BigInteger.kt

BigInteger.kt

expect class BigInteger(value: String) : Number, Comparable<BigInteger> {
}

// ...

typealias JvmBigInteger = java.math.BigInteger

actual class BigInteger actual constructor(value: String) : JvmBigInteger(value), Comparable<BigInteger> {    // <<< Error below
   // ..
}

// ..

// Actual class 'BigInteger' has no corresponding expected declaration The following declaration is incompatible because some supertypes are missing in the actual declaration:
// `public final expect class BigInteger : Number, Comparable<BigInteger>` defined in kmulti.bignumber in file BigInteger.kt

// Also

// Type parameter T of 'Comparable' has inconsistent values: java.math.BigDecimal!, kmulti.bignumber.BigDecimal