diff --git a/bytecode/src/bytecode.rs b/bytecode/src/bytecode.rs
index 427df199c..7fe640c1c 100644
--- a/bytecode/src/bytecode.rs
+++ b/bytecode/src/bytecode.rs
@@ -36,6 +36,9 @@ pub trait Constant: Sized {
     fn into_data(self) -> ConstantData {
         self.borrow_constant().into_data()
     }
+    fn map_constant<Bag: ConstantBag>(self, bag: &Bag) -> Bag::Constant {
+        bag.make_constant(self.into_data())
+    }
 }
 impl Constant for ConstantData {
     fn borrow_constant(&self) -> BorrowedConstant<Self> {
@@ -591,9 +594,13 @@ impl<C: Constant> CodeObject<C> {
         Display(self)
     }
 
-    fn _map_inner<U: Constant>(self, map: impl Fn(C) -> U) -> CodeObject<U> {
+    pub fn map_bag<Bag: ConstantBag>(self, bag: &Bag) -> CodeObject<Bag::Constant> {
         CodeObject {
-            constants: self.constants.into_iter().map(map).collect(),
+            constants: self
+                .constants
+                .into_iter()
+                .map(|x| x.map_constant(bag))
+                .collect(),
 
             instructions: self.instructions,
             label_map: self.label_map,
@@ -610,10 +617,6 @@ impl<C: Constant> CodeObject<C> {
         }
     }
 
-    pub fn map_bag<Bag: ConstantBag>(self, bag: &Bag) -> CodeObject<Bag::Constant> {
-        self._map_inner(|x| bag.make_constant_borrowed(x.borrow_constant()))
-    }
-
     pub fn map_clone_bag<Bag: ConstantBag>(&self, bag: &Bag) -> CodeObject<Bag::Constant> {
         CodeObject {
             constants: self
@@ -651,10 +654,6 @@ impl CodeObject<ConstantData> {
         let data = bincode::serialize(&self).expect("Code object must be serializable");
         lz4_compression::compress::compress(&data)
     }
-
-    pub fn map_basic<Bag: ConstantBag>(self, bag: &Bag) -> CodeObject<Bag::Constant> {
-        self._map_inner(|x| bag.make_constant(x))
-    }
 }
 
 impl<C: Constant> fmt::Display for CodeObject<C> {
diff --git a/vm/src/builtins/code.rs b/vm/src/builtins/code.rs
index 6e251cda0..708df4040 100644
--- a/vm/src/builtins/code.rs
+++ b/vm/src/builtins/code.rs
@@ -70,6 +70,9 @@ impl Constant for PyConstant {
     fn borrow_constant(&self) -> BorrowedConstant<Self> {
         borrow_obj_constant(&self.0)
     }
+    fn map_constant<Bag: ConstantBag>(self, bag: &Bag) -> Bag::Constant {
+        bag.make_constant_borrowed(self.borrow_constant())
+    }
 }
 
 pub(crate) struct PyObjBag<'a>(pub &'a PyContext);
diff --git a/vm/src/pyobject.rs b/vm/src/pyobject.rs
index 48b77cb26..2bb62bf1e 100644
--- a/vm/src/pyobject.rs
+++ b/vm/src/pyobject.rs
@@ -407,7 +407,7 @@ impl PyContext {
     }
 
     pub fn map_codeobj(&self, code: bytecode::CodeObject) -> code::CodeObject {
-        code.map_basic(&code::PyObjBag(self))
+        code.map_bag(&code::PyObjBag(self))
     }
 
     pub fn add_tp_new_wrapper(&self, ty: &PyTypeRef) {