Use FastaMessage instead of String. Part 1.

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 'deprecated_problems.dart'
-    show deprecated_InputError, firstSourceUri, deprecated_printUnexpected;
+    show firstSourceUri, deprecated_printUnexpected;
+
+import 'messages.dart' show LocatedMessage, Message, templateUnspecified;
 
 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;
 
   /// List of all handled compile-time errors seen so far by libraries loaded
   /// by this loader.
   ///
   /// A handled error is an error that has been added to the generated AST
   /// already, for example, as a throw expression.
-  final List<deprecated_InputError> handledErrors = <deprecated_InputError>[];
+  final List<LocatedMessage> handledErrors = <LocatedMessage>[];
 
   /// List of all unhandled compile-time errors seen so far by libraries loaded
   /// by this loader.
   ///
   /// An unhandled error is an error that hasn't been handled, see
   /// [handledErrors].
-  final List<deprecated_InputError> unhandledErrors = <deprecated_InputError>[];
+  final List<LocatedMessage> unhandledErrors = <LocatedMessage>[];
 
   LibraryBuilder coreLibrary;
 
   LibraryBuilder first;
 
   int byteCount = 0;
 
   Uri currentUriForCrashReporting;
 
   Loader(this.target);
@@ skipping 106 matching lines @@
   /// Builds all the method bodies found in the given [library].
   Future<Null> buildBody(covariant LibraryBuilder library);
 
   /// Register [message] as a compile-time error.
   ///
   /// If [silent] is true, no error is printed as it is assumed the error has
   /// been previously reported.
   ///
   /// If [wasHandled] is true, this error is added to [handledErrors],
   /// otherwise it is added to [unhandledErrors].
+  void addCompileTimeError(Message message, int charOffset, Uri fileUri,
+      {bool silent: false, bool wasHandled: false}) {
+    if (!silent) {
+      deprecated_printUnexpected(fileUri, charOffset, message.message);
+    }
+    (wasHandled ? handledErrors : unhandledErrors)
+        .add(message.withLocation(fileUri, charOffset));
+  }
+
   void deprecated_addCompileTimeError(
-      Uri fileUri, int charOffset, Object message,
+      Uri fileUri, int charOffset, String message,
       {bool silent: false, bool wasHandled: false}) {
     if (!silent) {
       deprecated_printUnexpected(fileUri, charOffset, message);
     }
-    (wasHandled ? handledErrors : unhandledErrors)
-        .add(new deprecated_InputError(fileUri, charOffset, message));
+    (wasHandled ? handledErrors : unhandledErrors).add(templateUnspecified
+        .withArguments(message)
+        .withLocation(fileUri, charOffset));
   }
 
   Builder getAbstractClassInstantiationError() {
     return target.getAbstractClassInstantiationError(this);
   }
 
   Builder getCompileTimeError() => target.getCompileTimeError(this);
 
   Builder getDuplicatedFieldInitializerError() {
     return target.getDuplicatedFieldInitializerError(this);
   }
 
   Builder getNativeAnnotation() => target.getNativeAnnotation(this);
 }
 
 String format(double d, int fractionDigits, int width) {
   return d.toStringAsFixed(fractionDigits).padLeft(width);
 }