Various infrastructure changes.

pkg/front_end/lib/src/fasta/loader.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.loader;
 
 import 'dart:async' show Future;
 
 import 'dart:collection' show Queue;
 
 import 'builder/builder.dart' show Builder, LibraryBuilder;
 
 import 'errors.dart' show InputError, firstSourceUri;
 
 import 'target_implementation.dart' show TargetImplementation;
 
 import 'ticker.dart' show Ticker;
 
 abstract class Loader<L> {
   final Map<Uri, LibraryBuilder> builders = <Uri, LibraryBuilder>{};
 
   final Queue<LibraryBuilder> unparsedLibraries = new Queue<LibraryBuilder>();
 
   final List<L> libraries = <L>[];
 
   final TargetImplementation target;
 
+  final List<InputError> errors = <InputError>[];
+
   LibraryBuilder coreLibrary;
 
   LibraryBuilder first;
 
   int byteCount = 0;
 
   Uri currentUriForCrashReporting;
 
   Loader(this.target);
 
@@ skipping 93 matching lines @@
 ${format(ms / libraryCount, 3, 12)} ms/compilation unit.""");
     });
   }
 
   Future<Null> buildOutline(covariant LibraryBuilder library);
 
   /// Builds all the method bodies found in the given [library].
   Future<Null> buildBody(covariant LibraryBuilder library);
 
   List<InputError> collectCompileTimeErrors() {
-    List<InputError> errors = <InputError>[];
+    List<InputError> errors = <InputError>[]..addAll(this.errors);
     for (LibraryBuilder library in builders.values) {
       if (library.loader == this) {
         errors.addAll(library.compileTimeErrors);
       }
     }
     return errors;
   }
 
+  Builder getAbstractClassInstantiationError() {
+    return target.getAbstractClassInstantiationError(this);
+  }
+
   Builder getCompileTimeError() => target.getCompileTimeError(this);
 
+  Builder getDuplicatedFieldInitializerError() {
+    return target.getDuplicatedFieldInitializerError(this);
+  }
+
+  Builder getFallThroughError() => target.getFallThroughError(this);
+
   Builder getNativeAnnotation() => target.getNativeAnnotation(this);
 
-  Builder getAbstractClassInstantiationError() {
-    return target.getAbstractClassInstantiationError(this);
-  }
+  Builder getNoSuchMethodError() => target.getNoSuchMethodError(this);
 }
 
 String format(double d, int fractionDigits, int width) {
   return d.toStringAsFixed(fractionDigits).padLeft(width);
 }