When += (and similar operations) are converted to = + ,

tests/language/src/AssignOpTest.dart

 // Copyright (c) 2011, the Dart project authors.  Please see the AUTHORS file
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 // Dart test program for testing assign operators.
 
 
 class AssignOpTest {
   AssignOpTest() {}
 
   static testMain() {
@@ skipping 48 matching lines @@
     x >>= 3;
     Expect.equals(0x1F, x);
     x <<= 3;
     Expect.equals(0xF8, x);
     x |= 0xF00;
     Expect.equals(0xFF8, x);
     x &=0xF0;
     Expect.equals(0xF0, x);
     x ^=0x11;
     Expect.equals(0xE1, x);
+
+    var y = 100;
+    y += 1 << 3;
+    Expect.equals(108, y);
+    y *= 2 + 1;
+    Expect.equals(324, y);
+    y -= 3 - 2;
+    Expect.equals(323, y);
+    y += 3 * 4;
+    Expect.equals(335, y);
   }
 
   static var f;
   var instf;
 }
 main() {
   AssignOpTest.testMain();
 }