Disable deprecation warnings in the Scala REPL

Question

Is it possible to disable deprecation warnings in the Scala REPL?

E.g. when I type:

scala> List(1,2,3).toSet()

I get a deprecation warning:

<console>:12: warning: Adaptation of argument list by inserting () is deprecated: this is unlikely to be what you want.
        signature: GenSetLike.apply(elem: A): Boolean
  given arguments: <none>
 after adaptation: GenSetLike((): Unit)
       List(1,2,3).toSet()
                        ^

Is it somehow possible to disable those warnings?

PS: I know that this is not a good idea for development, just need it for a presentation.

This can help you may be https://github.com/scala/bug/issues/7934 — Raman Mishra, Jan 18 '19 at 14:36
That was just an example. I just want to deactivate the warnings. — Florian Baierl, Jan 18 '19 at 15:37
If you're doing a presentation, consider recording your terminal session with [asciinema](https://asciinema.org/) then editing the lines out — the recordings it generates are plain text and it's easy to delete any text you don't want displayed. — gutch, Jan 18 '19 at 22:34
The warning in this case is that you should should have entered just `List(1,2,3).toSet` (without the empty parentheses). In _Scala_, use of empty parentheses is a convention to denote parameterless functions that have side-effects. Meanwhile, parameterless functions with no parentheses (like most conversion operations) indicates that they do not have side effects. — Mike Allen, Jan 21 '19 at 00:25

score 2 · Accepted Answer · answered Jan 21 '19 at 00:18

Warnings can be disabled by adding -nowarn flag. Example:

$ scala -nowarn

Then your example will print:

scala> List(1,2,3).toSet()
res0: Boolean = false

scala>

However I don't recommend turning off those warnings (even for presentation). Please have a look at the result type of List(1,2,3).toSet(), it's Boolean not a Set[Int].

Disable deprecation warnings in the Scala REPL

1 Answers1