Function _abc_instancecheck

crates/vm/src/stdlib/_abc.rs:246–284

(
        cls: PyObjectRef,
        instance: PyObjectRef,
        vm: &VirtualMachine,
    )

    /// Internal ABC helper for instance checks. Should be never used outside abc module.
    #[pyfunction]
    fn _abc_instancecheck(
        cls: PyObjectRef,
        instance: PyObjectRef,
        vm: &VirtualMachine,
    ) -> PyResult<PyObjectRef> {
        let impl_data = get_impl(&cls, vm)?;

        // Get instance.__class__
        let subclass = instance.get_attr("__class__", vm)?;

        // Check cache
        if in_weak_set(&impl_data.cache, &subclass, vm)? {
            return Ok(vm.ctx.true_value.clone().into());
        }

        let subtype: PyObjectRef = instance.class().to_owned().into();
        if subtype.is(&subclass) {
            let invalidation_counter = get_invalidation_counter();
            if impl_data.get_cache_version() == invalidation_counter
                && in_weak_set(&impl_data.negative_cache, &subclass, vm)?
            {
                return Ok(vm.ctx.false_value.clone().into());
            }
            // Fall back to __subclasscheck__
            return vm.call_method(&cls, "__subclasscheck__", (subclass,));
        }

        // Call __subclasscheck__ on subclass
        let result = vm.call_method(&cls, "__subclasscheck__", (subclass.clone(),))?;

        match result.clone().try_to_bool(vm) {
            Ok(true) => Ok(result),
            Ok(false) => {
                // Also try with subtype
                vm.call_method(&cls, "__subclasscheck__", (subtype,))
            }
            Err(e) => Err(e),
        }
    }

    /// Check if subclass is in registry (recursive)
    fn subclasscheck_check_registry(