Recover from read errors.

dart/pkg/compiler/lib/src/elements/modelx.dart

 // Copyright (c) 2013, 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.modelx;
 
 import 'elements.dart';
 import '../constants/expressions.dart';
 import '../helpers/helpers.dart';  // Included for debug helpers.
 import '../tree/tree.dart';
@@ skipping 738 matching lines @@
     }
   }
 
   Element operator [](String name) => importScope[name];
 }
 
 class LibraryElementX
     extends ElementX with AnalyzableElementX, PatchMixin<LibraryElementX>
     implements LibraryElement {
   final Uri canonicalUri;
+
+  /// True if the constructing script was synthesized.
+  final bool isSynthesized;
+
   CompilationUnitElement entryCompilationUnit;
   Link<CompilationUnitElement> compilationUnits =
       const Link<CompilationUnitElement>();
   LinkBuilder<LibraryTag> tagsBuilder = new LinkBuilder<LibraryTag>();
   List<LibraryTag> tagsCache;
   LibraryName libraryTag;
   bool canUseNative = false;
   Link<Element> localMembers = const Link<Element>();
   final ScopeX localScope = new ScopeX();
   final ImportScope importScope = new ImportScope();
@@ skipping 11 matching lines @@
    */
   Link<Element> slotForExports;
 
   final Map<LibraryDependency, LibraryElement> tagMapping =
       new Map<LibraryDependency, LibraryElement>();
 
   LibraryElementX(Script script,
                   [Uri canonicalUri, LibraryElementX origin])
     : this.canonicalUri =
           ((canonicalUri == null) ? script.readableUri : canonicalUri),
+      this.isSynthesized = script.isSynthesized,
       super(script.name, ElementKind.LIBRARY, null) {
     entryCompilationUnit = new CompilationUnitElementX(script, this);
     if (origin != null) {
       origin.applyPatch(this);
     }
   }
 
   bool get isDartCore => canonicalUri == Compiler.DART_CORE;
 
   Link<MetadataAnnotation> get metadata {
@@ skipping 2163 matching lines @@
   AstElement get definingElement;
 
   bool get hasResolvedAst => definingElement.hasTreeElements;
 
   ResolvedAst get resolvedAst {
     return new ResolvedAst(declaration,
         definingElement.node, definingElement.treeElements);
   }
 
 }