inherit basicsize from the base type

Snowapril · Snowapril · commit d3e7b315e1b9 · 2024-05-18T17:42:57.000+09:00
diff --git a/vm/src/builtins/type.rs b/vm/src/builtins/type.rs
@@ -205,6 +205,9 @@ impl PyType {
         if base.slots.flags.has_feature(PyTypeFlags::HAS_DICT) {
             slots.flags |= PyTypeFlags::HAS_DICT
         }
+        if slots.basicsize == 0 {
+            slots.basicsize = base.slots.basicsize;
+        }
 
         if let Some(qualname) = attrs.get(identifier!(ctx, __qualname__)) {
             if !qualname.fast_isinstance(ctx.types.str_type) {
@@ -253,6 +256,9 @@ impl PyType {
         if base.slots.flags.has_feature(PyTypeFlags::HAS_DICT) {
             slots.flags |= PyTypeFlags::HAS_DICT
         }
+        if slots.basicsize == 0 {
+            slots.basicsize = base.slots.basicsize;
+        }
 
         let bases = vec![base.clone()];
         let mro = base.iter_mro().map(|x| x.to_owned()).collect();
