[kernel] Support for top-level generic functions.

pkg/kernel/testcases/closures/captured_class_type_vars.dart

Index: pkg/kernel/testcases/closures/captured_class_type_vars.dart
diff --git a/pkg/kernel/testcases/closures/captured_class_type_vars.dart b/pkg/kernel/testcases/closures/captured_class_type_vars.dart
new file mode 100644
index 0000000000000000000000000000000000000000..5767a93c1c23272d6148d483756d5aee3582709e
--- /dev/null
+++ b/pkg/kernel/testcases/closures/captured_class_type_vars.dart
@@ -0,0 +1,16 @@
+// 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.md file.
+
+class Isgen<B> {
+  getfn() {
+    return (x) => x is B;
+  }
+}
+
+main() {
+  int x = 3;
+  var isgen = new Isgen<String>();
+  var iser = isgen.getfn();
+  assert(!iser(x));
+}