__doc__ handing in the right way

Author: youknowone

Lib/test/test_typing.py

@@ -5269,7 +5269,6 @@ def test_weakref_all(self):
         for t in things:
             self.assertEqual(weakref.ref(t)(), t)
 
-    @unittest.expectedFailure # TODO: RUSTPYTHON
     def test_parameterized_slots(self):
         T = TypeVar('T')
         class C(Generic[T]):
@@ -5289,7 +5288,6 @@ def foo(x: C['C']): ...
         self.assertEqual(get_type_hints(foo, globals(), locals())['x'], C[C])
         self.assertEqual(copy(C[int]), deepcopy(C[int]))
 
-    @unittest.expectedFailure # TODO: RUSTPYTHON
     def test_parameterized_slots_dict(self):
         T = TypeVar('T')
         class D(Generic[T]):

crates/codegen/src/compile.rs

@@ -2679,10 +2679,12 @@ impl Compiler {
         let qualname_name = self.name("__qualname__");
         emit!(self, Instruction::StoreLocal(qualname_name));
 
-        // Store __doc__
-        self.load_docstring(doc_str);
-        let doc = self.name("__doc__");
-        emit!(self, Instruction::StoreLocal(doc));
+        // Store __doc__ only if there's an explicit docstring
+        if let Some(doc) = doc_str {
+            self.emit_load_const(ConstantData::Str { value: doc.into() });
+            let doc_name = self.name("__doc__");
+            emit!(self, Instruction::StoreLocal(doc_name));
+        }
 
         // Store __firstlineno__ (new in Python 3.12+)
         self.emit_load_const(ConstantData::Integer {
@@ -2876,17 +2878,6 @@ impl Compiler {
         self.store_name(name)
     }
 
-    fn load_docstring(&mut self, doc_str: Option<String>) {
-        // TODO: __doc__ must be default None and no bytecode unless it is Some
-        // Duplicate top of stack (the function or class object)
-
-        // Doc string value:
-        self.emit_load_const(match doc_str {
-            Some(doc) => ConstantData::Str { value: doc.into() },
-            None => ConstantData::None, // set docstring None if not declared
-        });
-    }
-
     fn compile_while(&mut self, test: &Expr, body: &[Stmt], orelse: &[Stmt]) -> CompileResult<()> {
         let while_block = self.new_block();
         let else_block = self.new_block();

crates/vm/src/builtins/type.rs

@@ -1199,10 +1199,9 @@ impl Constructor for PyType {
                     });
 
                 let attr_name = vm.ctx.intern_str(member.to_string());
-                if !typ.has_attr(attr_name) {
-                    typ.set_attr(attr_name, member_descriptor.into());
-                }
-
+                // __slots__ attributes always get a member descriptor
+                // (this overrides any inherited attribute from MRO)
+                typ.set_attr(attr_name, member_descriptor.into());
                 offset += 1;
             }
         }