Function make_parameters_from_slice

crates/vm/src/builtins/genericalias.rs:299–339

(args: &[PyObjectRef], vm: &VirtualMachine)

}

fn make_parameters_from_slice(args: &[PyObjectRef], vm: &VirtualMachine) -> PyTupleRef {
    let mut parameters: Vec<PyObjectRef> = Vec::with_capacity(args.len());

    for arg in args {
        // We don't want __parameters__ descriptor of a bare Python class.
        if arg.class().is(vm.ctx.types.type_type) {
            continue;
        }

        // Check for __typing_subst__ attribute
        if arg.get_attr(identifier!(vm, __typing_subst__), vm).is_ok() {
            if tuple_index(&parameters, arg).is_none() {
                parameters.push(arg.clone());
            }
        } else if let Ok(subparams) = arg.get_attr(identifier!(vm, __parameters__), vm)
            && let Ok(sub_params) = subparams.try_to_ref::<PyTuple>(vm)
        {
            for sub_param in sub_params {
                if tuple_index(&parameters, sub_param).is_none() {
                    parameters.push(sub_param.clone());
                }
            }
        } else if arg.try_to_ref::<PyTuple>(vm).is_ok() || arg.try_to_ref::<PyList>(vm).is_ok() {
            // Recursively extract parameters from lists/tuples (ParamSpec args)
            let items: Vec<PyObjectRef> = if let Ok(t) = arg.try_to_ref::<PyTuple>(vm) {
                t.as_slice().to_vec()
            } else {
                let list = arg.downcast_ref::<PyList>().unwrap();
                list.borrow_vec().to_vec()
            };
            let sub = make_parameters_from_slice(&items, vm);
            for sub_param in sub.iter() {
                if tuple_index(&parameters, sub_param).is_none() {
                    parameters.push(sub_param.clone());
                }
            }
        }
    }

    PyTuple::new_ref(parameters, &vm.ctx)
}

#[inline]
fn tuple_index(vec: &[PyObjectRef], item: &PyObject) -> Option<usize> {