Order the parameters of a function at the definition site.

lib/compiler/implementation/js_backend/namer.dart

Index: lib/compiler/implementation/js_backend/namer.dart
===================================================================
--- lib/compiler/implementation/js_backend/namer.dart	(revision 12897)
+++ lib/compiler/implementation/js_backend/namer.dart	(working copy)
@@ -111,11 +111,13 @@
     if (!signature.optionalParametersAreNamed) {
       return methodName;
     } else {
-      StringBuffer suffix = new StringBuffer();
-      signature.forEachOptionalParameter((Element element) {
-        String jsName = JsNames.getValid(element.name.slowToString());        
-        suffix.add('\$$jsName');
+      List<String> optionalParameters = <String>[];

[kasperl, 2012/09/26 11:53:55]

Maybe check if optionalParameters.isEmpty first and just return methodName. That
should be a bit faster and it simplifies the logic a bit.

[ngeoffray, 2012/09/26 12:28:47]

Done.

+      signature.orderedOptionalParameters.forEach((Element element) {
+        optionalParameters.add(JsNames.getValid(element.name.slowToString()));
       });
+      String suffix = optionalParameters.isEmpty()
+          ? ''
+          : "\$${Strings.join(optionalParameters, '\$')}";
       return '$methodName$suffix';
     }
   }