diff --git a/src/codegen.inc.php b/src/codegen.inc.php
index 5124911..d5231e6 100644
--- a/src/codegen.inc.php
+++ b/src/codegen.inc.php
@@ -468,7 +468,7 @@ function is_nullable_type(\mtgType $type)
          ($type instanceof \mtgMetaStruct && !$type->hasToken('POD'));
 }
 
-function get_diff_units(\mtgMetaStruct $struct)
+function get_diff_related_units(\mtgMetaStruct $struct)
 {
   $result = array();
   foreach($struct->getFields() as $field)