That was the initial intent behind Kotlin's Result<T> type; it was only allowed to be a return value from compiler-blessed functions (runCatching and friends) a

That was the initial intent behind Kotlin's Result<T> type; it was only allowed to be a return value from compiler-blessed functions (runCatching and friends) and was not allowed to be stored in a property. The problem became this additional function color; also, no language construct can prevent users from implementing "fun Result<T>.unwrap(): T" and crashing the program in the failure case. OK, you could also restrict functions that accept Result<T> (as a receiver or parameter), but now you force resolution of that type by the direct caller of the function returning Result<T>. So really this becomes a worse version of checked exceptions, which (thankfully) don't exist in Kotlin.