Fate of null in Scala

Syntax
1

Have we considered that compiler should give a warning in these scenarios?

var ctx:Context = null

case class Employee(val age:Int, val reports:List[Employee] = null)

def readFile(path:String):String = {
  if(!File.exists(path)) {
    return null
  }
}

Basically whenever we are setting or returning null. The only risk I see is that some projects might have setting to fail if warning present, but am sure it would be helpful to them.

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2

Maybe wartremover has something for this?

(And/or perhaps there are scalafix rules out there?)

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3

There’s Explicit Nulls in Scala 3. It’s still experimental, and unless I’ve been doing something wrong, it doesn’t seem to consistently honor the corresponding annotations in Java libs, so I had to #nn the hell out of Java interop in my experiments.

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