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kotlinlang

Can anybody think why this resolves to type `Any?` instead of `Number?`
```
fun String.toNumber(): Number? = toIntOrNull() ?: toLongOrNull() ?: toBigIntegerOrNull()
```

Inference bug? Since it doesn't complain when you define it explicitly.

I'd Imagine it has something to do with `Int`, `Long` inheriting from kotlin's `Number`, which does not inherit from java's, which `BigInteger` does.

but as you pointed out. `BigInteger("123") is Number` resolves to true, and I have no idea why that is

BTW, you can fix the line above by putting `as Number?` after `toLongOrNull()`. (Not after `toBigIntegerOrNull()` as you might expect.)

I think Int and Long inherits from Kotlin's Number but whereas Biginteger Inherits from Java Number class. Therefore theyare 2 different classes. Hence it resolves to Any

<@UB598EG6L> Please check your ' is' check. That must have imported from Java Number so its returning true

No, it's not. Without any import, `BigInteger("123") is kotlin.Number` returns `true`. It is a great mystery to me why that is, but it is. See here: <https://pl.kotl.in/32qL74dYR>

<@UKDCVK9JT> maybe you posted the wrong snippet? That code seems about a totally different topic…. (the operator get() trick is so cool, btw! :wink: )

<@UKDCVK9JT>  Can you please check it again. Cause the BigInteger extends fron Java Number where as Int extends from Kotlin Number class Thats why it resolves to any. May be I am wrong but still Its good to recheck

```
/**
 * You can edit, run, and share this code. 
 * <http://play.kotlinlang.org|play.kotlinlang.org> 
 *
 */

import java.math.BigInteger

fun main() {
    print(BigInteger("123") is kotlin.Number)
}
```
This is what that link sends me to.  <https://pl.kotl.in/32qL74dYR>
And it prints `true`.

weird… now it works! Yesterday I swear it displayed different code :slightly_smiling_face: Thanks