[es6] implement default/optional parameters (WIP / comments)

src/ast-numbering.cc

Index: src/ast-numbering.cc
diff --git a/src/ast-numbering.cc b/src/ast-numbering.cc
index 1d5420990fc8d150f1999d9cc8607653afdc7037..c2790d19d724cbdb932b774f481998c3426f0531 100644
--- a/src/ast-numbering.cc
+++ b/src/ast-numbering.cc
@@ -523,6 +523,10 @@ void AstNumberingVisitor::VisitArguments(ZoneList<Expression*>* arguments) {
 void AstNumberingVisitor::VisitFunctionLiteral(FunctionLiteral* node) {
   IncrementNodeCount();
   node->set_base_id(ReserveIdRange(FunctionLiteral::num_ids()));
+  if (node->default_values()->length()) {
+    VisitArguments(node->default_values());
+  }
+
   // We don't recurse into the declarations or body of the function literal:
   // you have to separately Renumber() each FunctionLiteral that you compile.
 }
@@ -548,6 +552,8 @@ bool AstNumberingVisitor::Renumber(FunctionLiteral* node) {
     DisableOptimization(kContextAllocatedArguments);
   }
 
+  VisitExpressions(node->default_values());
+
   VisitDeclarations(scope->declarations());
   if (scope->is_function_scope() && scope->function() != NULL) {
     // Visit the name of the named function expression.