Fix --dump=parsetree segfault on required keyword argument

* node.c (dump_node): handle nd_value == (NODE *)-1 to mean this
  keyword argument is required

git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@46649 b2dd03c8-39d4-4d8f-98ff-823fe69b080e

ChangeLog

@@ -1,3 +1,8 @@
+Wed Jul  2 03:20:00 2014  Charlie Somerville  <charliesome@ruby-lang.org>
+
+	* node.c (dump_node): handle nd_value == (NODE *)-1 to mean this
+	  keyword argument is required
+
 Wed Jul  2 02:57:27 2014  Nobuyoshi Nakada  <nobu@ruby-lang.org>
 
 	* vm.c (rb_vm_env_local_variables): returns array of local

node.c

@@ -300,7 +300,12 @@ dump_node(VALUE buf, VALUE indent, int comment, NODE *node)
       asgn:
 	F_ID(nd_vid, "variable");
 	LAST_NODE;
-	F_NODE(nd_value, "rvalue");
+	if (node->nd_value == (NODE *)-1) {
+	    F_MSG(nd_value, "rvalue", "(required keyword argument)");
+	}
+	else {
+	    F_NODE(nd_value, "rvalue");
+	}
 	break;
 
       case NODE_GASGN: