Unifying compiler context

pkg/front_end/lib/compilation_message.dart

Index: pkg/front_end/lib/compilation_message.dart
diff --git a/pkg/front_end/lib/compilation_message.dart b/pkg/front_end/lib/compilation_message.dart
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+// 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.
+
+/// Defines the API for the front end to communicate information about
+/// compilation messages to clients.
+library front_end.compilation_message;
+
+import 'package:source_span/source_span.dart' show SourceSpan;
+
+import 'package:front_end/src/fasta/severity.dart' show Severity;
+export 'package:front_end/src/fasta/severity.dart' show Severity;
+
+/// A single message, typically an error, reported during compilation, and
+/// information about where it occurred and suggestions on how to fix it.
+///
+/// Not intended to be implemented or extended by clients.
+abstract class CompilationMessage {
+  /// A text description of the problem.
+  String get message;
+
+  /// A suggestion for how to fix the problem. May be `null`.
+  String get tip;
+
+  /// The source span where the error occurred.
+  SourceSpan get span;
+
+  /// The severity level of the error.
+  Severity get severity;
+
+  /// The corresponding analyzer error code, or null if there is no
+  /// corresponding message in analyzer.
+  String get analyzerCode;
+
+  /// The corresponding dart2js error code, or null if there is no corresponding
+  /// message in dart2js.
+  String get dart2jsCode;
+}