[SOLVED] getting Suspicious application of an implicit view when converting from Option(lang.Long) to Long

getting Suspicious application of an implicit view when converting from Option(lang.Long) to Long

after adding this flag to scalacoptions :

  "-Xlint:option-implicit"

I don't understand why am I getting this and how to resolve it

Error:(47, 34) Suspicious application of an implicit view (scala.Predef.Long2long) in the argument to Option.apply. val x: Long = Option[Long](timestamp()).getOrElse(1L)

The code looks like this

val x: Long = Option[Long](timestamp()).getOrElse(1L)

the function timestamp can be null or return java Long

Solution

I was able to replicate the message with the following code:

$ scala -Xlint:option-implicit
Welcome to Scala 2.13.0 (OpenJDK 64-Bit Server VM, Java 1.8.0_222).
Type in expressions for evaluation. Or try :help.

scala> def timestamp(): java.lang.Long = new java.lang.Long("10")

scala> val x: Long = Option[Long](timestamp()).getOrElse(1L)
warning: Suspicious application of an implicit view (scala.Predef.Long2long) in the argument to Option.apply.

Now, you can fix it the following way.

val x: Long = Option(Long.unbox(timestamp())).getOrElse(1L)

// Or, supposing opt is of type Option[java.lang.Long]
val x: Long = opt.fold(ifEmpty = 1L)(Long.unbox)