Wrapped into a reference object to be modified when captured in a closure

编写代码的时候遇到这个报错“Wrapped into a reference object to be modified when captured in a closure”
没百度出结果，中文就是说“包裹到要在关闭中捕获时要修改的参考对象中”
下面的代码中，所有的fragflag常量都有警告，想请教各位讲一下原理。

问题代码如下：

class MainActivityRSC : AppCompatActivity() {
    override fun onCreate(savedInstanceState: Bundle?) {
        super.onCreate(savedInstanceState)
        setContentView(R.layout.activity_main_rsc)
        supportActionBar?.hide()
        var fragflag = 0          //这里fragflag警告：Typo: In word 'fragflag' 
        val buttonRSC0: Button = findViewById(R.id.RSC_General)
        val buttonRSC1: Button = findViewById(R.id.RSC_1)
        val buttonRSC11: Button = findViewById(R.id.RSC_MenuBack)


        buttonRSC0.setOnClickListener {
            if(fragflag != 0) {          //这里fragflag警告：Wrapped into a reference object to be modified when captured in a closure
                replaceFragment(RightFragRSC0())
                fragflag = 0          //这里fragflag警告：Wrapped into a reference object to be modified when captured in a closure
            }
        }
        buttonRSC1.setOnClickListener {
            if(fragflag != 1) {          //这里fragflag警告：Wrapped into a reference object to be modified when captured in a closure
                replaceFragment(RightFragRSC1())
                fragflag = 1          //这里fragflag警告：Wrapped into a reference object to be modified when captured in a closure
            }
        }
        buttonRSC11.setOnClickListener {
            val intent = Intent(this,MainActivity::class.java)
            startActivity(intent)
        }

        replaceFragment(RightFragRSC0())
    }


    private fun replaceFragment(fragment: Fragment) {
        val fragmentManager = supportFragmentManager
        val transaction = fragmentManager.beginTransaction()
        transaction.replace(R.id.rightLayout, fragment)
        transaction.commit()
    }
}