Fix _typing.override

Author: youknowone

Lib/test/test_typing.py

@@ -3351,8 +3351,6 @@ def x(self): ...
         self.assertNotIsSubclass(C, Protocol)
         self.assertNotIsInstance(C(), Protocol)
 
-    # TODO: RUSTPYTHON
-    @unittest.expectedFailure
     def test_protocols_issubclass_non_callable(self):
         class C:
             x = 1
@@ -3412,8 +3410,6 @@ def __init__(self) -> None:
         ):
             issubclass(Eggs, Spam)
 
-    # TODO: RUSTPYTHON
-    @unittest.expectedFailure
     def test_no_weird_caching_with_issubclass_after_isinstance_2(self):
         @runtime_checkable
         class Spam(Protocol):
@@ -3434,8 +3430,6 @@ class Eggs: ...
         ):
             issubclass(Eggs, Spam)
 
-    # TODO: RUSTPYTHON
-    @unittest.expectedFailure
     def test_no_weird_caching_with_issubclass_after_isinstance_3(self):
         @runtime_checkable
         class Spam(Protocol):

vm/src/stdlib/typing.rs

@@ -48,7 +48,10 @@ pub(crate) mod decl {
     #[pyfunction(name = "override")]
     pub(crate) fn r#override(func: PyObjectRef, vm: &VirtualMachine) -> PyResult {
         // Set __override__ attribute to True
-        func.set_attr("__override__", vm.ctx.true_value.clone(), vm)?;
+        // Skip the attribute silently if it is not writable.
+        // AttributeError happens if the object has __slots__ or a
+        // read-only property, TypeError if it's a builtin class.
+        let _ = func.set_attr("__override__", vm.ctx.true_value.clone(), vm);
         Ok(func)
     }