fix

youknowone · youknowone · commit 51794e412685 · 2025-07-13T00:36:18.000+09:00
diff --git a/extra_tests/snippets/builtin_type.py b/extra_tests/snippets/builtin_type.py
@@ -595,3 +595,10 @@ def my_repr_func():
 
 # https://github.com/RustPython/RustPython/issues/3100
 assert issubclass(types.BuiltinMethodType, types.BuiltinFunctionType)
+
+assert type.__dict__['__dict__'].__objclass__ is type
+assert type(type(type.__dict__['__dict__']).__objclass__).__name__ == 'member_descriptor'
+
+class A(type): pass
+
+assert '__dict__' not in A.__dict__
diff --git a/vm/src/builtins/type.rs b/vm/src/builtins/type.rs
@@ -936,9 +936,9 @@ impl Constructor for PyType {
             return Err(vm.new_value_error("type name must not contain null characters"));
         }
 
-        let (metatype, base, bases) = if bases.is_empty() {
+        let (metatype, base, bases, base_is_type) = if bases.is_empty() {
             let base = vm.ctx.types.object_type.to_owned();
-            (metatype, base.clone(), vec![base])
+            (metatype, base.clone(), vec![base], false)
         } else {
             let bases = bases
                 .iter()
@@ -972,8 +972,9 @@ impl Constructor for PyType {
             };
 
             let base = best_base(&bases, vm)?;
+            let base_is_type = base.is(vm.ctx.types.type_type);
 
-            (metatype, base.to_owned(), bases)
+            (metatype, base.to_owned(), bases, base_is_type)
         };
 
         let qualname = dict
@@ -1114,12 +1115,16 @@ impl Constructor for PyType {
             // All *classes* should have a dict. Exceptions are *instances* of
             // classes that define __slots__ and instances of built-in classes
             // (with exceptions, e.g function)
-            let __dict__ = identifier!(vm, __dict__);
-            attributes.entry(__dict__).or_insert_with(|| unsafe {
-                vm.ctx
-                    .new_getset("__dict__", &typ, subtype_get_dict, subtype_set_dict)
-                    .into()
-            });
+            // Also, type subclasses don't need their own __dict__ descriptor
+            // since they inherit it from type
+            if !base_is_type {
+                let __dict__ = identifier!(vm, __dict__);
+                attributes.entry(__dict__).or_insert_with(|| unsafe {
+                    vm.ctx
+                        .new_getset("__dict__", &typ, subtype_get_dict, subtype_set_dict)
+                        .into()
+                });
+            }
 
             if let Some(cell) = attributes.get(identifier!(vm, __classcell__)) {
                 let cell = PyCellRef::try_from_object(vm, cell.clone()).map_err(|_| {
