Handle implicitly hidden exports.

tests/language/regress_20935_test.dart

Index: tests/language/regress_20935_test.dart
diff --git a/pkg/docgen/test/multi_library_code/lib/test_lib2_foo.dart b/tests/language/regress_20935_test.dart
similarity index 68%
copy from pkg/docgen/test/multi_library_code/lib/test_lib2_foo.dart
copy to tests/language/regress_20935_test.dart
index 1b3d037c5bce3add4829e93b527bc5eb7f01f821..a7cfa4ba54072da22971c00e843e40f6678c6a10 100644
--- a/pkg/docgen/test/multi_library_code/lib/test_lib2_foo.dart
+++ b/tests/language/regress_20935_test.dart
@@ -2,14 +2,12 @@
 // 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 test_lib2_foo;
+// Regression test for issue 20935.
 
-export 'test_lib2_bar.dart';
+import 'regress_20935_foo.dart';
 
-class Foo {
-
-}
+baz(x) => x*2;
 
 main() {
-  print('hello world');
+  print(baz is Future);
 }