CODEWITHSUNDEEP
scala
Nitin
Nitin

Reputation: 169

Why does Option(null).map result in an error?

Let's say I have defined a function as:

f:(Int)=>String

Why does the following result in error?

Option(null).map(f)

While the following just works fine?

None.map(f)

PS: Option(null) evaluates to None

Edit: Following is the error I see on scala console 

scala> Option(null).map(f)
<console>:14: error: type mismatch;
found   : Int => String
required: Null => ?
   Option(null).map(f)

Upvotes: 1

Views: 119

Answers (1)

Jasper-M
Jasper-M

Reputation: 15086

The expression Option(null) has type Option[Null], while None is an instance of Option[Nothing]. Null is not a subtype of Int, but Nothing is.

Option(null) evaluates to None but that is not known at compile time. It doesn't make any sense to literally write Option(null) anyway. That construct is only useful when you're not sure whether the argument is null or not.

Upvotes: 6

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