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.
}
}
function getNodeWithoutReactNamespace(node, options) {
  if (
    node.type === 'MemberExpression' &&
    node.object.type === 'Identifier' &&
    node.object.name === 'React' &&
    node.property.type === 'Identifier' &&
    !node.computed
  ) {
    return node.property;
  }
  return node;
}
function getReactiveHookCallbackIndex(calleeNode, options) {
  const node = getNodeWithoutReactNamespace(calleeNode);
  if (node.type !== 'Identifier') {
    return -1;
  }
  switch (node.name) {
    case 'useEffect':
    case 'useLayoutEffect':
    case 'useCallback':
    case 'useMemo':
      
      return 0;
    case 'useImperativeHandle':
      
      return 1;
    default: