Merge pull request #3792 from som-snytt/issue/8525

SI-8525 -Xlint:nowarn-missing-interpolator

10 files changed, 177 insertions, 59 deletions

diff --git a/src/compiler/scala/tools/nsc/plugins/Plugins.scala b/src/compiler/scala/tools/nsc/plugins/Plugins.scala
index 12f9aeba27..6e3d013e52 100644
--- a/src/compiler/scala/tools/nsc/plugins/Plugins.scala
+++ b/src/compiler/scala/tools/nsc/plugins/Plugins.scala
@@ -33,7 +33,7 @@ trait Plugins { global: Global =>
     }
     val maybes = Plugin.loadAllFrom(paths, dirs, settings.disable.value)
     val (goods, errors) = maybes partition (_.isSuccess)
-    // Explicit parameterization of recover to suppress -Xlint warning about inferred Any
+    // Explicit parameterization of recover to avoid -Xlint warning about inferred Any
     errors foreach (_.recover[Any] {
       // legacy behavior ignores altogether, so at least warn devs
       case e: MissingPluginException => if (global.isDeveloper) warning(e.getMessage)
diff --git a/src/compiler/scala/tools/nsc/settings/AbsScalaSettings.scala b/src/compiler/scala/tools/nsc/settings/AbsScalaSettings.scala
index 38a7525862..ef9695a594 100644
--- a/src/compiler/scala/tools/nsc/settings/AbsScalaSettings.scala
+++ b/src/compiler/scala/tools/nsc/settings/AbsScalaSettings.scala
@@ -29,7 +29,7 @@ trait AbsScalaSettings {
   def ChoiceSetting(name: String, helpArg: String, descr: String, choices: List[String], default: String): ChoiceSetting
   def IntSetting(name: String, descr: String, default: Int, range: Option[(Int, Int)], parser: String => Option[Int]): IntSetting
   def MultiStringSetting(name: String, helpArg: String, descr: String): MultiStringSetting
-  def MultiChoiceSetting(name: String, helpArg: String, descr: String, choices: List[String]): MultiChoiceSetting
+  def MultiChoiceSetting(name: String, helpArg: String, descr: String, choices: List[String], default: () => Unit): MultiChoiceSetting
   def OutputSetting(outputDirs: OutputDirs, default: String): OutputSetting
   def PathSetting(name: String, descr: String, default: String): PathSetting
   def PhasesSetting(name: String, descr: String, default: String): PhasesSetting
diff --git a/src/compiler/scala/tools/nsc/settings/MutableSettings.scala b/src/compiler/scala/tools/nsc/settings/MutableSettings.scala
index 54e444decf..dc49e8b822 100644
--- a/src/compiler/scala/tools/nsc/settings/MutableSettings.scala
+++ b/src/compiler/scala/tools/nsc/settings/MutableSettings.scala
@@ -211,11 +211,8 @@ class MutableSettings(val errorFn: String => Unit)
     add(new ChoiceSetting(name, helpArg, descr, choices, default))
   def IntSetting(name: String, descr: String, default: Int, range: Option[(Int, Int)], parser: String => Option[Int]) = add(new IntSetting(name, descr, default, range, parser))
   def MultiStringSetting(name: String, arg: String, descr: String) = add(new MultiStringSetting(name, arg, descr))
-  def MultiChoiceSetting(name: String, helpArg: String, descr: String, choices: List[String]): MultiChoiceSetting = {
-    val fullChoix = choices.mkString(": ", ",", ".")
-    val fullDescr = s"$descr$fullChoix"
-    add(new MultiChoiceSetting(name, helpArg, fullDescr, choices))
-  }
+  def MultiChoiceSetting(name: String, helpArg: String, descr: String, choices: List[String], default: () => Unit = () => ()) =
+    add(new MultiChoiceSetting(name, helpArg, descr, choices, default))
   def OutputSetting(outputDirs: OutputDirs, default: String) = add(new OutputSetting(outputDirs, default))
   def PhasesSetting(name: String, descr: String, default: String = "") = add(new PhasesSetting(name, descr, default))
   def StringSetting(name: String, arg: String, descr: String, default: String) = add(new StringSetting(name, arg, descr, default))
@@ -444,7 +441,7 @@ class MutableSettings(val errorFn: String => Unit)
       value = s.equalsIgnoreCase("true")
     }
     override def tryToSetColon(args: List[String]) = args match {
-      case Nil => tryToSet(Nil)
+      case Nil     => tryToSet(Nil)
       case List(x) =>
         if (x.equalsIgnoreCase("true")) {
           value = true
@@ -452,7 +449,8 @@ class MutableSettings(val errorFn: String => Unit)
         } else if (x.equalsIgnoreCase("false")) {
           value = false
           Some(Nil)
-        } else errorAndValue("'" + x + "' is not a valid choice for '" + name + "'", None)
+        } else errorAndValue(s"'$x' is not a valid choice for '$name'", None)
+      case _       => errorAndValue(s"'$name' accepts only one boolean value", None)
     }
   }
 
@@ -553,12 +551,43 @@ class MutableSettings(val errorFn: String => Unit)
       }
   }
 
+  /** A setting that receives any combination of enumerated values,
+   *  including "_" to mean all values.
+   *  In non-colonated mode, stops consuming args at the first
+   *  non-value, instead of at the next option, as for a multi-string.
+   */
   class MultiChoiceSetting private[nsc](
     name: String,
     arg: String,
     descr: String,
-    override val choices: List[String])
-  extends MultiStringSetting(name, arg, descr)
+    override val choices: List[String],
+    val default: () => Unit
+  ) extends MultiStringSetting(name, arg, s"$descr${ choices.mkString(": ", ",", ".") }") {
+
+    def badChoice(s: String, n: String) = errorFn(s"'$s' is not a valid choice for '$name'")
+    def choosing = choices.nonEmpty
+    def isChoice(s: String) = (s == "_") || (choices contains (s stripPrefix "-"))
+    def wildcards = choices // filter (!_.isSetByUser)
+
+    override protected def tts(args: List[String], halting: Boolean) = {
+      val total = collection.mutable.ListBuffer.empty[String] ++ value
+      def tryArg(arg: String) = arg match {
+        case "_" if choosing               => wildcards foreach (total += _)
+        case s if !choosing || isChoice(s) => total += s
+        case s                             => badChoice(s, name)
+      }
+      def stoppingAt(arg: String) = (arg startsWith "-") || (choosing && !isChoice(arg))
+      def loop(args: List[String]): List[String] = args match {
+        case arg :: _ if halting && stoppingAt(arg) => args
+        case arg :: rest                            => tryArg(arg) ; loop(rest)
+        case Nil                                    => Nil
+      }
+      val rest = loop(args)
+      if (rest.size == args.size) default()       // if no arg consumed, trigger default action
+      else value = total.toList                   // update once
+      Some(rest)
+    }
+  }
 
   /** A setting that accumulates all strings supplied to it,
    *  until it encounters one starting with a '-'.
@@ -570,24 +599,23 @@ class MutableSettings(val errorFn: String => Unit)
   extends Setting(name, descr) with Clearable {
     type T = List[String]
     protected var v: T = Nil
-    def appendToValue(str: String) { value ++= List(str) }
-    def badChoice(s: String, n: String) = errorFn(s"'$s' is not a valid choice for '$name'")
+    def appendToValue(str: String) = value ++= List(str)
 
-    def tryToSet(args: List[String]) = {
-      val (strings, rest) = args span (x => !x.startsWith("-"))
-      strings foreach {
-        case "_" if choices.nonEmpty => choices foreach appendToValue
-        case s if choices.isEmpty || (choices contains s) => appendToValue(s)
-        case s => badChoice(s, name)
+    // try to set. halting means halt at first non-arg
+    protected def tts(args: List[String], halting: Boolean) = {
+      def loop(args: List[String]): List[String] = args match {
+        case arg :: rest => if (halting && (arg startsWith "-")) args else { appendToValue(arg) ; loop(rest) }
+        case Nil         => Nil
       }
-      Some(rest)
+      Some(loop(args))
     }
-    override def tryToSetColon(args: List[String]) = tryToSet(args)
+    def tryToSet(args: List[String])                  = tts(args, halting = true)
+    override def tryToSetColon(args: List[String])    = tts(args, halting = false)
     override def tryToSetFromPropertyValue(s: String) = tryToSet(s.trim.split(',').toList) // used from ide
-    def clear(): Unit = (v = Nil)
-    def unparse: List[String] = value map (name + ":" + _)
 
-    def contains(s: String) = value contains s
+    def clear(): Unit         = (v = Nil)
+    def unparse: List[String] = value map (name + ":" + _)
+    def contains(s: String)   = value contains s
 
     withHelpSyntax(name + ":<" + arg + ">")
   }
@@ -606,10 +634,8 @@ class MutableSettings(val errorFn: String => Unit)
     protected var v: T = default
     def indexOfChoice: Int = choices indexOf value
 
-    private def usageErrorMessage = {
-      "Usage: %s:<%s>\n  where <%s> choices are %s (default: %s)\n".format(
-        name, helpArg, helpArg, choices mkString ", ", default)
-    }
+    private def usageErrorMessage = f"Usage: $name:<$helpArg>%n where <$helpArg> choices are ${choices mkString ", "} (default: $default)%n"
+
     def tryToSet(args: List[String]) = errorAndValue(usageErrorMessage, None)
 
     override def tryToSetColon(args: List[String]) = args match {
diff --git a/src/compiler/scala/tools/nsc/settings/Warnings.scala b/src/compiler/scala/tools/nsc/settings/Warnings.scala
index 1509ad13b8..3ff2369f86 100644
--- a/src/compiler/scala/tools/nsc/settings/Warnings.scala
+++ b/src/compiler/scala/tools/nsc/settings/Warnings.scala
@@ -31,27 +31,120 @@ trait Warnings {
     warnNullaryOverride,
     warnNullaryUnit,
     warnAdaptedArgs,
-    warnInferAny
+    warnInferAny,
     // warnUnused       SI-7712, SI-7707 warnUnused not quite ready for prime-time
     // warnUnusedImport currently considered too noisy for general use
+    // warnValueOverrides
+    warnMissingInterpolator,
+    warnDocDetached,
+    warnPrivateShadow,
+    warnPolyImplicitOverload,
+    warnOptionImplicit,
+    warnDelayedInit,
+    warnByNameRightAssociative,
+    warnPackageObjectClasses,
+    warnUnsoundMatch
   )
 
   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
+  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 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")
+
+  // Lint warnings that are not -Y, created with new instead of autoregistering factory method
+  private def lintflag(name: String, text: String) = new BooleanSetting(name, text)
+
+  val warnAdaptedArgs          = lintflag("adapted-args",
+                                 "Warn if an argument list is modified to match the receiver.")
+  val warnNullaryUnit          = lintflag("nullary-unit",
+                                 "Warn when nullary methods return Unit.")
+  val warnInaccessible         = lintflag("inaccessible",
+                                "Warn about inaccessible types in method signatures.")
+  val warnNullaryOverride      = lintflag("nullary-override",
+                                "Warn when non-nullary `def f()' overrides nullary `def f'.")
+  val warnInferAny             = lintflag("infer-any",
+                                "Warn when a type argument is inferred to be `Any`.")
+  val warnMissingInterpolator  = lintflag("missing-interpolator",
+                                "A string literal appears to be missing an interpolator id.")
+  val warnDocDetached          = lintflag("doc-detached",
+                                "A ScalaDoc comment appears to be detached from its element.")
+  val warnPrivateShadow        = lintflag("private-shadow",
+                                "A private field (or class parameter) shadows a superclass field.")
+  val warnPolyImplicitOverload = lintflag("poly-implicit-overload",
+                                "Parameterized overloaded implicit methods are not visible as view bounds")
+  val warnOptionImplicit       = lintflag("option-implicit",
+                                "Option.apply used implicit view.")
+  val warnDelayedInit          = lintflag("delayedinit-select",
+                                "Selecting member of DelayedInit")
+  val warnByNameRightAssociative = lintflag("by-name-right-associative",
+                                "By-name parameter of right associative operator")
+  val warnPackageObjectClasses = lintflag("package-object-classes",
+                                "Class or object defined in package object")
+  val warnUnsoundMatch         = lintflag("unsound-match",
+                                "Pattern match may not be typesafe")
+
+  // Lint warnings that are not enabled yet
+  val warnValueOverrides = lintflag("value-overrides", "Generated value class method overrides an implementation")
+
+  // Warning groups.
+  val lint                 = {
+    // Boolean setting for testing if lint is on; not "added" to option processing
+    val xlint = lintflag("-Xlint", "Enable recommended additional warnings.")
+    val yprefix = "-Ywarn-"
+    def lintables = (lintWarnings map (_.name stripPrefix yprefix)).sorted
+    def isAnon(b: BooleanSetting) = !(b.name startsWith "-")
+    def setPolitely(b: BooleanSetting, v: Boolean) = if (!b.isSetByUser) b.value = v
+    def set(w: String, v: Boolean) = lintWarnings find (s => (s.name stripPrefix yprefix) == w) foreach (b => setPolitely(b, v))
+    val Neg = "-"
+    def propagate(ss: List[String]): Unit = ss match {
+      case w :: rest => if (w startsWith Neg) set(w stripPrefix Neg, false) else set(w, true) ; propagate(rest)
+      case Nil       => ()
+    }
+    // enable lint and the group, honoring previous -Y settings
+    def enableAll(): Unit = {
+      xlint.value = true
+      for (s <- lintWarnings) setPolitely(s, true)
+    }
+    // The command option
+    MultiChoiceSetting("-Xlint", "warning", "Enable recommended additional warnings", choices = lintables, default = enableAll) withPostSetHook { x =>
+      propagate(x.value)      // enabling the selections (on each append to value)
+      xlint.value = true      // only enables lint, not the group
+      for (b <- lintWarnings if isAnon(b) && !b.isSetByUser) b.value = true   // init anonymous settings (but not if disabled)
+    }
+    xlint
+  }
+
+  // Lint warnings that are currently -Y, but deprecated in that usage
+  // Alas, the -Yarg must have a doppelgaenger that is not deprecated
+  @deprecated("Use the Xlint flag", since="2.11.2")
+  val YwarnAdaptedArgs      = BooleanSetting("-Ywarn-adapted-args",
+                             "Warn if an argument list is modified to match the receiver.") withDeprecationMessage
+                             "Enable -Xlint:adapted-args" enabling List(warnAdaptedArgs)
+  @deprecated("Use the Xlint flag", since="2.11.2")
+  val YwarnNullaryUnit      = BooleanSetting("-Ywarn-nullary-unit",
+                             "Warn when nullary methods return Unit.") withDeprecationMessage
+                             "Enable -Xlint:nullary-unit" enabling List(warnNullaryUnit)
+  @deprecated("Use the Xlint flag", since="2.11.2")
+  val YwarnInaccessible     = BooleanSetting("-Ywarn-inaccessible",
+                             "Warn about inaccessible types in method signatures.") withDeprecationMessage
+                             "Enable -Xlint:inaccessible" enabling List(warnInaccessible)
+  @deprecated("Use the Xlint flag", since="2.11.2")
+  val YwarnNullaryOverride  = BooleanSetting("-Ywarn-nullary-override",
+                             "Warn when non-nullary `def f()' overrides nullary `def f'.") withDeprecationMessage
+                             "Enable -Xlint:nullary-override" enabling List(warnNullaryOverride)
+  @deprecated("Use the Xlint flag", since="2.11.2")
+  val YwarnInferAny         = BooleanSetting("-Ywarn-infer-any",
+                             "Warn when a type argument is inferred to be `Any`.") withDeprecationMessage
+                             "Enable -Xlint:infer-any" enabling List(warnInferAny)
 
   // Backward compatibility.
   @deprecated("Use fatalWarnings", "2.11.0") def Xwarnfatal            = fatalWarnings      // used by sbt
diff --git a/src/compiler/scala/tools/nsc/transform/patmat/MatchAnalysis.scala b/src/compiler/scala/tools/nsc/transform/patmat/MatchAnalysis.scala
index 6f81cbe152..b2dc6e4e52 100644
--- a/src/compiler/scala/tools/nsc/transform/patmat/MatchAnalysis.scala
+++ b/src/compiler/scala/tools/nsc/transform/patmat/MatchAnalysis.scala
@@ -50,7 +50,7 @@ trait TreeAndTypeAnalysis extends Debugging {
           // but the annotation didn't bubble up...
           // This is a pretty poor approximation.
           def unsoundAssumptionUsed = binder.name != nme.WILDCARD && !(pt <:< pat.tpe)
-          if (settings.lint && unsoundAssumptionUsed)
+          if (settings.warnUnsoundMatch && unsoundAssumptionUsed)
             reporter.warning(pat.pos,
               sm"""The value matched by $pat is bound to ${binder.name}, which may be used under the
                   |unsound assumption that it has type ${pat.tpe}, whereas we can only safely
diff --git a/src/compiler/scala/tools/nsc/typechecker/Namers.scala b/src/compiler/scala/tools/nsc/typechecker/Namers.scala
index 1328119aac..7bbd81118a 100644
--- a/src/compiler/scala/tools/nsc/typechecker/Namers.scala
+++ b/src/compiler/scala/tools/nsc/typechecker/Namers.scala
@@ -717,7 +717,7 @@ trait Namers extends MethodSynthesis {
         m.updateAttachment(new ConstructorDefaultsAttachment(tree, null))
       }
       val owner = tree.symbol.owner
-      if (settings.lint && owner.isPackageObjectClass && !mods.isImplicit) {
+      if (settings.warnPackageObjectClasses && owner.isPackageObjectClass && !mods.isImplicit) {
         reporter.warning(tree.pos,
           "it is not recommended to define classes/objects inside of package objects.\n" +
           "If possible, define " + tree.symbol + " in " + owner.skipPackageObject + " instead."
diff --git a/src/compiler/scala/tools/nsc/typechecker/RefChecks.scala b/src/compiler/scala/tools/nsc/typechecker/RefChecks.scala
index 1b3da26bf2..47465875e9 100644
--- a/src/compiler/scala/tools/nsc/typechecker/RefChecks.scala
+++ b/src/compiler/scala/tools/nsc/typechecker/RefChecks.scala
@@ -167,7 +167,7 @@ abstract class RefChecks extends InfoTransform with scala.reflect.internal.trans
       }
 
       // This has become noisy with implicit classes.
-      if (settings.lint && settings.developer) {
+      if (settings.warnPolyImplicitOverload && settings.developer) {
         clazz.info.decls filter (x => x.isImplicit && x.typeParams.nonEmpty) foreach { sym =>
           // implicit classes leave both a module symbol and a method symbol as residue
           val alts = clazz.info.decl(sym.name).alternatives filterNot (_.isModule)
@@ -954,7 +954,7 @@ abstract class RefChecks extends InfoTransform with scala.reflect.internal.trans
       def apply(tp: Type) = mapOver(tp).normalize
     }
 
-    def checkImplicitViewOptionApply(pos: Position, fn: Tree, args: List[Tree]): Unit = if (settings.lint) (fn, args) match {
+    def checkImplicitViewOptionApply(pos: Position, fn: Tree, args: List[Tree]): Unit = if (settings.warnOptionImplicit) (fn, args) match {
       case (tap@TypeApply(fun, targs), List(view: ApplyImplicitView)) if fun.symbol == currentRun.runDefinitions.Option_apply =>
         reporter.warning(pos, s"Suspicious application of an implicit view (${view.fun}) in the argument to Option.apply.") // SI-6567
       case _ =>
@@ -1320,7 +1320,7 @@ abstract class RefChecks extends InfoTransform with scala.reflect.internal.trans
         && !qual.tpe.isInstanceOf[ThisType]
         && sym.accessedOrSelf.isVal
       )
-      if (settings.lint.value && isLikelyUninitialized)
+      if (settings.warnDelayedInit && isLikelyUninitialized)
         reporter.warning(pos, s"Selecting ${sym} from ${sym.owner}, which extends scala.DelayedInit, is likely to yield an uninitialized value")
     }
 
@@ -1387,7 +1387,7 @@ abstract class RefChecks extends InfoTransform with scala.reflect.internal.trans
     private def checkByNameRightAssociativeDef(tree: DefDef) {
       tree match {
         case DefDef(_, name, _, params :: _, _, _) =>
-          if (settings.lint && !treeInfo.isLeftAssoc(name.decodedName) && params.exists(p => isByName(p.symbol)))
+          if (settings.warnByNameRightAssociative && !treeInfo.isLeftAssoc(name.decodedName) && params.exists(p => isByName(p.symbol)))
             reporter.warning(tree.pos,
               "by-name parameters will be evaluated eagerly when called as a right-associative infix operator. For more details, see SI-1980.")
         case _ =>
diff --git a/src/compiler/scala/tools/nsc/typechecker/SuperAccessors.scala b/src/compiler/scala/tools/nsc/typechecker/SuperAccessors.scala
index d3a41b9570..38b00a015b 100644
--- a/src/compiler/scala/tools/nsc/typechecker/SuperAccessors.scala
+++ b/src/compiler/scala/tools/nsc/typechecker/SuperAccessors.scala
@@ -247,7 +247,7 @@ abstract class SuperAccessors extends transform.Transform with transform.TypingT
               // also exists in a superclass, because they may be surprised
               // to find out that a constructor parameter will shadow a
               // field. See SI-4762.
-              if (settings.lint) {
+              if (settings.warnPrivateShadow) {
                 if (sym.isPrivateLocal && sym.paramss.isEmpty) {
                   qual.symbol.ancestors foreach { parent =>
                     parent.info.decls filterNot (x => x.isPrivate || x.isLocalToThis) foreach { m2 =>
diff --git a/src/compiler/scala/tools/nsc/typechecker/SyntheticMethods.scala b/src/compiler/scala/tools/nsc/typechecker/SyntheticMethods.scala
index 9516f94135..d0237fb468 100644
--- a/src/compiler/scala/tools/nsc/typechecker/SyntheticMethods.scala
+++ b/src/compiler/scala/tools/nsc/typechecker/SyntheticMethods.scala
@@ -339,12 +339,11 @@ trait SyntheticMethods extends ast.TreeDSL {
           !hasOverridingImplementation(m) || {
             clazz.isDerivedValueClass && (m == Any_hashCode || m == Any_equals) && {
               // Without a means to suppress this warning, I've thought better of it.
-              //
-              // if (settings.lint) {
-              //   (clazz.info nonPrivateMember m.name) filter (m => (m.owner != AnyClass) && (m.owner != clazz) && !m.isDeferred) andAlso { m =>
-              //     currentUnit.warning(clazz.pos, s"Implementation of ${m.name} inherited from ${m.owner} overridden in $clazz to enforce value class semantics")
-              //   }
-              // }
+              if (settings.warnValueOverrides) {
+                 (clazz.info nonPrivateMember m.name) filter (m => (m.owner != AnyClass) && (m.owner != clazz) && !m.isDeferred) andAlso { m =>
+                   currentUnit.warning(clazz.pos, s"Implementation of ${m.name} inherited from ${m.owner} overridden in $clazz to enforce value class semantics")
+                 }
+               }
               true
             }
           }
diff --git a/src/compiler/scala/tools/nsc/typechecker/Typers.scala b/src/compiler/scala/tools/nsc/typechecker/Typers.scala
index 65f11a360e..70f44c4fc6 100644
--- a/src/compiler/scala/tools/nsc/typechecker/Typers.scala
+++ b/src/compiler/scala/tools/nsc/typechecker/Typers.scala
@@ -5099,7 +5099,7 @@ trait Typers extends Adaptations with Tags with TypersTracking with PatternTyper
         def isPlausible(m: Symbol) = m.alternatives exists (m => requiresNoArgs(m.info))
 
         def maybeWarn(s: String): Unit = {
-          def warn(message: String)         = context.warning(lit.pos, s"$message Did you forget the interpolator?")
+          def warn(message: String)         = context.warning(lit.pos, s"possible missing interpolator: $message")
           def suspiciousSym(name: TermName) = context.lookupSymbol(name, _ => true).symbol
           def suspiciousExpr                = InterpolatorCodeRegex findFirstIn s
           def suspiciousIdents              = InterpolatorIdentRegex findAllIn s map (s => suspiciousSym(s drop 1))
@@ -5107,9 +5107,9 @@ trait Typers extends Adaptations with Tags with TypersTracking with PatternTyper
           // heuristics - no warning on e.g. a string with only "$asInstanceOf"
           if (s contains ' ') (
             if (suspiciousExpr.nonEmpty)
-              warn("That looks like an interpolated expression!") // "${...}"
+              warn("detected an interpolated expression") // "${...}"
             else
-              suspiciousIdents find isPlausible foreach (sym => warn(s"`$$${sym.name}` looks like an interpolated identifier!")) // "$id"
+              suspiciousIdents find isPlausible foreach (sym => warn(s"detected interpolated identifier `$$${sym.name}`")) // "$id"
           )
         }
         lit match {
@@ -5119,7 +5119,7 @@ trait Typers extends Adaptations with Tags with TypersTracking with PatternTyper
       }
 
       def typedLiteral(tree: Literal) = {
-        if (settings.lint) warnMissingInterpolator(tree)
+        if (settings.warnMissingInterpolator) warnMissingInterpolator(tree)
 
         tree setType (if (tree.value.tag == UnitTag) UnitTpe else ConstantType(tree.value))
       }