Migrated test block 219 to Dart 2.0.

tests/lib_2/mirrors/delegate_class_test.dart

Index: tests/lib_2/mirrors/delegate_class_test.dart
diff --git a/tests/lib_strong/mirrors/delegate_class_test.dart b/tests/lib_2/mirrors/delegate_class_test.dart
similarity index 94%
rename from tests/lib_strong/mirrors/delegate_class_test.dart
rename to tests/lib_2/mirrors/delegate_class_test.dart
index d90e57cd02412f5bf15d95bdb74d49b0270b6c12..83ee8f079d3e2ed092bf236545818056e0e3ba17 100644
--- a/tests/lib_strong/mirrors/delegate_class_test.dart
+++ b/tests/lib_2/mirrors/delegate_class_test.dart
@@ -15,7 +15,6 @@ class C {
   static get getter => 'g';
   static set setter(x) {
     field = x * 2;
-    return 'unobservable value';

[rmacnak, 2017/08/22 16:59:51]

This must be kept.

If this is not expressible in strong mode, the Dart test must be kept around.

[Bob Nystrom, 2017/08/23 22:22:07]

According to the Dart 2.0 language, the static return type of a setter is void
and it is a compile error for a member to return a value that is not assignable
to its return type. This setter is not valid Dart code.

If you want to preserve this test for validating some unspecified behavior or
implementation detail of the VM, that's totally fine. You just need to copy it
out of lib_2/ into some VM-specific testing directory.

lib_2/, corelib_2/, and language_2/ are only for testing the official Dart 2.0
language. I'm guessing you wouldn't feel comfortable seeing a test like this
under language_2/:

main() {
  Expect.equals(1, 1.0); // Ints are doubles on the web.
}

Likewise, we don't want tests of VM-specific behavior in there either.

[rmacnak, 2017/08/23 23:32:04]

This behavior is not VM-specific and is well-specified by Dart (not to be
confused with Dart 2). As long as we are shipping a Dart SDK, we must maintain
test coverage for it.

   }
 
   static var field;
@@ -28,7 +27,7 @@ class Proxy {
 }
 
 main() {
-  var proxy = new Proxy(reflectClass(C));
+  dynamic proxy = new Proxy(reflectClass(C));
   var result;
 
   Expect.equals('X-Y-Z', proxy.method('X', 'Y', 'Z'));