Check in codegen test expectations.

test/codegen/expect/language/async_regression_23058_test.js

Index: test/codegen/expect/language/async_regression_23058_test.js
diff --git a/test/codegen/expect/language/async_regression_23058_test.js b/test/codegen/expect/language/async_regression_23058_test.js
new file mode 100644
index 0000000000000000000000000000000000000000..eb1010475e0bd98d33efe5c2916a3606a79c4ec6
--- /dev/null
+++ b/test/codegen/expect/language/async_regression_23058_test.js
@@ -0,0 +1,52 @@
+dart_library.library('language/async_regression_23058_test', null, /* Imports */[
+  'dart_sdk',
+  'async_helper',
+  'expect'
+], function load__async_regression_23058_test(exports, dart_sdk, async_helper, expect) {
+  'use strict';
+  const core = dart_sdk.core;
+  const dart = dart_sdk.dart;
+  const dartx = dart_sdk.dartx;
+  const async_helper$ = async_helper.async_helper;
+  const expect$ = expect.expect;
+  const async_regression_23058_test = Object.create(null);
+  let dynamicTodynamic = () => (dynamicTodynamic = dart.constFn(dart.definiteFunctionType(dart.dynamic, [dart.dynamic])))();
+  let VoidTodynamic = () => (VoidTodynamic = dart.constFn(dart.definiteFunctionType(dart.dynamic, [])))();
+  async_regression_23058_test.A = class A extends core.Object {
+    new() {
+      this.x = new async_regression_23058_test.B();
+    }
+    foo() {
+      return dart.async((function*() {
+        return dart.equals(this.x.foo, 2) ? 42 : this.x.foo;
+      }).bind(this), dart.dynamic);
+    }
+  };
+  dart.setSignature(async_regression_23058_test.A, {
+    methods: () => ({foo: dart.definiteFunctionType(dart.dynamic, [])})
+  });
+  async_regression_23058_test.B = class B extends core.Object {
+    new() {
+      this.x = 0;
+    }
+    get foo() {
+      if (this.x == -1) {
+        return 0;
+      } else {
+        let x = this.x;
+        this.x = dart.notNull(x) + 1;
+        return x;
+      }
+    }
+  };
+  async_regression_23058_test.main = function() {
+    async_helper$.asyncStart();
+    dart.dsend(new async_regression_23058_test.A().foo(), 'then', dart.fn(result => {
+      expect$.Expect.equals(1, result);
+      async_helper$.asyncEnd();
+    }, dynamicTodynamic()));
+  };
+  dart.fn(async_regression_23058_test.main, VoidTodynamic());
+  // Exports:
+  exports.async_regression_23058_test = async_regression_23058_test;
+});