Remove unnecessary casts.

pkg/kernel/lib/transformations/closure/converter.dart

Index: pkg/kernel/lib/transformations/closure/converter.dart
diff --git a/pkg/kernel/lib/transformations/closure/converter.dart b/pkg/kernel/lib/transformations/closure/converter.dart
index 9ebd806e1dd6344c1593c272fb21142a0446fb86..8b9ab5cca57e8c13dcf410b0d14687f9df200cfc 100644
--- a/pkg/kernel/lib/transformations/closure/converter.dart
+++ b/pkg/kernel/lib/transformations/closure/converter.dart
@@ -676,8 +676,8 @@ class ClosureConverter extends Transformer {
     String closureClassName = createNameForClosureClass(procedure.function);
     Class closureClass = null;
     for (TreeNode node in newLibraryMembers) {
-      if (node is Class && (node as Class).name == closureClassName) {
-        closureClass = node as Class;
+      if (node is Class && node.name == closureClassName) {

[ahe, 2017/03/16 09:37:09]

Because of the test "node is Class", the compiler now knows that node has the
type Class. As long as you don't assign to node in the code that's guarded by
this test (or in a closure anywhere), there's no need for a cast.

[Dmitry Stefantsov, 2017/03/16 09:42:10]

Thanks!

+        closureClass = node;
       }
     }
     if (closureClass == null) {