Potentially annoying lints for -Wperformance

src/compiler/scala/tools/nsc/settings/Warnings.scala

@@ -98,7 +98,7 @@ trait Warnings {
          |to prevent the shell from expanding patterns.""".stripMargin),
     prepend = true)
 
-  // Non-lint warnings. -- TODO turn into MultiChoiceEnumeration
+  // Non-lint warnings.
   val warnMacros           = ChoiceSetting(
     name    = "-Wmacros",
     helpArg = "mode",
@@ -117,6 +117,20 @@ trait Warnings {
   val warnNumericWiden     = BooleanSetting("-Wnumeric-widen", "Warn when numerics are widened.") withAbbreviation "-Ywarn-numeric-widen"
   val warnOctalLiteral     = BooleanSetting("-Woctal-literal", "Warn on obsolete octal syntax.") withAbbreviation "-Ywarn-octal-literal"
 
+  object PerformanceWarnings extends MultiChoiceEnumeration {
+    val Captured       = Choice("captured",        "Modification of var in closure causes boxing.")
+    val NonlocalReturn = Choice("nonlocal-return", "A return statement used an exception for flow control.")
+  }
+  val warnPerformance = MultiChoiceSetting(
+    name    = "-Wperformance",
+    helpArg = "warning",
+    descr   = "Enable or disable specific lints for performance",
+    domain  = PerformanceWarnings,
+    default = Some(List("_"))
+  )
+  def warnCaptured       = warnPerformance.contains(PerformanceWarnings.Captured)
+  def warnNonlocalReturn = warnPerformance.contains(PerformanceWarnings.NonlocalReturn)
+
   object UnusedWarnings extends MultiChoiceEnumeration {
     val Imports   = Choice("imports",   "Warn if an import selector is not referenced.")
     val PatVars   = Choice("patvars",   "Warn if a variable bound in a pattern is unused.")
@@ -182,7 +196,6 @@ trait Warnings {
     val StrictUnsealedPatMat   = LintWarning("strict-unsealed-patmat",    "Pattern match on an unsealed class without a catch-all.")
     val Constant               = LintWarning("constant",                  "Evaluation of a constant arithmetic expression resulted in an error.")
     val Unused                 = LintWarning("unused",                    "Enable -Wunused:imports,privates,locals,implicits,nowarn.")
-    val NonlocalReturn         = LintWarning("nonlocal-return",           "A return statement used an exception for flow control.")
     val ImplicitNotFound       = LintWarning("implicit-not-found",        "Check @implicitNotFound and @implicitAmbiguous messages.")
     val Serial                 = LintWarning("serial",                    "@SerialVersionUID on traits and non-serializable classes.")
     val ValPattern             = LintWarning("valpattern",                "Enable pattern checks in val definitions.")
@@ -194,7 +207,6 @@ trait Warnings {
     val UnitSpecialization     = LintWarning("unit-special",              "Warn for specialization of Unit in parameter position.")
     val MultiargInfix          = LintWarning("multiarg-infix",            "Infix operator was defined or used with multiarg operand.")
     val ImplicitRecursion      = LintWarning("implicit-recursion",        "Implicit resolves to an enclosing definition.")
-    val Captured               = LintWarning("captured",                  "Modification of var in closure causes boxing.")
 
     def allLintWarnings = values.toSeq.asInstanceOf[Seq[LintWarning]]
   }
@@ -215,9 +227,7 @@ trait Warnings {
   def warnStrictUnsealedPatMat   = lint contains StrictUnsealedPatMat
   def warnStarsAlign             = lint contains StarsAlign
   def warnConstant               = lint contains Constant
-  def warnCaptured               = lint contains Captured
   def lintUnused                 = lint contains Unused
-  def warnNonlocalReturn         = lint contains NonlocalReturn
   def lintImplicitNotFound       = lint contains ImplicitNotFound
   def warnSerialization          = lint contains Serial
   def lintValPatterns            = lint contains ValPattern

test/files/neg/xlint-captured.check

@@ -1,6 +1,9 @@
+xlint-captured.scala:10: warning: return statement uses an exception to pass control to the caller of the enclosing named method f
+  def f(): Unit = List(42).foreach(i => if (i > 27) return)
+                                                    ^
 xlint-captured.scala:5: warning: Modification of variable c within a closure causes it to be boxed.
     var c = a // nok
         ^
 error: No warnings can be incurred under -Werror.
-1 warning
+2 warnings
 1 error

test/files/neg/xlint-captured.scala

@@ -1,9 +1,11 @@
-// scalac: -Werror -Xlint:captured
+// scalac: -Werror -Wperformance
 object Test {
   var a, b = 0 // ok
   def mkStrangeCounter(): Int => Int = {
     var c = a // nok
     object _d { var d = b }; import _d._ // ok
     e => { c += a; d += b; a *= b; b -= c; c ^ d }
   }
+
+  def f(): Unit = List(42).foreach(i => if (i > 27) return)
 }