fix: allow module __class__ reassignment with matching layout

Copilot · youknowone · Copilot · commit 9376bcd247fc · 2025-12-25T16:43:53.000Z
Co-authored-by: youknowone &lt;69878+youknowone@users.noreply.github.com&gt;
diff --git a/crates/vm/src/builtins/object.rs b/crates/vm/src/builtins/object.rs
@@ -520,8 +520,6 @@ impl PyBaseObject {
                     if current_cls.slots.basicsize != cls.slots.basicsize
                         || current_cls.slots.member_count != cls.slots.member_count
                         || has_dict(current_cls) != has_dict(&cls)
-                        || (cls.slots.flags.has_feature(PyTypeFlags::HEAPTYPE)
-                            && instance.typeid() != PyBaseObject::payload_type_id())
                     {
                         return Err(vm.new_type_error(format!(
                             "__class__ assignment: '{}' object layout differs from '{}'",

Original file line number	Diff line number	Diff line change
`@@ -520,8 +520,6 @@ impl PyBaseObject {`
`520`	`520`	`if current_cls.slots.basicsize != cls.slots.basicsize`
`521`	`521`	`\|\| current_cls.slots.member_count != cls.slots.member_count`
`522`	`522`	`\|\| has_dict(current_cls) != has_dict(&cls)`
`523`		`- \|\| (cls.slots.flags.has_feature(PyTypeFlags::HEAPTYPE)`
`524`		`- && instance.typeid() != PyBaseObject::payload_type_id())`
`525`	`523`	`{`
`526`	`524`	`return Err(vm.new_type_error(format!(`
`527`	`525`	`"__class__ assignment: '{}' object layout differs from '{}'",`