diff --git a/vm/src/builtins/weakproxy.rs b/vm/src/builtins/weakproxy.rs
index 224b18f45..5ff585a73 100644
--- a/vm/src/builtins/weakproxy.rs
+++ b/vm/src/builtins/weakproxy.rs
@@ -47,14 +47,14 @@ impl SlotConstructor for PyWeakProxy {
 impl PyWeakProxy {
     // TODO: callbacks
     #[pymethod(magic)]
-    fn getattr(&self, attr_name: PyObjectRef, vm: &VirtualMachine) -> PyResult {
-        match self.weak.upgrade() {
-            Some(obj) => vm.get_attribute(obj, attr_name),
-            None => Err(vm.new_exception_msg(
+    fn getattr(&self, attr_name: PyStrRef, vm: &VirtualMachine) -> PyResult {
+        let obj = self.weak.upgrade().ok_or_else(|| {
+            vm.new_exception_msg(
                 vm.ctx.exceptions.reference_error.clone(),
                 "weakly-referenced object no longer exists".to_owned(),
-            )),
-        }
+            )
+        })?;
+        vm.get_attribute(obj, attr_name)
     }
 }
 
diff --git a/vm/src/pyobject.rs b/vm/src/pyobject.rs
index d7a588c5d..c0a1283b3 100644
--- a/vm/src/pyobject.rs
+++ b/vm/src/pyobject.rs
@@ -626,15 +626,6 @@ impl<T: PyObjectPayload> TryIntoRef<T> for PyRef<T> {
     }
 }
 
-impl<T> TryIntoRef<T> for PyObjectRef
-where
-    T: PyValue,
-{
-    fn try_into_ref(self, vm: &VirtualMachine) -> PyResult<PyRef<T>> {
-        TryFromObject::try_from_object(vm, self)
-    }
-}
-
 /// Implemented by any type that can be created from a Python object.
 ///
 /// Any type that implements `TryFromObject` is automatically `FromArgs`, and
diff --git a/vm/src/stdlib/errno.rs b/vm/src/stdlib/errno.rs
index 670018148..2e4b456b1 100644
--- a/vm/src/stdlib/errno.rs
+++ b/vm/src/stdlib/errno.rs
@@ -7,9 +7,11 @@ pub fn make_module(vm: &VirtualMachine) -> PyObjectRef {
         "errorcode" => errorcode.clone(),
     });
     for (name, code) in ERROR_CODES {
-        let name = vm.new_pyobj(*name);
+        let name = vm.ctx.new_str(*name);
         let code = vm.new_pyobj(*code);
-        errorcode.set_item(code.clone(), name.clone(), vm).unwrap();
+        errorcode
+            .set_item(code.clone(), name.clone().into(), vm)
+            .unwrap();
         vm.set_attr(&module, name, code).unwrap();
     }
     module