Repro for Issue 19173 - Mirrors + dart2js + checked mode

tests/lib/mirrors/repo_19173/interfaces.dart

Index: tests/lib/mirrors/repo_19173/interfaces.dart
diff --git a/tests/lib/mirrors/repo_19173/interfaces.dart b/tests/lib/mirrors/repo_19173/interfaces.dart
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+// 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 matcher.interfaces;
+
+// To decouple the reporting of errors, and allow for extensibility of
+// matchers, we make use of some interfaces.
+
+/// The ErrorFormatter type is used for functions that
+/// can be used to build up error reports upon [expect] failures.
+/// There is one built-in implementation ([defaultErrorFormatter])
+/// which is used by the default failure handler. If the failure handler
+/// is replaced it may be desirable to replace the [stringDescription]
+/// error formatter with another.
+typedef String ErrorFormatter(actual, Matcher matcher, String reason,
+    Map matchState, bool verbose);
+
+/// Matchers build up their error messages by appending to
+/// Description objects. This interface is implemented by
+/// StringDescription. This interface is unlikely to need
+/// other implementations, but could be useful to replace in
+/// some cases - e.g. language conversion.
+abstract class Description {
+  int get length;
+
+  /// Change the value of the description.
+  Description replace(String text);
+
+  /// This is used to add arbitrary text to the description.
+  Description add(String text);
+
+  /// This is used to add a meaningful description of a value.
+  Description addDescriptionOf(value);
+
+  /// This is used to add a description of an [Iterable] [list],
+  /// with appropriate [start] and [end] markers and inter-element [separator].
+  Description addAll(String start, String separator, String end, Iterable list);
+}
+
+/// [expect] Matchers must implement/extend the Matcher class.
+/// The base Matcher class has a generic implementation of [describeMismatch]
+/// so this does not need to be provided unless a more clear description is
+/// required. The other two methods ([matches] and [describe])
+/// must always be provided as they are highly matcher-specific.
+abstract class Matcher {
+  const Matcher();
+
+  /// This does the matching of the actual vs expected values.
+  /// [item] is the actual value. [matchState] can be supplied
+  /// and may be used to add details about the mismatch that are too
+  /// costly to determine in [describeMismatch].
+  bool matches(item, Map matchState);
+
+  /// This builds a textual description of the matcher.
+  Description describe(Description description);
+
+  /// This builds a textual description of a specific mismatch. [item]
+  /// is the value that was tested by [matches]; [matchState] is
+  /// the [Map] that was passed to and supplemented by [matches]
+  /// with additional information about the mismact, and [mismatchDescription]
+  /// is the [Description] that is being built to decribe the mismatch.
+  /// A few matchers make use of the [verbose] flag to provide detailed
+  /// information that is not typically included but can be of help in
+  /// diagnosing failures, such as stack traces.
+  Description describeMismatch(item, Description mismatchDescription,
+      Map matchState, bool verbose) => mismatchDescription;
+}
+
+/// Failed matches are reported using a default IFailureHandler.
+/// The default implementation simply throws [TestFailure]s;
+/// this can be replaced by some other implementation of
+/// IFailureHandler by calling configureExpectHandler.
+abstract class FailureHandler {
+  /// This handles failures given a textual decription
+  void fail(String reason);
+
+  /// This handles failures given the actual [value], the [matcher]
+  /// the [reason] (argument from [expect]), some additonal [matchState]
+  /// generated by the [matcher], and a verbose flag which controls in
+  /// some cases how much [matchState] information is used. It will use
+  /// these to create a detailed error message (typically by calling
+  /// an [ErrorFormatter]) and then call [fail] with this message.
+  void failMatch(actual, Matcher matcher, String reason,
+                 Map matchState, bool verbose);
+}