Import rasta tests.

pkg/fasta/test/rasta/typedef.dart

Index: pkg/fasta/test/rasta/typedef.dart
diff --git a/pkg/fasta/test/rasta/typedef.dart b/pkg/fasta/test/rasta/typedef.dart
new file mode 100644
index 0000000000000000000000000000000000000000..37e26a6359a3ce64816e28bf3a638150d6089c55
--- /dev/null
+++ b/pkg/fasta/test/rasta/typedef.dart
@@ -0,0 +1,12 @@
+// 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.md file.
+
+typedef void Foo();
+
+main() {
+  print(Foo);
+  Foo = null;
+  Foo ??= null;
+  Foo();
+}