Bug: typegen causes type error when a `service` is a function returning a StateMachine which has Context

[Jared Luxenberg]

Description

When an entry in the services part of the machine definition is a function returning a state machine which has context, I get a type error.

Consider the following machine defintions:

import { createMachine, assign, interpret } from "xstate";


export const childMachineWithContext = createMachine(
    {
      tsTypes: {} as import("./index.typegen").Typegen0,
      id: "Child Machine",
      initial: "initial",
      context: {count: 0},
      states: {
        initial: {
            entry: (context, event) => {console.log("in child machine", context.count)}
        },
      },
      schema: {context: {} as {count: number}},
      predictableActionArguments: true,
      preserveActionOrder: true,
    }
  );
  
  export const childMachineWithoutContext = createMachine(
    {
      tsTypes: {} as import("./index.typegen").Typegen1,
      id: "Child Machine",
      initial: "initial",
      states: {
        initial: {
            entry: (context, event) => {console.log("in child machine")}            
        },
      },
      predictableActionArguments: true,
      preserveActionOrder: true,
    }
  );
  


export const machine = createMachine(
  {
    tsTypes: {} as import("./index.typegen").Typegen2 ,
    id: "Parent Machine",
    initial: "initial",
    states: {
      initial: {
        invoke: {src: 'invoke child machine'},
      },
    },
    predictableActionArguments: true,
    preserveActionOrder: true,
  },
  {
    services: {
        'invoke child machine': (_context, _event) => childMachineWithContext
    },
    guards: {},
    delays: {},
  },
);


// start machine 
const service = interpret(machine).onTransition((state) => {
    console.log("interpret", state.value);
});  
  
service.start();

Expected result

There should be no error on the "invoke child machine" service binding line.

Actual result

There is an error:

Reproduction

Unfortunately, I can't do that because typegen doesn't run in CodeSandbox.

Additional context

NOTE: The error only happens if the child state machine has context and is instantiated via a function.

This works:

        'invoke child machine': childMachineWithContext

and this works:

        'invoke child machine': (_context, _event) => childMachineWithoutContext

Tested with XState version 4.38.2