Shadow view with tag warnings

App.js

import React, { Component } from 'react';
import { Button, Text, TextInput, View } from 'react-native'
import { StackNavigator, NavigationActions } from 'react-navigation'

class MainScreen extends React.Component {
  componentWillMount () {
    this.props.navigation.setParams({asdf: 1234})
  }

  render () {
    const { navigation } = this.props

    return (
      <View style={{flex: 1, alignItems: 'center', justifyContent: 'center'}}>
        <Text style={{fontSize: 36}}>Main</Text>
        <Button title='Login' onPress={() => navigation.navigate('Login')} />
      </View>
    )
  }
}

const LoginScreen = (props) => {
  return (
    <View style={{flex: 1, alignItems: 'center', justifyContent: 'center'}}>
      <Text style={{fontSize: 36}}>Login</Text>
      <TextInput style={{width: 200, borderWidth: 1}} value='Hello' />
      <TextInput style={{width: 200, borderWidth: 1}} value='World' />
      <Button title='Done' onPress={() => {
        props.navigation.dispatch(NavigationActions.reset({
          index: 0,
          actions: [NavigationActions.navigate({ routeName: 'Main' })]
        }))
      }} />
    </View>
  )
}

const ModalStack = StackNavigator({
  Main: { screen: MainScreen },
  Login: { screen: LoginScreen },
})

export default class App extends Component<{}> {
  render() {
    return <ModalStack />
  }
}