Return newValue from indexSet helper and other intercepted setters. Also, throw IllegalArgumentExce…

dart/frog/leg/lib/js_helper.dart

 // Copyright (c) 2012, 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.
 
 #library('js_helper');
 
 #import('coreimpl.dart');
 
 #source('date_helper.dart');
 #source('regexp_helper.dart');
@@ skipping 227 matching lines @@
   if (isJsArray(a)) {
     if (!(index is int)) {
       throw new IllegalArgumentException(index);
     }
     if (index < 0 || index >= a.length) {
       throw new IndexOutOfRangeException(index);
     }
     return JS("Object", @"$0[$1] = $2", a, index, value);
   }
   checkNull(a);
-  return UNINTERCEPTED(a[index] = value);
+  UNINTERCEPTED(a[index] = value);
+  return value;
 }
 
 builtin$add$1(var receiver, var value) {
   checkNull(receiver);
   if (isJsArray(receiver)) {
     JS("Object", @"$0.push($1)", receiver, value);
     return;
   }
   return UNINTERCEPTED(receiver.add(value));
 }
@@ skipping 28 matching lines @@
 builtin$set$length(receiver, newLength) {
   checkNull(receiver);
   if (isJsArray(receiver)) {
     checkNull(newLength); // TODO(ahe): This is not specified but co19 tests it.
     if (newLength is !int) throw new IllegalArgumentException(newLength);
     if (newLength < 0) throw new IndexOutOfRangeException(newLength);
     JS('void', @"$0.length = $1", receiver, newLength);
   } else {
     UNINTERCEPTED(receiver.length = newLength);
   }
+  return newLength;
 }
 
 builtin$toString$0(var value) {
   if (JS("bool", @"typeof $0 == 'object'", value)) {
     if (isJsArray(value)) {
       return "Instance of 'List'";
     }
     return UNINTERCEPTED(value.toString());
   }
   if (JS("bool", @"$0 === 0 && (1 / $0) < 0", value)) {
@@ skipping 277 matching lines @@
   checkNull(receiver);
   if (!isJsArray(receiver)) {
     return UNINTERCEPTED(receiver.getRange(start, length));
   }
   if (0 === length) return [];
   checkNull(start); // TODO(ahe): This is not specified but co19 tests it.
   checkNull(length); // TODO(ahe): This is not specified but co19 tests it.
   if (start is !int) throw new IllegalArgumentException(start);
   if (length is !int) throw new IllegalArgumentException(length);
   if (start < 0) throw new IndexOutOfRangeException(start);
+  if (length < 0) throw new IllegalArgumentException(length);
   var end = start + length;
   if (end > receiver.length) {
     throw new IndexOutOfRangeException(length);
   }
   if (length < 0) throw new IllegalArgumentException(length);
   return JS("Object", @"$0.slice($1, $2)", receiver, start, end);
 }
 
 builtin$indexOf$1(receiver, element) {
   checkNull(receiver);
@@ skipping 547 matching lines @@
     throw 'String.hashCode is not implemented';
   }
   if (isJsArray(receiver)) {
     throw 'List.hashCode is not implemented';
   }
   return UNINTERCEPTED(receiver.hashCode());
 }
 
 // TODO(ahe): Dynamic may be overridden.
 builtin$get$dynamic(receiver) => receiver;