Insert checks before deferred calls and accesses.

sdk/lib/_internal/compiler/implementation/elements/elements.dart

 // Copyright (c) 2012, 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 elements;
 
 
 import '../tree/tree.dart';
 import '../util/util.dart';
 import '../resolution/resolution.dart';
@@ skipping 813 matching lines @@
   DartType get type;
   FunctionSignature get functionSignature;
   FunctionElement get redirectionTarget;
   FunctionElement get defaultImplementation;
 
   FunctionElement get patch;
   FunctionElement get origin;
 
   bool get isRedirectingFactory;
 
+  /// Used to retrieve a link to the abstract field element representing this
+  /// element.
+  AbstractFieldElement get abstractField;
+
   /**
    * Compute the type of the target of a constructor for an instantiation site
    * with type [:newType:].
    */
   InterfaceType computeTargetType(InterfaceType newType);
 
   // TODO(kasperl): These are bit fishy. Do we really need them?
   void set patch(FunctionElement value);
   void set origin(FunctionElement value);
   void set defaultImplementation(FunctionElement value);
@@ skipping 202 matching lines @@
   int get resolutionState;
   Token get beginToken;
   Token get endToken;
 
   // TODO(kasperl): Try to get rid of these.
   void set annotatedElement(Element value);
 
   MetadataAnnotation ensureResolved(Compiler compiler);
 }
 
+// TODO(johnniwinther): Remove this element.
 abstract class VoidElement extends Element {}
 
 /// An [Element] that has a type.
 abstract class TypedElement extends Element {
   DartType get type;
 }
 
 /// A [MemberSignature] is a member of an interface.
 ///
 /// A signature is either a method or a getter or setter, possibly implicitly
@@ skipping 60 matching lines @@
   InterfaceType get declarer;
 
   /// Returns `true` if this member is static.
   bool get isStatic;
 
   /// Returns `true` if this member is a getter or setter implicitly declared
   /// by a field.
   bool get isDeclaredByField;
 }