Check in codegen test expectations.

test/codegen/expect/corelib/map_keys2_test.js

+dart_library.library('corelib/map_keys2_test', null, /* Imports */[
+  'dart_sdk',
+  'expect'
+], function load__map_keys2_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 map_keys2_test = Object.create(null);
+  let MapOfString$int = () => (MapOfString$int = dart.constFn(core.Map$(core.String, core.int)))();
+  let MapOfString$bool = () => (MapOfString$bool = dart.constFn(core.Map$(core.String, core.bool)))();
+  let IterableOfString = () => (IterableOfString = dart.constFn(core.Iterable$(core.String)))();
+  let IterableOfbool = () => (IterableOfbool = dart.constFn(core.Iterable$(core.bool)))();
+  let VoidTodynamic = () => (VoidTodynamic = dart.constFn(dart.definiteFunctionType(dart.dynamic, [])))();
+  let const$;
+  let const$0;
+  map_keys2_test.main = function() {
+    let map1 = dart.map({foo: 42, bar: 499});
+    let map2 = dart.map();
+    let map3 = const$ || (const$ = dart.const(dart.map({foo: 42, bar: 499})));
+    let map4 = const$0 || (const$0 = dart.const(dart.map()));
+    let map5 = MapOfString$int().new();
+    map5[dartx.set]("foo", 43);
+    map5[dartx.set]("bar", 500);
+    let map6 = MapOfString$bool().new();
+    expect$.Expect.isTrue(IterableOfString().is(map1[dartx.keys]));
+    expect$.Expect.isTrue(IterableOfbool().is(map1[dartx.keys]));
+    expect$.Expect.isTrue(IterableOfString().is(map2[dartx.keys]));
+    expect$.Expect.isTrue(IterableOfbool().is(map2[dartx.keys]));
+    expect$.Expect.isTrue(IterableOfString().is(map3[dartx.keys]));
+    expect$.Expect.isTrue(IterableOfbool().is(map3[dartx.keys]));
+    expect$.Expect.isTrue(IterableOfString().is(map4[dartx.keys]));
+    expect$.Expect.isTrue(IterableOfbool().is(map4[dartx.keys]));
+    expect$.Expect.isTrue(IterableOfString().is(map5[dartx.keys]));
+    expect$.Expect.isFalse(IterableOfbool().is(map5[dartx.keys]));
+    expect$.Expect.isTrue(IterableOfString().is(map6[dartx.keys]));
+    expect$.Expect.isFalse(IterableOfbool().is(map6[dartx.keys]));
+  };
+  dart.fn(map_keys2_test.main, VoidTodynamic());
+  // Exports:
+  exports.map_keys2_test = map_keys2_test;
+});