diff --git a/modules/yaml/yaml.tcl b/modules/yaml/yaml.tcl
index 2ceebe36d..02fd18edc 100644
--- a/modules/yaml/yaml.tcl
+++ b/modules/yaml/yaml.tcl
@@ -1271,7 +1271,7 @@ proc ::yaml::_makeChildType {type tag} {
     namespace eval $full_path_to_type [string map [list @TYPE@ $type @TAG@ $tag] {
 	variable settings
 	set settings {
-	    superClass string
+	    superclass string
 	    publicMethods {}
 	    isContainer no
 	    tag @TAG@
@@ -1288,7 +1288,7 @@ huddle addType [::yaml::_makeChildType str !!str]
 huddle addType [::yaml::_makeChildType timestamp !!timestamp]
 huddle addType [::yaml::_makeChildType float !!float]
 huddle addType [::yaml::_makeChildType int !!int]
-huddle addType [::yaml::_makeChildType null !!null]
+huddle addType [::yaml::_makeChildType y_null !!null]
 huddle addType [::yaml::_makeChildType true !!true]
 huddle addType [::yaml::_makeChildType false !!false]
 huddle addType [::yaml::_makeChildType binary !!binary]
