diff --git a/Lib/test/test_weakref.py b/Lib/test/test_weakref.py
index 99a19fe4b8..a661a59610 100644
--- a/Lib/test/test_weakref.py
+++ b/Lib/test/test_weakref.py
@@ -1856,6 +1856,7 @@ def test_threaded_weak_value_dict_copy(self):
         # copying should not result in a crash.
         self.check_threaded_weak_dict_copy(weakref.WeakValueDictionary, False)
 
+    @unittest.skip("TODO: RUSTPYTHON; flaky test")
     def test_threaded_weak_value_dict_deepcopy(self):
         # Issue #35615: Weakref keys or values getting GC'ed during dict
         # copying should not result in a crash.
diff --git a/vm/src/builtins/object.rs b/vm/src/builtins/object.rs
index 4d1173e1b4..305f64b22e 100644
--- a/vm/src/builtins/object.rs
+++ b/vm/src/builtins/object.rs
@@ -77,10 +77,7 @@ impl PyBaseObject {
                 }
             }
             PyComparisonOp::Ne => {
-                let cmp = zelf
-                    .class()
-                    .mro_find_map(|cls| cls.slots.richcompare.load())
-                    .unwrap();
+                let cmp = zelf.class().slots.richcompare.load().unwrap();
                 let value = match cmp(zelf, other, PyComparisonOp::Eq, vm)? {
                     Either::A(obj) => PyArithmeticValue::from_object(vm, obj)
                         .map(|obj| obj.try_to_bool(vm))
diff --git a/vm/src/builtins/type.rs b/vm/src/builtins/type.rs
index 3395a05e3e..52ce3c6e30 100644
--- a/vm/src/builtins/type.rs
+++ b/vm/src/builtins/type.rs
@@ -95,6 +95,8 @@ impl PyType {
             .map(|x| x.iter_mro().cloned().collect())
             .collect();
         let mro = linearise_mro(mros)?;
+        slots.inherits(&mro.iter().map(|t| -> &PyType { &t }).collect::<Vec<_>>());
+        debug_assert!(slots.hash.load().is_some(), "{}", name);
 
         if base.slots.flags.has_feature(PyTypeFlags::HAS_DICT) {
             slots.flags |= PyTypeFlags::HAS_DICT
@@ -141,19 +143,6 @@ impl PyType {
         std::iter::once(self).chain(self.mro.iter().map(|cls| -> &PyType { cls }))
     }
 
-    pub(crate) fn mro_find_map<F, R>(&self, f: F) -> Option<R>
-    where
-        F: Fn(&Self) -> Option<R>,
-    {
-        // the hot path will be primitive types which usually hit the result from itself.
-        // try std::intrinsics::likely once it is stablized
-        if let Some(r) = f(self) {
-            Some(r)
-        } else {
-            self.mro.iter().find_map(|cls| f(cls))
-        }
-    }
-
     // This is used for class initialisation where the vm is not yet available.
     pub fn set_str_attr<V: Into<PyObjectRef>>(&self, attr_name: &str, value: V) {
         self._set_str_attr(attr_name, value.into())
@@ -521,7 +510,7 @@ impl PyType {
         // updated when __slots__ are supported (toggling the flag off if
         // a class has __slots__ defined).
         let flags = PyTypeFlags::heap_type_flags() | PyTypeFlags::HAS_DICT;
-        let slots = PyTypeSlots::from_flags(flags);
+        let slots = PyTypeSlots::with_flags(flags);
 
         let typ = Self::new_verbose_ref(name.as_str(), base, bases, attributes, slots, metatype)
             .map_err(|e| vm.new_type_error(e))?;
@@ -637,11 +626,8 @@ impl GetAttr for PyType {
 
         if let Some(ref attr) = mcl_attr {
             let attr_class = attr.class();
-            if attr_class
-                .mro_find_map(|cls| cls.slots.descr_set.load())
-                .is_some()
-            {
-                if let Some(descr_get) = attr_class.mro_find_map(|cls| cls.slots.descr_get.load()) {
+            if attr_class.slots.descr_set.load().is_some() {
+                if let Some(descr_get) = attr_class.slots.descr_get.load() {
                     let mcl = mcl.into_owned().into();
                     return descr_get(attr.clone(), Some(zelf.to_owned().into()), Some(mcl), vm);
                 }
@@ -651,7 +637,7 @@ impl GetAttr for PyType {
         let zelf_attr = zelf.get_attr(name);
 
         if let Some(ref attr) = zelf_attr {
-            if let Some(descr_get) = attr.class().mro_find_map(|cls| cls.slots.descr_get.load()) {
+            if let Some(descr_get) = attr.class().slots.descr_get.load() {
                 drop(mcl);
                 return descr_get(attr.clone(), None, Some(zelf.to_owned().into()), vm);
             }
@@ -680,7 +666,7 @@ impl SetAttr for PyType {
         vm: &VirtualMachine,
     ) -> PyResult<()> {
         if let Some(attr) = zelf.get_class_attr(attr_name.as_str()) {
-            let descr_set = attr.class().mro_find_map(|cls| cls.slots.descr_set.load());
+            let descr_set = attr.class().slots.descr_set.load();
             if let Some(descriptor) = descr_set {
                 return descriptor(attr, zelf.to_owned().into(), value, vm);
             }
@@ -719,7 +705,7 @@ impl Callable for PyType {
             return Ok(obj);
         }
 
-        if let Some(init_method) = obj.class().mro_find_map(|cls| cls.slots.init.load()) {
+        if let Some(init_method) = obj.class().slots.init.load() {
             init_method(obj.clone(), args, vm)?;
         }
         Ok(obj)
@@ -757,15 +743,12 @@ fn subtype_set_dict(obj: PyObjectRef, value: PyObjectRef, vm: &VirtualMachine) -
     let cls = obj.class().clone();
     match find_base_dict_descr(&cls, vm) {
         Some(descr) => {
-            let descr_set = descr
-                .class()
-                .mro_find_map(|cls| cls.slots.descr_set.load())
-                .ok_or_else(|| {
-                    vm.new_type_error(format!(
-                        "this __dict__ descriptor does not support '{}' objects",
-                        cls.name()
-                    ))
-                })?;
+            let descr_set = descr.class().slots.descr_set.load().ok_or_else(|| {
+                vm.new_type_error(format!(
+                    "this __dict__ descriptor does not support '{}' objects",
+                    cls.name()
+                ))
+            })?;
             descr_set(descr, obj, Some(value), vm)
         }
         None => {
diff --git a/vm/src/function/protocol.rs b/vm/src/function/protocol.rs
index 9d5b54a5a1..6889d22542 100644
--- a/vm/src/function/protocol.rs
+++ b/vm/src/function/protocol.rs
@@ -85,7 +85,7 @@ where
         let iterfn;
         {
             let cls = obj.class();
-            iterfn = cls.mro_find_map(|x| x.slots.iter.load());
+            iterfn = cls.slots.iter.load();
             if iterfn.is_none() && !cls.has_attr("__getitem__") {
                 return Err(vm.new_type_error(format!("'{}' object is not iterable", cls.name())));
             }
diff --git a/vm/src/macros.rs b/vm/src/macros.rs
index eff8917495..a886dd51be 100644
--- a/vm/src/macros.rs
+++ b/vm/src/macros.rs
@@ -17,7 +17,7 @@ macro_rules! py_class {
     ( $ctx:expr, $class_name:expr, $class_base:expr, $flags:expr, { $($name:tt => $value:expr),* $(,)* }) => {
         {
             #[allow(unused_mut)]
-            let mut slots = $crate::types::PyTypeSlots::from_flags($crate::types::PyTypeFlags::DEFAULT | $flags);
+            let mut slots = $crate::types::PyTypeSlots::with_flags($crate::types::PyTypeFlags::DEFAULT | $flags);
             $($crate::py_class!(@extract_slots($ctx, &mut slots, $name, $value));)*
             let py_class = $ctx.new_class(None, $class_name, $class_base, slots);
             $($crate::py_class!(@extract_attrs($ctx, &py_class, $name, $value));)*
diff --git a/vm/src/object/core.rs b/vm/src/object/core.rs
index 19c7aa47ec..dc17d4dbca 100644
--- a/vm/src/object/core.rs
+++ b/vm/src/object/core.rs
@@ -762,7 +762,7 @@ impl PyObject {
         }
 
         // CPython-compatible drop implementation
-        if let Some(slot_del) = self.class().mro_find_map(|cls| cls.slots.del.load()) {
+        if let Some(slot_del) = self.class().slots.del.load() {
             call_slot_del(self, slot_del)?;
         }
         if let Some(wrl) = self.weak_ref_list() {
@@ -1081,22 +1081,25 @@ pub(crate) fn init_type_hierarchy() -> (PyTypeRef, PyTypeRef, PyTypeRef) {
         static_assertions::assert_eq_size!(MaybeUninit<PyInner<PyType>>, PyInner<PyType>);
         static_assertions::assert_eq_align!(MaybeUninit<PyInner<PyType>>, PyInner<PyType>);
 
-        let type_payload = PyType {
+        let object_payload = PyType {
             base: None,
             bases: vec![],
             mro: vec![],
             subclasses: PyRwLock::default(),
             attributes: PyRwLock::new(Default::default()),
-            slots: PyType::make_slots(),
+            slots: object::PyBaseObject::make_slots(),
         };
-        let object_payload = PyType {
+        let mut type_slots = PyType::make_slots();
+        type_slots.inherits(&[&object_payload]);
+        let type_payload = PyType {
             base: None,
             bases: vec![],
             mro: vec![],
             subclasses: PyRwLock::default(),
             attributes: PyRwLock::new(Default::default()),
-            slots: object::PyBaseObject::make_slots(),
+            slots: type_slots,
         };
+
         let type_type_ptr = Box::into_raw(Box::new(partially_init!(
             PyInner::<PyType> {
                 ref_count: RefCount::new(),
@@ -1149,13 +1152,15 @@ pub(crate) fn init_type_hierarchy() -> (PyTypeRef, PyTypeRef, PyTypeRef) {
         }
     };
 
+    let mut weakref_slots = PyWeak::make_slots();
+    weakref_slots.inherits(&[&object_type]);
     let weakref_type = PyType {
         base: Some(object_type.clone()),
         bases: vec![object_type.clone()],
         mro: vec![object_type.clone()],
         subclasses: PyRwLock::default(),
         attributes: PyRwLock::default(),
-        slots: PyWeak::make_slots(),
+        slots: weakref_slots,
     };
     let weakref_type = PyRef::new_ref(weakref_type, type_type.clone(), None);
 
diff --git a/vm/src/protocol/buffer.rs b/vm/src/protocol/buffer.rs
index 9f4c191be0..26426d2ec7 100644
--- a/vm/src/protocol/buffer.rs
+++ b/vm/src/protocol/buffer.rs
@@ -140,7 +140,7 @@ impl PyBuffer {
 impl TryFromBorrowedObject for PyBuffer {
     fn try_from_borrowed_object(vm: &VirtualMachine, obj: &PyObject) -> PyResult<Self> {
         let cls = obj.class();
-        if let Some(f) = cls.mro_find_map(|cls| cls.slots.as_buffer) {
+        if let Some(f) = cls.slots.as_buffer {
             return f(obj, vm);
         }
         Err(vm.new_type_error(format!(
diff --git a/vm/src/protocol/iter.rs b/vm/src/protocol/iter.rs
index deef0c37ea..eccb8a2075 100644
--- a/vm/src/protocol/iter.rs
+++ b/vm/src/protocol/iter.rs
@@ -16,9 +16,7 @@ where
 
 impl PyIter<PyObjectRef> {
     pub fn check(obj: &PyObject) -> bool {
-        obj.class()
-            .mro_find_map(|x| x.slots.iternext.load())
-            .is_some()
+        obj.class().slots.iternext.load().is_some()
     }
 }
 
@@ -34,7 +32,9 @@ where
             self.0
                 .borrow()
                 .class()
-                .mro_find_map(|x| x.slots.iternext.load())
+                .slots
+                .iternext
+                .load()
                 .ok_or_else(|| {
                     vm.new_type_error(format!(
                         "'{}' object is not an iterator",
@@ -120,7 +120,7 @@ impl TryFromObject for PyIter<PyObjectRef> {
     fn try_from_object(vm: &VirtualMachine, iter_target: PyObjectRef) -> PyResult<Self> {
         let getiter = {
             let cls = iter_target.class();
-            cls.mro_find_map(|x| x.slots.iter.load())
+            cls.slots.iter.load()
         };
         if let Some(getiter) = getiter {
             let iter = getiter(iter_target, vm)?;
diff --git a/vm/src/protocol/mapping.rs b/vm/src/protocol/mapping.rs
index f8ec7437d4..7ea7f0c63a 100644
--- a/vm/src/protocol/mapping.rs
+++ b/vm/src/protocol/mapping.rs
@@ -70,11 +70,7 @@ impl PyMapping<'_> {
 
     pub fn methods(&self, vm: &VirtualMachine) -> &PyMappingMethods {
         self.methods.get_or_init(|| {
-            if let Some(f) = self
-                .obj
-                .class()
-                .mro_find_map(|cls| cls.slots.as_mapping.load())
-            {
+            if let Some(f) = self.obj.class().slots.as_mapping.load() {
                 f(self.obj, vm)
             } else {
                 PyMappingMethods::default()
diff --git a/vm/src/protocol/object.rs b/vm/src/protocol/object.rs
index 5023eca11f..c56f067cd1 100644
--- a/vm/src/protocol/object.rs
+++ b/vm/src/protocol/object.rs
@@ -90,10 +90,7 @@ impl PyObject {
     #[inline]
     fn _get_attr(&self, attr_name: PyStrRef, vm: &VirtualMachine) -> PyResult {
         vm_trace!("object.__getattribute__: {:?} {:?}", obj, attr_name);
-        let getattro = self
-            .class()
-            .mro_find_map(|cls| cls.slots.getattro.load())
-            .unwrap();
+        let getattro = self.class().slots.getattro.load().unwrap();
         getattro(self, attr_name.clone(), vm).map_err(|exc| {
             vm.set_attribute_error_context(&exc, self.to_owned(), attr_name);
             exc
@@ -108,18 +105,17 @@ impl PyObject {
     ) -> PyResult<()> {
         let setattro = {
             let cls = self.class();
-            cls.mro_find_map(|cls| cls.slots.setattro.load())
-                .ok_or_else(|| {
-                    let assign = attr_value.is_some();
-                    let has_getattr = cls.mro_find_map(|cls| cls.slots.getattro.load()).is_some();
-                    vm.new_type_error(format!(
-                        "'{}' object has {} attributes ({} {})",
-                        cls.name(),
-                        if has_getattr { "only read-only" } else { "no" },
-                        if assign { "assign to" } else { "del" },
-                        attr_name
-                    ))
-                })?
+            cls.slots.setattro.load().ok_or_else(|| {
+                let assign = attr_value.is_some();
+                let has_getattr = cls.slots.getattro.load().is_some();
+                vm.new_type_error(format!(
+                    "'{}' object has {} attributes ({} {})",
+                    cls.name(),
+                    if has_getattr { "only read-only" } else { "no" },
+                    if assign { "assign to" } else { "del" },
+                    attr_name
+                ))
+            })?
         };
         setattro(self, attr_name, attr_value, vm)
     }
@@ -145,7 +141,7 @@ impl PyObject {
         vm_trace!("object.__setattr__({:?}, {}, {:?})", obj, attr_name, value);
 
         if let Some(attr) = self.get_class_attr(attr_name.as_str()) {
-            let descr_set = attr.class().mro_find_map(|cls| cls.slots.descr_set.load());
+            let descr_set = attr.class().slots.descr_set.load();
             if let Some(descriptor) = descr_set {
                 return descriptor(attr, self.to_owned(), value, vm);
             }
@@ -194,12 +190,9 @@ impl PyObject {
         let cls_attr = match obj_cls.get_attr(name) {
             Some(descr) => {
                 let descr_cls = descr.class();
-                let descr_get = descr_cls.mro_find_map(|cls| cls.slots.descr_get.load());
+                let descr_get = descr_cls.slots.descr_get.load();
                 if let Some(descr_get) = descr_get {
-                    if descr_cls
-                        .mro_find_map(|cls| cls.slots.descr_set.load())
-                        .is_some()
-                    {
+                    if descr_cls.slots.descr_set.load().is_some() {
                         drop(descr_cls);
                         let cls = obj_cls.into_owned().into();
                         return descr_get(descr, Some(self.to_owned()), Some(cls), vm).map(Some);
@@ -254,10 +247,7 @@ impl PyObject {
     ) -> PyResult<Either<PyObjectRef, bool>> {
         let swapped = op.swapped();
         let call_cmp = |obj: &PyObject, other: &PyObject, op| {
-            let cmp = obj
-                .class()
-                .mro_find_map(|cls| cls.slots.richcompare.load())
-                .unwrap();
+            let cmp = obj.class().slots.richcompare.load().unwrap();
             let r = match cmp(obj, other, op, vm)? {
                 Either::A(obj) => PyArithmeticValue::from_object(vm, obj).map(Either::A),
                 Either::B(arithmetic) => arithmetic.map(Either::B),
@@ -496,10 +486,7 @@ impl PyObject {
     }
 
     pub fn hash(&self, vm: &VirtualMachine) -> PyResult<PyHash> {
-        let hash = self
-            .class()
-            .mro_find_map(|cls| cls.slots.hash.load())
-            .unwrap(); // hash always exist
+        let hash = self.class().slots.hash.load().unwrap(); // hash always exist
         hash(self, vm)
     }
 
diff --git a/vm/src/protocol/sequence.rs b/vm/src/protocol/sequence.rs
index 94f3b1fa40..4696f2d87f 100644
--- a/vm/src/protocol/sequence.rs
+++ b/vm/src/protocol/sequence.rs
@@ -97,7 +97,7 @@ impl PySequence<'_> {
         self.methods.get_or_init(|| {
             let cls = self.obj.class();
             if !cls.is(&vm.ctx.types.dict_type) {
-                if let Some(f) = cls.mro_find_map(|x| x.slots.as_sequence.load()) {
+                if let Some(f) = cls.slots.as_sequence.load() {
                     return f(self.obj, vm);
                 }
             }
diff --git a/vm/src/sequence.rs b/vm/src/sequence.rs
index 798db58336..93c6f236c9 100644
--- a/vm/src/sequence.rs
+++ b/vm/src/sequence.rs
@@ -111,9 +111,7 @@ pub trait MutObjectSequenceOp<'a> {
         F: FnMut(),
     {
         let needle_cls = needle.class();
-        let needle_cmp = needle_cls
-            .mro_find_map(|cls| cls.slots.richcompare.load())
-            .unwrap();
+        let needle_cmp = needle_cls.slots.richcompare.load().unwrap();
 
         let mut borrower = None;
         let mut i = range.start;
@@ -146,9 +144,7 @@ pub trait MutObjectSequenceOp<'a> {
                     !elem_cls.is(&needle_cls) && elem_cls.fast_issubclass(&needle_cls);
 
                 let eq = if reverse_first {
-                    let elem_cmp = elem_cls
-                        .mro_find_map(|cls| cls.slots.richcompare.load())
-                        .unwrap();
+                    let elem_cmp = elem_cls.slots.richcompare.load().unwrap();
                     drop(elem_cls);
 
                     fn cmp(
@@ -195,9 +191,7 @@ pub trait MutObjectSequenceOp<'a> {
                             obj.try_to_bool(vm)?
                         }
                         _ => {
-                            let elem_cmp = elem_cls
-                                .mro_find_map(|cls| cls.slots.richcompare.load())
-                                .unwrap();
+                            let elem_cmp = elem_cls.slots.richcompare.load().unwrap();
                             drop(elem_cls);
 
                             fn cmp(
diff --git a/vm/src/types/slot.rs b/vm/src/types/slot.rs
index 449b0fc52e..91007c8b30 100644
--- a/vm/src/types/slot.rs
+++ b/vm/src/types/slot.rs
@@ -78,12 +78,52 @@ pub struct PyTypeSlots {
 }
 
 impl PyTypeSlots {
-    pub fn from_flags(flags: PyTypeFlags) -> Self {
+    pub fn with_flags(flags: PyTypeFlags) -> Self {
         Self {
             flags,
             ..Default::default()
         }
     }
+
+    pub fn inherits(&mut self, mro: &[&PyType]) {
+        macro_rules! inherit {
+            ($name:ident) => {
+                if self.$name.is_none() {
+                    for ty in mro {
+                        if let Some(func) = ty.slots.$name {
+                            self.$name = Some(func);
+                            break;
+                        }
+                    }
+                }
+            };
+            ($name:ident, "atomic") => {
+                if self.$name.load().is_none() {
+                    for ty in mro {
+                        if let Some(func) = ty.slots.$name.load() {
+                            self.$name.store(Some(func));
+                            break;
+                        }
+                    }
+                }
+            };
+        }
+        inherit!(as_sequence, "atomic");
+        inherit!(as_mapping, "atomic");
+        inherit!(hash, "atomic");
+        inherit!(call, "atomic");
+        inherit!(getattro, "atomic");
+        inherit!(setattro, "atomic");
+        inherit!(as_buffer);
+        inherit!(richcompare, "atomic");
+        inherit!(iter, "atomic");
+        inherit!(iternext, "atomic");
+        inherit!(descr_get, "atomic");
+        inherit!(descr_set, "atomic");
+        inherit!(init, "atomic");
+        inherit!(new, "atomic");
+        inherit!(del, "atomic");
+    }
 }
 
 impl std::fmt::Debug for PyTypeSlots {
diff --git a/vm/src/vm/method.rs b/vm/src/vm/method.rs
index de8e287472..3f905c2d4d 100644
--- a/vm/src/vm/method.rs
+++ b/vm/src/vm/method.rs
@@ -21,7 +21,7 @@ pub enum PyMethod {
 impl PyMethod {
     pub fn get(obj: PyObjectRef, name: PyStrRef, vm: &VirtualMachine) -> PyResult<Self> {
         let cls = obj.class();
-        let getattro = cls.mro_find_map(|cls| cls.slots.getattro.load()).unwrap();
+        let getattro = cls.slots.getattro.load().unwrap();
         if getattro as usize != PyBaseObject::getattro as usize {
             drop(cls);
             return obj.get_attr(name, vm).map(Self::Attribute);
@@ -36,12 +36,9 @@ impl PyMethod {
                     is_method = true;
                     None
                 } else {
-                    let descr_get = descr_cls.mro_find_map(|cls| cls.slots.descr_get.load());
+                    let descr_get = descr_cls.slots.descr_get.load();
                     if let Some(descr_get) = descr_get {
-                        if descr_cls
-                            .mro_find_map(|cls| cls.slots.descr_set.load())
-                            .is_some()
-                        {
+                        if descr_cls.slots.descr_set.load().is_some() {
                             drop(descr_cls);
                             let cls = cls.into_owned().into();
                             return descr_get(descr, Some(obj), Some(cls), vm).map(Self::Attribute);
diff --git a/vm/src/vm/mod.rs b/vm/src/vm/mod.rs
index 87e4ac22d8..300d4747dc 100644
--- a/vm/src/vm/mod.rs
+++ b/vm/src/vm/mod.rs
@@ -579,9 +579,7 @@ impl VirtualMachine {
     }
 
     pub fn is_callable(&self, obj: &PyObject) -> bool {
-        obj.class()
-            .mro_find_map(|cls| cls.slots.call.load())
-            .is_some()
+        obj.class().slots.call.load().is_some()
     }
 
     #[inline]
diff --git a/vm/src/vm/vm_object.rs b/vm/src/vm/vm_object.rs
index 4c98a4c08e..9a3d6125a6 100644
--- a/vm/src/vm/vm_object.rs
+++ b/vm/src/vm/vm_object.rs
@@ -91,7 +91,7 @@ impl VirtualMachine {
         obj: Option<PyObjectRef>,
         cls: Option<PyObjectRef>,
     ) -> Result<PyResult, PyObjectRef> {
-        let descr_get = descr.class().mro_find_map(|cls| cls.slots.descr_get.load());
+        let descr_get = descr.class().slots.descr_get.load();
         match descr_get {
             Some(descr_get) => Ok(descr_get(descr, obj, cls, self)),
             None => Err(descr),
@@ -164,7 +164,7 @@ impl VirtualMachine {
 
     fn _invoke(&self, callable: &PyObject, args: FuncArgs) -> PyResult {
         vm_trace!("Invoke: {:?} {:?}", callable, args);
-        let slot_call = callable.class().mro_find_map(|cls| cls.slots.call.load());
+        let slot_call = callable.class().slots.call.load();
         match slot_call {
             Some(slot_call) => {
                 self.trace_event(TraceEvent::Call)?;