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

# announcements

[Toddobryan]

Can anybody think why this resolves to type Any? instead of Number?

fun String.toNumber(): Number? = toIntOrNull() ?: toLongOrNull() ?: toBigIntegerOrNull()

[Mike]

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

[Hullaballoonatic]

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.

[Hullaballoonatic]

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

[Toddobryan]

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

[vs.thaakur]

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

[vs.thaakur]

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

[Toddobryan]

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

[Matteo Mirk]

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

[vs.thaakur]

@Toddobryan 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

[Toddobryan]

/**
 * 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.

[Matteo Mirk]

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