--- /usr/local/lib/ruby/gems/1.8/gems/ParseTree-1.7.1/lib/parse_tree.rb.old	Fri Jun 29 22:19:28 2007
+++ /usr/local/lib/ruby/gems/1.8/gems/ParseTree-1.7.1/lib/parse_tree.rb	Fri Jun 29 22:32:40 2007
@@ -454,21 +454,30 @@
     break;
 
   case NODE_ITER:
   case NODE_FOR:
     add_to_parse_tree(current, node->nd_iter, newlines, locals);
     if (node->nd_var != (NODE *)1
         && node->nd_var != (NODE *)2
         && node->nd_var != NULL) {
       add_to_parse_tree(current, node->nd_var, newlines, locals);
     } else {
-      rb_ary_push(current, Qnil);
+      if (node->nd_var == NULL)
+      {
+        // e.g. proc {} 
+        rb_ary_push(current, Qnil);
+      }
+      else
+      {
+        // e.g. proc {||}
+        rb_ary_push(current, ID2SYM(rb_intern("zero_arguments")));
+      }
     }
     add_to_parse_tree(current, node->nd_body, newlines, locals);
     break;
 
   case NODE_BREAK:
   case NODE_NEXT:
   case NODE_YIELD:
     if (node->nd_stts)
       add_to_parse_tree(current, node->nd_stts, newlines, locals);
     break;