diff --git a/src/codegen.inc.php b/src/codegen.inc.php
index 22fc6fa..9ae550b 100644
--- a/src/codegen.inc.php
+++ b/src/codegen.inc.php
@@ -353,13 +353,13 @@ function data_normalize($name, \mtgType $type, $buf, $dst, $tokens = array(), $t
       $str .= "\$vclass__ = AutogenBundle::getClassName(\$vclass_id__);\n";
       $str .= "if(!is_a(\$vclass__, '{$type->getName()}', true)) throw new Exception(\"'\$vclass__' is not subclass of '{$type->getName()}'\");\n";
       $str .= "\$tmp_sub_mapped__ = array(\$vclass_id__);\n";
-      $str .= "call_user_func_array([\$vclass__, 'normalize'], array(&\$tmp_sub_arr__, &\$tmp_sub_mapped__));\n";
+      $str .= "call_user_func_array([\$vclass__, 'normalize'], array(&\$tmp_sub_arr__, &\$tmp_sub_mapped__, true, \$check_junk));\n";
       $str .= "{$dst}[] = \$tmp_sub_mapped__;\n";
     }
     else
     {
       $str .= "\$tmp_sub_mapped__ = array();\n";
-      $str .= "{$type}::normalize(\$tmp_sub_arr__, \$tmp_sub_mapped__);\n";
+      $str .= "{$type}::normalize(\$tmp_sub_arr__, \$tmp_sub_mapped__, true, \$check_junk);\n";
       $str .= "{$dst}[] = \$tmp_sub_mapped__;\n";
     }
     $str .= "}";
diff --git a/src/data_utils.inc.php b/src/data_utils.inc.php
index 4c12c66..403b454 100644
--- a/src/data_utils.inc.php
+++ b/src/data_utils.inc.php
@@ -222,3 +222,11 @@ function val_blob($val)
 
   return $val;
 }
+
+function check_junk_fields(array $data, array $FIELDS)
+{
+  unset($data['$id']);
+  $diff = array_diff(array_keys($data), $FIELDS); 
+  if($diff)
+    throw new Exception("Junk fields: " . json_encode(array_values($diff)));
+}
diff --git a/tpl/macro.twig b/tpl/macro.twig
index f8bd38c..903bacb 100644
--- a/tpl/macro.twig
+++ b/tpl/macro.twig
@@ -82,6 +82,7 @@ class {{o.name}} {{o.parent ? 'extends ' ~ o.parent.name}}
       $FIELDS = self::CLASS_FIELDS();
       throw new Exception($e->getMessage() . " < {$FIELDS[$IDX]} < ({{o.name}})");
     }
+
     return $IDX;
   }
 
@@ -100,7 +101,7 @@ class {{o.name}} {{o.parent ? 'extends ' ~ o.parent.name}}
     {{_self.export_fields(o)}}
   }
 
-  static function normalize(array &$data, array &$mapped, bool $root = true) : int
+  static function normalize(array &$data, array &$mapped, bool $root = true, bool $check_junk = false) : int
   {
     $IDX = -1;
 
@@ -108,7 +109,7 @@ class {{o.name}} {{o.parent ? 'extends ' ~ o.parent.name}}
     {
       $IDX = 0;
 {%- if o.parent ~%}
-      $IDX = parent::normalize($data, $mapped, false);
+      $IDX = parent::normalize($data, $mapped, false, false);
 {%- endif ~%}
 
 {%- for f in o.fields ~%}
@@ -122,6 +123,9 @@ class {{o.name}} {{o.parent ? 'extends ' ~ o.parent.name}}
       throw new Exception($e->getMessage() . " < {$FIELDS[$IDX]} < ({{o.name}})");
     }
     
+    if($root && $check_junk)
+      \metagen_php\check_junk_fields($data, self::CLASS_FIELDS());
+
     return $IDX;
   }
 }