Don't re-export hidden members.

pkg/front_end/test/fasta/reexport_test.dart

+// Copyright (c) 2017, 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.
+
+import "package:async_helper/async_helper.dart" show asyncTest;
+
+import "package:front_end/src/testing/compiler_common.dart" show compileUnit;
+
+import "package:front_end/front_end.dart" show CompilerOptions;
+
+main() {
+  asyncTest(() async {
+    var sources = <String, dynamic>{
+      "a.dart": """
+import 'charcode.dart';
+""",
+      "charcode.dart": """
+export 'ascii.dart';
+export 'html_entity.dart' hide tilde;
+""",
+      "html_entity.dart": """
+export 'ascii.dart' show quot;
+const int tilde=1;
+""",
+      "ascii.dart": """
+const int tilde=2;
+const int quot=3;
+""",
+    };
+    await compileUnit(sources.keys.toList(), sources,
+        options: new CompilerOptions()
+          ..onError = (e) => throw "${e.severity}: ${e.message}");
+  });
+}