diff --git a/src/codegen.inc.php b/src/codegen.inc.php
index 787eb2d..0fbe879 100644
--- a/src/codegen.inc.php
+++ b/src/codegen.inc.php
@@ -122,10 +122,10 @@ function _add_twig_support(\Twig\Environment $twig)
       return is_primary_field($o, $f);
     }
   ));
-  $twig->addFunction(new \Twig\TwigFunction('get_diff_class_units', 
-    function($meta, $o) 
+  $twig->addFunction(new \Twig\TwigFunction('get_diff_related_units', 
+    function($o) 
     { 
-      return get_diff_class_units($meta, $o);
+      return get_diff_related_units($o);
     }
   ));
 }
@@ -440,7 +440,18 @@ function is_nullable_type(\mtgType $type)
          ($type instanceof \mtgMetaStruct && !$type->hasToken('POD'));
 }
 
-function get_diff_class_units(\mtgMetaInfo $meta, \mtgMetaStruct $struct)
+function get_diff_units(\mtgMetaStruct $struct)
 {
-  return [];
+  $result = array();
+  foreach($struct->getFields() as $field)
+  {
+    if($field->hasToken('nodiff'))
+      continue;
+
+    if($field->getType() instanceof mtgMetaStruct)
+      $result[] = $field->getType();
+    else if($field->getType() instanceof mtgArrType)
+      $result[] = $field->getType()->getValue();
+  }
+  return $result;
 }
diff --git a/tpl/macro.twig b/tpl/macro.twig
index a02256a..06594a4 100644
--- a/tpl/macro.twig
+++ b/tpl/macro.twig
@@ -3,17 +3,17 @@
 
 {%- for u in meta.getunits ~%}
 {%- if u.object is instanceof('\\mtgMetaStruct') -%}
-{{ _self.decl_struct(meta, u.object) }}
+{{ _self.decl_struct(u.object) }}
 {%- elseif u.object is instanceof('\\mtgMetaEnum') -%}
 {{ _self.decl_enum(u.object) }}
 {%- elseif u.object is instanceof('\\mtgMetaRPC') -%}
-{{ _self.decl_rpc(meta, u.object) }}
+{{ _self.decl_rpc(u.object) }}
 {%- endif ~%}
 {%- endfor ~%}
 
 {% endmacro %}
 
-{% macro decl_struct(meta, o, extra = '') %}
+{% macro decl_struct(o, extra = '') %}
 {%- if o.parent and has_token(o, 'POD') -%}
 {{Error("@POD structs can't have a parent: " ~ o.name)}}
 {%- endif -%}
@@ -108,7 +108,7 @@ public {{_self.struct_type(o)}} {{o.name}} {{_self.base_struct_class(o)}}
 {%- endif -%}
 
 {%- if has_token(o, 'diffable') ~%}
-  {{_self.diffable_support(meta, o)}}
+  {{_self.diffable_support(o)}}
 {%- endif -%}
 
   {{extra}}
@@ -293,10 +293,10 @@ public enum {{o.name}}
 }
 {% endmacro %}
 
-{% macro decl_rpc(meta, o) %}
+{% macro decl_rpc(o) %}
 
-{{_self.decl_struct(meta, o.req)}}
-{{_self.decl_struct(meta, o.rsp)}}
+{{_self.decl_struct(o.req)}}
+{{_self.decl_struct(o.rsp)}}
 
 public class {{o.name}} : IRpc
 {
@@ -332,9 +332,9 @@ public class {{o.name}} : IRpc
 
 {% endmacro %}
 
-{%- macro diffable_support(meta, o) -%}
+{%- macro diffable_support(o) -%}
 
-    {% for u in get_diff_class_units(meta, o) %}
+    {% for u in get_diff_related_units(o) %}
     {{_self.diff_methods(u)}}
     {% endfor %}