Check in codegen test expectations.

test/codegen/expect/language/async_backwards_compatibility_1_test.js

Index: test/codegen/expect/language/async_backwards_compatibility_1_test.js
diff --git a/test/codegen/expect/language/async_backwards_compatibility_1_test.js b/test/codegen/expect/language/async_backwards_compatibility_1_test.js
new file mode 100644
index 0000000000000000000000000000000000000000..51b5519d86066ed9a915724ce1e2e32ac9edac6a
--- /dev/null
+++ b/test/codegen/expect/language/async_backwards_compatibility_1_test.js
@@ -0,0 +1,31 @@
+dart_library.library('language/async_backwards_compatibility_1_test', null, /* Imports */[
+  'dart_sdk'
+], function load__async_backwards_compatibility_1_test(exports, dart_sdk) {
+  'use strict';
+  const core = dart_sdk.core;
+  const dart = dart_sdk.dart;
+  const dartx = dart_sdk.dartx;
+  const async_backwards_compatibility_1_test = Object.create(null);
+  const async_helper_lib = Object.create(null);
+  let VoidToasync = () => (VoidToasync = dart.constFn(dart.definiteFunctionType(async_helper_lib.async, [])))();
+  let VoidTodynamic = () => (VoidTodynamic = dart.constFn(dart.definiteFunctionType(dart.dynamic, [])))();
+  async_backwards_compatibility_1_test.A = class A extends core.Object {
+    get async() {
+      return null;
+    }
+  };
+  async_backwards_compatibility_1_test.topLevel = function() {
+    return null;
+  };
+  dart.lazyFn(async_backwards_compatibility_1_test.topLevel, () => VoidToasync());
+  async_backwards_compatibility_1_test.main = function() {
+    let a = new async_backwards_compatibility_1_test.A();
+    let b = a.async;
+    let c = async_backwards_compatibility_1_test.topLevel();
+  };
+  dart.fn(async_backwards_compatibility_1_test.main, VoidTodynamic());
+  async_helper_lib.async = class async extends core.Object {};
+  // Exports:
+  exports.async_backwards_compatibility_1_test = async_backwards_compatibility_1_test;
+  exports.async_helper_lib = async_helper_lib;
+});