Check in codegen test expectations.

test/codegen/expect/language/issue9949_test.js

+dart_library.library('language/issue9949_test', null, /* Imports */[
+  'dart_sdk',
+  'expect'
+], function load__issue9949_test(exports, dart_sdk, expect) {
+  'use strict';
+  const core = dart_sdk.core;
+  const dart = dart_sdk.dart;
+  const dartx = dart_sdk.dartx;
+  const expect$ = expect.expect;
+  const issue9949_test = Object.create(null);
+  let VoidTovoid = () => (VoidTovoid = dart.constFn(dart.definiteFunctionType(dart.void, [])))();
+  issue9949_test.Crash = class Crash extends core.Expando$(core.String) {
+    new() {
+      super.new();
+    }
+  };
+  dart.addSimpleTypeTests(issue9949_test.Crash);
+  dart.setSignature(issue9949_test.Crash, {
+    constructors: () => ({new: dart.definiteFunctionType(issue9949_test.Crash, [])})
+  });
+  issue9949_test.main = function() {
+    let expando = new issue9949_test.Crash();
+    expect$.Expect.isTrue(core.Expando.is(expando));
+  };
+  dart.fn(issue9949_test.main, VoidTovoid());
+  // Exports:
+  exports.issue9949_test = issue9949_test;
+});