Is there an equivalent to SuppressWarnings in Scala? - scala

Question

I was wondering if scala had an equivalent to java's #SuppressWarnings that can be applied to a function or whatever to ignore any deprecation warnings[1] that function emits?
1: Relevant warning in my case is: method stop in class Thread is deprecated: see corresponding Javadoc for more information. I am aware of the problems with stop however there are still some cases where due to legacy code we have to use it.

Answer 1

No, and an enhancement request [1] for such a feature was closed as wontfix.
I agree it would be useful. I expect that the Scala core team aren't against the idea, but they have finite resources and many higher priorities.
update: this feature was eventually implemented in scala 2.13.2 release on 2020-04-22, see this answer
[1] https://issues.scala-lang.org/browse/SI-1781

Answer 2

EDIT: You should use #nowarn
There is a simple compiler plugin for this: silencer (a bit shameless plug)

Answer 3

Scala 2.13.2 provides #nowarn annotation developed on the basis of ghik's silencer, for example
import scala.annotation.nowarn
def t = { 0: #nowarn; 1 }
raises no warnings, whilst
def t = { 0; 1 }
gives
warning: a pure expression does nothing in statement position; multiline expressions might require enclosing parentheses
def t = { 0; 1 }
^

Answer 4

Here is how to suppress all warnings in sbt:
import sbt._
import Keys._
import KeyRanks.DTask
import xsbti.{Reporter, Problem, Position, Severity}
private lazy val compilerReporter = TaskKey[xsbti.Reporter](
"compilerReporter",
"Experimental hook to listen (or send) compilation failure messages.",
DTask
)
val ignoreWarnings = Seq(
compilerReporter in (Compile, compile) :=
new xsbti.Reporter {
private val buffer = collection.mutable.ArrayBuffer.empty[Problem]
def reset(): Unit = buffer.clear()
def hasErrors: Boolean = buffer.exists(_.severity == Severity.Error)
def hasWarnings: Boolean = buffer.exists(_.severity == Severity.Warn)
def printSummary(): Unit = {
print("\033c")
if (problems.nonEmpty) {
problems.foreach{ p =>
println("=====================================================")
println(p.position)
println(p.message)
println()
println()
}
}
}
def problems: Array[Problem] = buffer.toArray
def log(problem: Problem): Unit = {
if (problem.severity == Severity.Error) {
buffer.append(problem)
}
}
def log(pos: Position, msg: String, sev: Severity): Unit = {
log(new Problem {
def category: String = "foo"
def severity: Severity = sev
def message: String = msg
def position: Position = pos
})
}
def comment(pos: xsbti.Position, msg: String): Unit = ()
}
)