Check in codegen test expectations.

test/codegen/expect/language/type_propagation3_test.js

Index: test/codegen/expect/language/type_propagation3_test.js
diff --git a/test/codegen/expect/language/type_propagation3_test.js b/test/codegen/expect/language/type_propagation3_test.js
new file mode 100644
index 0000000000000000000000000000000000000000..3a9ac5cf573e2d8fa9fbedeeb66016fde14e947f
--- /dev/null
+++ b/test/codegen/expect/language/type_propagation3_test.js
@@ -0,0 +1,68 @@
+dart_library.library('language/type_propagation3_test', null, /* Imports */[
+  'dart_sdk'
+], function load__type_propagation3_test(exports, dart_sdk) {
+  'use strict';
+  const core = dart_sdk.core;
+  const _interceptors = dart_sdk._interceptors;
+  const dart = dart_sdk.dart;
+  const dartx = dart_sdk.dartx;
+  const type_propagation3_test = Object.create(null);
+  let JSArrayOfint = () => (JSArrayOfint = dart.constFn(_interceptors.JSArray$(core.int)))();
+  let VoidTodynamic = () => (VoidTodynamic = dart.constFn(dart.definiteFunctionType(dart.dynamic, [])))();
+  type_propagation3_test.A = class A extends core.Object {
+    next() {
+      return new type_propagation3_test.B();
+    }
+    doIt() {
+      return null;
+    }
+    get isEmpty() {
+      return false;
+    }
+    foo() {
+      return 42;
+    }
+    bar() {
+      return 54;
+    }
+  };
+  dart.setSignature(type_propagation3_test.A, {
+    methods: () => ({
+      next: dart.definiteFunctionType(dart.dynamic, []),
+      doIt: dart.definiteFunctionType(dart.dynamic, []),
+      foo: dart.definiteFunctionType(dart.dynamic, []),
+      bar: dart.definiteFunctionType(dart.dynamic, [])
+    })
+  });
+  type_propagation3_test.entered = false;
+  type_propagation3_test.B = class B extends type_propagation3_test.A {
+    foo() {
+      return 54;
+    }
+    doIt() {
+      return new type_propagation3_test.A();
+    }
+    get isEmpty() {
+      return true;
+    }
+    bar() {
+      return type_propagation3_test.entered = true;
+    }
+  };
+  type_propagation3_test.main = function() {
+    let a = new type_propagation3_test.A();
+    for (let i of JSArrayOfint().of([42])) {
+      a = type_propagation3_test.A._check(a.next());
+    }
+    let b = a;
+    while (dart.test(b.isEmpty)) {
+      b.foo();
+      b.bar();
+      b = type_propagation3_test.A._check(b.doIt());
+    }
+    if (!dart.test(type_propagation3_test.entered)) dart.throw('Test failed');
+  };
+  dart.fn(type_propagation3_test.main, VoidTodynamic());
+  // Exports:
+  exports.type_propagation3_test = type_propagation3_test;
+});