diff --git a/src/obj.rs b/src/obj.rs
index 4bc669c..de3abe0 100644
--- a/src/obj.rs
+++ b/src/obj.rs
@@ -238,7 +238,9 @@ pub trait Obj: Debug + Display + Any + Trace {
         }
     }
 
-    fn type_inst(&self) -> ObjP;
+    fn type_inst(&self) -> ObjP {
+        self.get_attr("__type__").expect("no __type__")
+    }
 
     fn type_name(&self) -> Rc<String> {
         with_obj_downcast(self.type_inst(), |type_inst: &TypeInst| {
@@ -313,10 +315,6 @@ impl Obj for BaseObjInst {
         &mut self.attrs
     }
 
-    fn type_inst(&self) -> ObjP {
-        self.get_attr("__type__").expect("no __type__")
-    }
-
     fn equals(&self, other: &dyn Obj) -> bool {
         if let Some(other) = other.as_any().downcast_ref::<BaseObjInst>() {
             // compare all attrs
diff --git a/src/obj/macros.rs b/src/obj/macros.rs
index 1da5b90..837dd64 100644
--- a/src/obj/macros.rs
+++ b/src/obj/macros.rs
@@ -23,10 +23,6 @@ macro_rules! impl_base_obj {
             self.$base_name.attrs_mut()
         }
 
-        fn type_inst(&self) -> ObjP {
-            self.$base_name.type_inst()
-        }
-
         fn as_any(&self) -> &dyn std::any::Any {
             self
         }