RustPython · youknowone · Mar 5, 2026 · Mar 3, 2026 · Mar 3, 2026 · Mar 3, 2026
diff --git a/.cspell.dict/rust-more.txt b/.cspell.dict/rust-more.txt
@@ -6,6 +6,7 @@ bindgen
 bitand
 bitflags
 bitor
+bitvec
 bitxor
 bstr
 byteorder
@@ -58,6 +59,7 @@ powi
 prepended
 punct
 replacen
+retag
 rmatch
 rposition
 rsplitn
@@ -89,5 +91,3 @@ widestring
 winapi
 winresource
 winsock
-bitvec
-Bitvec
diff --git a/Lib/test/test_dataclasses/__init__.py b/Lib/test/test_dataclasses/__init__.py
@@ -3672,7 +3672,6 @@ class A:
         self.assertEqual(obj.a, 'a')
         self.assertEqual(obj.b, 'b')
 
-    @unittest.expectedFailure  # TODO: RUSTPYTHON
     def test_slots_no_weakref(self):
         @dataclass(slots=True)
         class A:
@@ -3687,7 +3686,6 @@ class A:
         with self.assertRaises(AttributeError):
             a.__weakref__
 
-    @unittest.expectedFailure  # TODO: RUSTPYTHON
     def test_slots_weakref(self):
         @dataclass(slots=True, weakref_slot=True)
         class A:
@@ -3748,7 +3746,6 @@ def test_weakref_slot_make_dataclass(self):
                                     "weakref_slot is True but slots is False"):
             B = make_dataclass('B', [('a', int),], weakref_slot=True)
 
-    @unittest.expectedFailure  # TODO: RUSTPYTHON
     def test_weakref_slot_subclass_weakref_slot(self):
         @dataclass(slots=True, weakref_slot=True)
         class Base:
@@ -3767,7 +3764,6 @@ class A(Base):
         a_ref = weakref.ref(a)
         self.assertIs(a.__weakref__, a_ref)
 
-    @unittest.expectedFailure  # TODO: RUSTPYTHON
     def test_weakref_slot_subclass_no_weakref_slot(self):
         @dataclass(slots=True, weakref_slot=True)
         class Base:
@@ -3785,7 +3781,6 @@ class A(Base):
         a_ref = weakref.ref(a)
         self.assertIs(a.__weakref__, a_ref)
 
-    @unittest.expectedFailure  # TODO: RUSTPYTHON
     def test_weakref_slot_normal_base_weakref_slot(self):
         class Base:
             __slots__ = ('__weakref__',)
@@ -3830,7 +3825,6 @@ class B[T2]:
         self.assertTrue(B.__weakref__)
         B()
 
-    @unittest.expectedFailure  # TODO: RUSTPYTHON
     def test_dataclass_derived_generic_from_base(self):
         T = typing.TypeVar('T')
 

diff --git a/Lib/test/test_descr.py b/Lib/test/test_descr.py
@@ -1321,7 +1321,6 @@ class X(object):
         with self.assertRaisesRegex(AttributeError, "'X' object has no attribute 'a'"):
             X().a
 
-    @unittest.expectedFailure  # TODO: RUSTPYTHON
     def test_slots_special(self):
         # Testing __dict__ and __weakref__ in __slots__...
         class D(object):
@@ -2294,7 +2293,6 @@ def __contains__(self, value):
             self.assertIn(i, p10)
         self.assertNotIn(10, p10)
 
-    @unittest.expectedFailure  # TODO: RUSTPYTHON
     def test_weakrefs(self):
         # Testing weak references...
         import weakref
@@ -3976,7 +3974,6 @@ def __init__(self, x):
             o = trash(o)
         del o
 
-    @unittest.expectedFailure  # TODO: RUSTPYTHON
     def test_slots_multiple_inheritance(self):
         # SF bug 575229, multiple inheritance w/ slots dumps core
         class A(object):

diff --git a/Lib/test/test_weakref.py b/Lib/test/test_weakref.py
@@ -1862,7 +1862,6 @@ def test_weak_valued_delitem(self):
         self.assertEqual(len(d), 1)
         self.assertEqual(list(d.items()), [('something else', o2)])
 
-    @unittest.expectedFailure  # TODO: RUSTPYTHON
     def test_weak_keyed_bad_delitem(self):
         d = weakref.WeakKeyDictionary()
         o = Object('1')

diff --git a/crates/stdlib/src/_asyncio.rs b/crates/stdlib/src/_asyncio.rs
@@ -160,7 +160,7 @@ pub(crate) mod _asyncio {
     }
 
     #[pyclass(
-        flags(BASETYPE, HAS_DICT),
+        flags(BASETYPE, HAS_DICT, HAS_WEAKREF),
         with(Constructor, Initializer, Destructor, Representable, Iterable)
     )]
     impl PyFuture {
@@ -1169,7 +1169,7 @@ pub(crate) mod _asyncio {
     }
 
     #[pyclass(
-        flags(BASETYPE, HAS_DICT),
+        flags(BASETYPE, HAS_DICT, HAS_WEAKREF),
         with(Constructor, Initializer, Destructor, Representable, Iterable)
     )]
     impl PyTask {

diff --git a/crates/stdlib/src/_sqlite3.rs b/crates/stdlib/src/_sqlite3.rs
@@ -976,7 +976,7 @@ mod _sqlite3 {
         }
     }
 
-    #[pyclass(with(Constructor, Callable, Initializer), flags(BASETYPE))]
+    #[pyclass(with(Constructor, Callable, Initializer), flags(BASETYPE, HAS_WEAKREF))]
     impl Connection {
         fn drop_db(&self) {
             self.db.lock().take();
@@ -1629,7 +1629,10 @@ mod _sqlite3 {
         size: Option<c_int>,
     }
 
-    #[pyclass(with(Constructor, Initializer, IterNext, Iterable), flags(BASETYPE))]
+    #[pyclass(
+        with(Constructor, Initializer, IterNext, Iterable),
+        flags(BASETYPE, HAS_WEAKREF)
+    )]
     impl Cursor {
         fn new(
             connection: PyRef<Connection>,

diff --git a/crates/stdlib/src/array.rs b/crates/stdlib/src/array.rs
@@ -698,7 +698,7 @@ mod array {
     }
 
     #[pyclass(
-        flags(BASETYPE),
+        flags(BASETYPE, HAS_WEAKREF),
         with(
             Comparable,
             AsBuffer,

diff --git a/crates/stdlib/src/mmap.rs b/crates/stdlib/src/mmap.rs
@@ -851,7 +851,7 @@ mod mmap {
 
     #[pyclass(
         with(Constructor, AsMapping, AsSequence, AsBuffer, Representable),
-        flags(BASETYPE)
+        flags(BASETYPE, HAS_WEAKREF)
     )]
     impl PyMmap {
         fn as_bytes_mut(&self) -> BorrowedValueMut<'_, [u8]> {

diff --git a/crates/stdlib/src/re.rs b/crates/stdlib/src/re.rs
@@ -317,7 +317,7 @@ mod re {
     #[pyfunction]
     fn purge(_vm: &VirtualMachine) {}
 
-    #[pyclass]
+    #[pyclass(flags(HAS_WEAKREF))]
     impl PyPattern {
         #[pymethod(name = "match")]
         fn match_(&self, text: PyStrRef) -> Option<PyMatch> {

diff --git a/crates/vm/src/builtins/asyncgenerator.rs b/crates/vm/src/builtins/asyncgenerator.rs
@@ -40,7 +40,10 @@ impl PyPayload for PyAsyncGen {
     }
 }
 
-#[pyclass(flags(DISALLOW_INSTANTIATION), with(PyRef, Representable, Destructor))]
+#[pyclass(
+    flags(DISALLOW_INSTANTIATION, HAS_WEAKREF),
+    with(PyRef, Representable, Destructor)
+)]
 impl PyAsyncGen {
     pub const fn as_coro(&self) -> &Coro {
         &self.inner

diff --git a/crates/vm/src/builtins/builtin_func.rs b/crates/vm/src/builtins/builtin_func.rs
@@ -16,6 +16,8 @@ pub struct PyNativeFunction {
     pub(crate) value: &'static PyMethodDef,
     pub(crate) zelf: Option<PyObjectRef>,
     pub(crate) module: Option<&'static PyStrInterned>, // None for bound method
+    /// Prevent HeapMethodDef from being freed while this function references it
+    pub(crate) _method_def_owner: Option<PyObjectRef>,
 }
 
 impl PyPayload for PyNativeFunction {
@@ -126,7 +128,7 @@ impl Representable for PyNativeFunction {
 
 #[pyclass(
     with(Callable, Comparable, Representable),
-    flags(HAS_DICT, DISALLOW_INSTANTIATION)
+    flags(HAS_DICT, HAS_WEAKREF, DISALLOW_INSTANTIATION)
 )]
 impl PyNativeFunction {
     #[pygetset]
@@ -210,7 +212,7 @@ pub struct PyNativeMethod {
 // All Python-visible behavior (getters, slots) is registered by PyNativeFunction::extend_class.
 // PyNativeMethod only extends the Rust-side struct with the defining class reference.
 // The func field at offset 0 (#[repr(C)]) allows NativeFunctionOrMethod to read it safely.
-#[pyclass(flags(HAS_DICT, DISALLOW_INSTANTIATION))]
+#[pyclass(flags(HAS_DICT, HAS_WEAKREF, DISALLOW_INSTANTIATION))]
 impl PyNativeMethod {}
 
 impl fmt::Debug for PyNativeMethod {

diff --git a/crates/vm/src/builtins/classmethod.rs b/crates/vm/src/builtins/classmethod.rs
@@ -125,7 +125,7 @@ impl PyClassMethod {
 
 #[pyclass(
     with(GetDescriptor, Constructor, Initializer, Representable),
-    flags(BASETYPE, HAS_DICT)
+    flags(BASETYPE, HAS_DICT, HAS_WEAKREF)
 )]
 impl PyClassMethod {
     #[pygetset]

diff --git a/crates/vm/src/builtins/code.rs b/crates/vm/src/builtins/code.rs
@@ -597,7 +597,7 @@ impl Constructor for PyCode {
     }
 }
 
-#[pyclass(with(Representable, Constructor))]
+#[pyclass(with(Representable, Constructor), flags(HAS_WEAKREF))]
 impl PyCode {
     #[pygetset]
     const fn co_posonlyargcount(&self) -> usize {

diff --git a/crates/vm/src/builtins/coroutine.rs b/crates/vm/src/builtins/coroutine.rs
@@ -32,7 +32,7 @@ impl PyPayload for PyCoroutine {
 }
 
 #[pyclass(
-    flags(DISALLOW_INSTANTIATION),
+    flags(DISALLOW_INSTANTIATION, HAS_WEAKREF),
     with(Py, IterNext, Representable, Destructor)
 )]
 impl PyCoroutine {

diff --git a/crates/vm/src/builtins/descriptor.rs b/crates/vm/src/builtins/descriptor.rs
@@ -37,6 +37,8 @@ pub struct PyMethodDescriptor {
     pub method: &'static PyMethodDef,
     // vectorcall: vector_call_func,
     pub objclass: &'static Py<PyType>, // TODO: move to tp_members
+    /// Prevent HeapMethodDef from being freed while this descriptor references it
+    pub(crate) _method_def_owner: Option<PyObjectRef>,
 }
 
 impl PyMethodDescriptor {
@@ -49,6 +51,7 @@ impl PyMethodDescriptor {
             },
             method,
             objclass: typ,
+            _method_def_owner: None,
         }
     }
 }
@@ -88,13 +91,12 @@ impl GetDescriptor for PyMethodDescriptor {
                 } else if descr.method.flags.contains(PyMethodFlags::CLASS) {
                     obj.class().to_owned().into()
                 } else {
-                    unimplemented!()
+                    obj
                 }
             }
             None if descr.method.flags.contains(PyMethodFlags::CLASS) => cls.unwrap(),
             None => return Ok(zelf),
         };
-        // Ok(descr.method.build_bound_method(&vm.ctx, bound, class).into())
         Ok(descr.bind(bound, &vm.ctx).into())
     }
 }

diff --git a/crates/vm/src/builtins/function.rs b/crates/vm/src/builtins/function.rs
@@ -717,7 +717,7 @@ impl PyPayload for PyFunction {
 
 #[pyclass(
     with(GetDescriptor, Callable, Representable, Constructor),
-    flags(HAS_DICT, METHOD_DESCRIPTOR)
+    flags(HAS_DICT, HAS_WEAKREF, METHOD_DESCRIPTOR)
 )]
 impl PyFunction {
     #[pygetset]
@@ -1170,7 +1170,7 @@ impl PyBoundMethod {
 
 #[pyclass(
     with(Callable, Comparable, GetAttr, Constructor, Representable),
-    flags(IMMUTABLETYPE)
+    flags(IMMUTABLETYPE, HAS_WEAKREF)
 )]
 impl PyBoundMethod {
     #[pymethod]

diff --git a/crates/vm/src/builtins/generator.rs b/crates/vm/src/builtins/generator.rs
@@ -34,7 +34,7 @@ impl PyPayload for PyGenerator {
 }
 
 #[pyclass(
-    flags(DISALLOW_INSTANTIATION),
+    flags(DISALLOW_INSTANTIATION, HAS_WEAKREF),
     with(Py, IterNext, Iterable, Representable, Destructor)
 )]
 impl PyGenerator {

diff --git a/crates/vm/src/builtins/genericalias.rs b/crates/vm/src/builtins/genericalias.rs
@@ -84,7 +84,7 @@ impl Constructor for PyGenericAlias {
         Iterable,
         Representable
     ),
-    flags(BASETYPE)
+    flags(BASETYPE, HAS_WEAKREF)
 )]
 impl PyGenericAlias {
     pub fn new(

diff --git a/crates/vm/src/builtins/memory.rs b/crates/vm/src/builtins/memory.rs
@@ -549,7 +549,7 @@ impl Py<PyMemoryView> {
         Iterable,
         Representable
     ),
-    flags(SEQUENCE)
+    flags(SEQUENCE, HAS_WEAKREF)
 )]
 impl PyMemoryView {
     #[pyclassmethod]

diff --git a/crates/vm/src/builtins/module.rs b/crates/vm/src/builtins/module.rs
@@ -286,7 +286,10 @@ impl Py<PyModule> {
     }
 }
 
-#[pyclass(with(GetAttr, Initializer, Representable), flags(BASETYPE, HAS_DICT))]
+#[pyclass(
+    with(GetAttr, Initializer, Representable),
+    flags(BASETYPE, HAS_DICT, HAS_WEAKREF)
+)]
 impl PyModule {
     #[pyslot]
     fn slot_new(cls: PyTypeRef, _args: FuncArgs, vm: &VirtualMachine) -> PyResult {

diff --git a/crates/vm/src/builtins/namespace.rs b/crates/vm/src/builtins/namespace.rs
@@ -28,7 +28,7 @@ impl PyPayload for PyNamespace {
 impl DefaultConstructor for PyNamespace {}
 
 #[pyclass(
-    flags(BASETYPE, HAS_DICT),
+    flags(BASETYPE, HAS_DICT, HAS_WEAKREF),
     with(Constructor, Initializer, Comparable, Representable)
 )]
 impl PyNamespace {

diff --git a/crates/vm/src/builtins/object.rs b/crates/vm/src/builtins/object.rs
@@ -464,6 +464,8 @@ impl PyBaseObject {
                 if both_mutable || both_module {
                     let has_dict =
                         |typ: &Py<PyType>| typ.slots.flags.has_feature(PyTypeFlags::HAS_DICT);
+                    let has_weakref =
+                        |typ: &Py<PyType>| typ.slots.flags.has_feature(PyTypeFlags::HAS_WEAKREF);
                     // Compare slots tuples
                     let slots_equal = match (
                         current_cls
@@ -484,6 +486,8 @@ impl PyBaseObject {
                     if current_cls.slots.basicsize != cls.slots.basicsize
                         || !slots_equal
                         || has_dict(current_cls) != has_dict(&cls)
+                        || has_weakref(current_cls) != has_weakref(&cls)
+                        || current_cls.slots.member_count != cls.slots.member_count
                     {
                         return Err(vm.new_type_error(format!(
                             "__class__ assignment: '{}' object layout differs from '{}'",

diff --git a/crates/vm/src/builtins/property.rs b/crates/vm/src/builtins/property.rs
@@ -65,7 +65,10 @@ impl GetDescriptor for PyProperty {
     }
 }
 
-#[pyclass(with(Constructor, Initializer, GetDescriptor), flags(BASETYPE))]
+#[pyclass(
+    with(Constructor, Initializer, GetDescriptor),
+    flags(BASETYPE, HAS_WEAKREF)
+)]
 impl PyProperty {
     // Helper method to get property name
     // Returns the name if available, None if not found, or propagates errors

diff --git a/crates/vm/src/builtins/set.rs b/crates/vm/src/builtins/set.rs
@@ -531,7 +531,7 @@ fn reduce_set(
         AsNumber,
         Representable
     ),
-    flags(BASETYPE, _MATCH_SELF)
+    flags(BASETYPE, _MATCH_SELF, HAS_WEAKREF)
 )]
 impl PySet {
     fn __len__(&self) -> usize {
@@ -996,7 +996,7 @@ impl Constructor for PyFrozenSet {
 }
 
 #[pyclass(
-    flags(BASETYPE, _MATCH_SELF),
+    flags(BASETYPE, _MATCH_SELF, HAS_WEAKREF),
     with(
         Constructor,
         AsSequence,

diff --git a/crates/vm/src/builtins/staticmethod.rs b/crates/vm/src/builtins/staticmethod.rs
@@ -88,7 +88,7 @@ impl Initializer for PyStaticMethod {
 
 #[pyclass(
     with(Callable, GetDescriptor, Constructor, Initializer, Representable),
-    flags(BASETYPE, HAS_DICT)
+    flags(BASETYPE, HAS_DICT, HAS_WEAKREF)
 )]
 impl PyStaticMethod {
     #[pygetset]