record which irtree-and-type generations were produced via auto-hooks; skip those when doing typeofs

src/eval/eval_core.h

@@ -318,6 +318,7 @@ struct E_IRTreeAndType
   E_TypeKey type_key;
   void *user_data;
   E_Mode mode;
+  B32 auto_hook;
   E_MsgList msgs;
   E_IRTreeAndType *prev;
 };