Check in codegen test expectations.

test/codegen/expect/language/loop_exchange_test.js

+dart_library.library('language/loop_exchange_test', null, /* Imports */[
+  'dart_sdk',
+  'expect'
+], function load__loop_exchange_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 loop_exchange_test = Object.create(null);
+  let VoidTodynamic = () => (VoidTodynamic = dart.constFn(dart.definiteFunctionType(dart.dynamic, [])))();
+  loop_exchange_test.main = function() {
+    let x = 1;
+    let y = 2;
+    for (let i = 0; i < 2; i++) {
+      if (i == 1) expect$.Expect.equals(2, x);
+      let tmp = x;
+      x = y;
+      y = tmp;
+    }
+  };
+  dart.fn(loop_exchange_test.main, VoidTodynamic());
+  // Exports:
+  exports.loop_exchange_test = loop_exchange_test;
+});