Scala example source code file (Warnings.scala)

This example Scala source code file (Warnings.scala) is included in my "Source Code Warehouse" project. The intent of this project is to help you more easily find Scala source code examples by using tags.

All credit for the original source code belongs to scala-lang.org; I'm just trying to make examples easier to find. (For my Scala work, see my Scala examples and tutorials.)

Scala tags/keywords

booleansetting, enable, fail, list, this, use, warn, xcheck-null, xlint, ywarn-unused-import

The Warnings.scala Scala example source code

/* NSC -- new Scala compiler
 * Copyright 2005-2013 LAMP/EPFL
 * @author  Paul Phillips
 */

package scala.tools
package nsc
package settings

import language.existentials

/** Settings influencing the printing of warnings.
 */
trait Warnings {
  self: MutableSettings =>

  // Warning semantics.
  val fatalWarnings = BooleanSetting("-Xfatal-warnings", "Fail the compilation if there are any warnings.")

  // These warnings are all so noisy as to be useless in their
  // present form, but have the potential to offer useful info.
  protected def allWarnings = lintWarnings ++ List(
    warnDeadCode,
    warnValueDiscard,
    warnNumericWiden
  )
  // These warnings should be pretty quiet unless you're doing
  // something inadvisable.
  protected def lintWarnings = List(
    warnInaccessible,
    warnNullaryOverride,
    warnNullaryUnit,
    warnAdaptedArgs,
    warnInferAny
    // warnUnused       SI-7712, SI-7707 warnUnused not quite ready for prime-time
    // warnUnusedImport currently considered too noisy for general use
  )

  private lazy val warnSelectNullable = BooleanSetting("-Xcheck-null", "This option is obsolete and does nothing.")

  // Individual warnings.
  val warnAdaptedArgs      = BooleanSetting   ("-Ywarn-adapted-args", "Warn if an argument list is modified to match the receiver.")
  val warnDeadCode         = BooleanSetting   ("-Ywarn-dead-code", "Warn when dead code is identified.")
  val warnValueDiscard     = BooleanSetting   ("-Ywarn-value-discard", "Warn when non-Unit expression results are unused.")
  val warnNumericWiden     = BooleanSetting   ("-Ywarn-numeric-widen", "Warn when numerics are widened.")
  val warnNullaryUnit      = BooleanSetting   ("-Ywarn-nullary-unit", "Warn when nullary methods return Unit.")
  val warnInaccessible     = BooleanSetting   ("-Ywarn-inaccessible", "Warn about inaccessible types in method signatures.")
  val warnNullaryOverride  = BooleanSetting   ("-Ywarn-nullary-override", "Warn when non-nullary overrides nullary, e.g. `def foo()` over `def foo`.")
  val warnInferAny         = BooleanSetting   ("-Ywarn-infer-any", "Warn when a type argument is inferred to be `Any`.")
  val warnUnused           = BooleanSetting   ("-Ywarn-unused", "Warn when local and private vals, vars, defs, and types are are unused")
  val warnUnusedImport     = BooleanSetting   ("-Ywarn-unused-import", "Warn when imports are unused")

   // Warning groups.
  val lint = BooleanSetting("-Xlint", "Enable recommended additional warnings.") enablingIfNotSetByUser lintWarnings

  // Backward compatibility.
  @deprecated("Use fatalWarnings", "2.11.0") def Xwarnfatal            = fatalWarnings      // used by sbt
  @deprecated("This option is being removed", "2.11.0") def Xchecknull = warnSelectNullable // used by ide
  @deprecated("Use warnDeadCode", "2.11.0") def Ywarndeadcode          = warnDeadCode       // used by ide
}