eslint-plugin-react-hooks version: 4.2.0

## Steps To Reproduce

I know it shouldn't exist in production code, but it's annoying while editing some files.

```js
import React, { useEffect } from "react";

const App = () => {
  useEffect(); // <-
  return null;
};

export default App;
```

Link to code example: https://codesandbox.io/s/polished-sun-3wr27?file=/src/App.js

## The current behavior

ESLint crashed.

```
TypeError: Cannot read property 'type' of undefined
```

## The expected behavior

ESLint doesn't crash but reports an error instead.
startTransition2();
            startTransition3();
            startTransition4();
            // Dynamic
            console.log(state1);
            console.log(state2);
            console.log(state3);
            console.log(state4);
            console.log(state5);
            console.log(state6);
            console.log(isPending2);
            console.log(isPending4);
            mySetState();
            myDispatch();
            // Not sure; assume dynamic
            maybeSetState();
            maybeDispatch();
          }, [
            // Dynamic
            state1, state2, state3, state4, state5, state6,
            maybeRef1, maybeRef2,
            isPending2, isPending4,
            // Not sure; assume dynamic
            mySetState, myDispatch,
            maybeSetState, maybeDispatch
            // In this test, we don't specify static deps.
            // That should be okay.
          ]);
        }
      `,