Removed a bunch of -Y warning options.

back in the form of a compiler plugin. Also promoted -Yfatal-warnings to
-Xfatal-warnings: this is key to writing tests which involve warnings
and should be at least semi-supported. Closes #3300, no review.

10 files changed, 12 insertions, 126 deletions

diff --git a/src/compiler/scala/tools/nsc/Global.scala b/src/compiler/scala/tools/nsc/Global.scala
index 16bff5d399..b43908c4f9 100644
--- a/src/compiler/scala/tools/nsc/Global.scala
+++ b/src/compiler/scala/tools/nsc/Global.scala
@@ -137,7 +137,7 @@ class Global(var settings: Settings, var reporter: Reporter) extends SymbolTable
 
   def error(msg: String) = reporter.error(NoPosition, msg)
   def warning(msg: String) =
-    if (settings.Ywarnfatal.value) reporter.error(NoPosition, msg)
+    if (settings.Xwarnfatal.value) reporter.error(NoPosition, msg)
     else reporter.warning(NoPosition, msg)
   def inform(msg: String) = reporter.info(NoPosition, msg, true)
   def inform[T](msg: String, value: T): T = { inform(msg+value); value }
diff --git a/src/compiler/scala/tools/nsc/reporters/AbstractReporter.scala b/src/compiler/scala/tools/nsc/reporters/AbstractReporter.scala
index ce10f560e9..e35843fc9c 100644
--- a/src/compiler/scala/tools/nsc/reporters/AbstractReporter.scala
+++ b/src/compiler/scala/tools/nsc/reporters/AbstractReporter.scala
@@ -29,7 +29,7 @@ abstract class AbstractReporter extends Reporter {
 
   protected def info0(pos: Position, msg: String, _severity: Severity, force: Boolean) {
     val severity =
-      if (settings.Ywarnfatal.value && _severity == WARNING) ERROR
+      if (settings.Xwarnfatal.value && _severity == WARNING) ERROR
       else _severity
 
     severity match {
diff --git a/src/compiler/scala/tools/nsc/settings/ScalaSettings.scala b/src/compiler/scala/tools/nsc/settings/ScalaSettings.scala
index 1b6b8297ef..54f4146f31 100644
--- a/src/compiler/scala/tools/nsc/settings/ScalaSettings.scala
+++ b/src/compiler/scala/tools/nsc/settings/ScalaSettings.scala
@@ -27,7 +27,6 @@ trait ScalaSettings extends AbsScalaSettings with StandardScalaSettings {
    *  Temporary Settings
    */
   val suppressVTWarn = BooleanSetting    ("-Ysuppress-vt-typer-warnings", "Suppress warnings from the typer when testing the virtual class encoding, NOT FOR FINAL!")
-  val javaignorecp   = BooleanSetting    ("-javaignorecp", "Does nothing - is being removed.")  // !!! marked for death, but need new starr.
 
   /**
    *  Standard settings
@@ -80,6 +79,9 @@ trait ScalaSettings extends AbsScalaSettings with StandardScalaSettings {
   val Xshowobj      = StringSetting     ("-Xshow-object", "object", "Show object info", "")
   val showPhases    = BooleanSetting    ("-Xshow-phases", "Print a synopsis of compiler phases")
   val sourceReader  = StringSetting     ("-Xsource-reader", "classname", "Specify a custom method for reading source files", "scala.tools.nsc.io.SourceReader")
+  val Xwarnfatal    = BooleanSetting    ("-Xfatal-warnings", "Fail the compilation if there are any warnings.")
+  val Xwarninit     = BooleanSetting    ("-Xwarninit", "Warn about possible changes in initialization semantics")
+  val Xchecknull    = BooleanSetting    ("-Xcheck-null", "Emit warning on selection of nullable reference")
 
   /** Compatibility stubs for options whose value name did
    *  not previously match the option name.
@@ -134,20 +136,11 @@ trait ScalaSettings extends AbsScalaSettings with StandardScalaSettings {
   val Ypmatdebug    = BooleanSetting    ("-Ypmat-debug", "Trace all pattern matcher activity.")
   val Yrepldebug    = BooleanSetting    ("-Yrepl-debug", "Trace all repl activity.")
   val Ypmatnaive    = BooleanSetting    ("-Ypmat-naive", "Desugar matches as naively as possible..")
-  val Ytailrec      = BooleanSetting    ("-Ytailrecommend", "Alert methods which would be tail-recursive if private or final.")
   val Yjenkins      = BooleanSetting    ("-Yjenkins-hashCodes", "Use jenkins hash algorithm for case class generated hashCodes.")
 
   // Warnings
-  val Ywarnfatal    = BooleanSetting    ("-Yfatal-warnings", "Fail the compilation if there are any warnings.")
-  val Xwarninit     = BooleanSetting    ("-Xwarninit", "Warn about possible changes in initialization semantics")
-  val Xchecknull    = BooleanSetting    ("-Xcheck-null", "Emit warning on selection of nullable reference")
-  val Xwarndeadcode = BooleanSetting    ("-Ywarn-dead-code", "Emit warnings for dead code")
-  val YwarnShadow   = BooleanSetting    ("-Ywarn-shadowing", "Emit warnings about possible variable shadowing.")
-  val YwarnCatches  = BooleanSetting    ("-Ywarn-catches", "Emit warnings about catch blocks which catch everything.")
-  val Xwarnings     = BooleanSetting    ("-Xstrict-warnings", "Emit warnings about lots of things.") .
-                          withPostSetHook(_ =>
-                            List(YwarnShadow, YwarnCatches, Xwarndeadcode, Xwarninit) foreach (_.value = true)
-                          )
+  val Ywarndeadcode = BooleanSetting    ("-Ywarn-dead-code", "Emit warnings for dead code")
+
   /**
    * "fsc-specific" settings.
    */
diff --git a/src/compiler/scala/tools/nsc/transform/TailCalls.scala b/src/compiler/scala/tools/nsc/transform/TailCalls.scala
index adeab550ee..effc75486d 100644
--- a/src/compiler/scala/tools/nsc/transform/TailCalls.scala
+++ b/src/compiler/scala/tools/nsc/transform/TailCalls.scala
@@ -163,15 +163,8 @@ abstract class TailCalls extends Transform
           newCtx.tailPos = true
 
           val isEligible = newCtx.currentMethod.isEffectivelyFinal || (newCtx.currentMethod.enclClass hasFlag Flags.MODULE)
-          // If -Ytailrecommend is given, we speculatively try transforming ineligible methods and
-          // report where we would have been successful.
-          val recommend = settings.Ytailrec.value
-          val savedFlags: Option[Long] = if (recommend) Some(newCtx.currentMethod.flags) else None
-
-          if (isEligible || recommend) {
-            if (recommend)
-              newCtx.currentMethod.flags |= Flags.FINAL
 
+          if (isEligible) {
             newCtx.tparams = Nil
             log("  Considering " + name + " for tailcalls")
             tree.symbol.tpe match {
@@ -185,7 +178,6 @@ abstract class TailCalls extends Transform
 
           val t1 = treeCopy.DefDef(tree, mods, name, tparams, vparams, tpt, {
             val transformed = transform(rhs, newCtx)
-            savedFlags foreach (newCtx.currentMethod.flags = _)
 
             transformed match {
               case newRHS if isEligible && newCtx.accessed =>
@@ -200,12 +192,6 @@ abstract class TailCalls extends Transform
                   List(ValDef(newThis, This(currentClass))),
                   LabelDef(newCtx.label, newThis :: (vparams.flatten map (_.symbol)), newRHS)
                 )))
-              case _ if recommend =>
-                if (newCtx.accessed)
-                  unit.warning(dd.pos, "method is tailrecommended")
-                // transform with the original flags restored
-                transform(rhs, newCtx)
-
               case rhs => rhs
             }
           })
diff --git a/src/compiler/scala/tools/nsc/transform/UnCurry.scala b/src/compiler/scala/tools/nsc/transform/UnCurry.scala
index e339560837..bad98193b0 100644
--- a/src/compiler/scala/tools/nsc/transform/UnCurry.scala
+++ b/src/compiler/scala/tools/nsc/transform/UnCurry.scala
@@ -659,11 +659,6 @@ abstract class UnCurry extends InfoTransform with TypingTransformers {
           }
           treeCopy.DefDef(tree, mods, name, tparams, List(vparamss.flatten), tpt, rhs1)
         case Try(body, catches, finalizer) =>
-          // If warnings are enabled, alert about promiscuously catching cases.
-          if (settings.YwarnCatches.value)
-            for (cd <- catches find treeInfo.catchesThrowable)
-              unit.warning(cd.pos, "catch clause swallows everything: not advised.")
-
           if (catches forall treeInfo.isCatchCase) tree
           else {
             val exname = unit.fresh.newName(tree.pos, "ex$")
diff --git a/src/compiler/scala/tools/nsc/typechecker/Infer.scala b/src/compiler/scala/tools/nsc/typechecker/Infer.scala
index c8d3308077..4557f7bde1 100644
--- a/src/compiler/scala/tools/nsc/typechecker/Infer.scala
+++ b/src/compiler/scala/tools/nsc/typechecker/Infer.scala
@@ -1591,7 +1591,7 @@ trait Infer {
     }
 
     def checkDead(tree: Tree): Tree = {
-      if (settings.Xwarndeadcode.value && tree.tpe != null && tree.tpe.typeSymbol == NothingClass)
+      if (settings.Ywarndeadcode.value && tree.tpe != null && tree.tpe.typeSymbol == NothingClass)
         context.warning (tree.pos, "dead code following this construct")
       tree
     }
diff --git a/src/compiler/scala/tools/nsc/typechecker/Typers.scala b/src/compiler/scala/tools/nsc/typechecker/Typers.scala
index 3fe937f241..0274dc8871 100644
--- a/src/compiler/scala/tools/nsc/typechecker/Typers.scala
+++ b/src/compiler/scala/tools/nsc/typechecker/Typers.scala
@@ -1676,77 +1676,6 @@ trait Typers { self: Analyzer =>
         }
       }
 
-    /** does given name name an identifier visible at this point?
-     *
-     *  @param name the given name
-     *  @return     <code>true</code> if an identifier with the given name is visible.
-     */
-    def namesSomeIdent(name: Name): Boolean = namesWhatIdent(name).isDefined
-
-    /** If this name returns a visible identifier, return its symbol.
-     *
-     *  @param name the given name
-     *  @return     <code>Some(sym)</code> if an ident is visible, None otherwise.
-     */
-    def namesWhatIdent(name: Name): Option[Symbol] = {
-      var cx = context
-      while (cx != NoContext) {
-        val pre = cx.enclClass.prefix
-        val defEntry = cx.scope.lookupEntry(name)
-        if ((defEntry ne null) && reallyExists(defEntry.sym))
-          return Some(defEntry.sym)
-
-        cx = cx.enclClass
-        (pre member name filter (sym => reallyExists(sym) && context.isAccessible(sym, pre, false))) match {
-          case NoSymbol   => cx = cx.outer
-          case other      => return Some(other)
-        }
-      }
-      context.imports map (_ importedSymbol name) find (_ != NoSymbol)
-    }
-
-    /** Does this tree declare a val or def with the same name as one in scope?
-     *  This only catches identifiers in the same file, so more work is needed.
-     *
-     *  @param    tree  the given tree
-     *  @param    filt  filter for any conflicting symbols found -- false means ignore
-     */
-    def checkShadowings(tree: Tree, filt: (Symbol) => Boolean = _ => true) {
-      def sameFile(other: Symbol) =
-        (tree.symbol != null) && tree.symbol.sourceFile == other.sourceFile
-      def inFile(other: Symbol) =
-        if (sameFile(other)) ""
-        else if (other.sourceFile != null) "in %s ".format(other.sourceFile)
-        else ""
-
-      def positionStr(other: Symbol) = other.pos match {
-        case NoPosition => inFile(other) match { case "" => "(location unknown) " ; case x => x }
-        case pos        => "%sat line %s\n%s".format(inFile(other), pos.line, pos.lineContent) + """        /* is shadowed by */"""
-      }
-      def include(v: ValOrDefDef, other: Symbol) = {
-        // shadowing on the same line is a good bet for noise
-        (v.pos == NoPosition || other.pos == NoPosition || v.pos.line != other.pos.line) &&
-        // not likely we'll shadow a whole package without realizing it
-        !other.isPackage &&
-        // (v.symbol == null || !v.symbol.hasTransOwner(other)) &&
-        filt(other)
-      }
-
-      tree match {
-        // while I try to figure out how to limit the noise far enough to make this
-        // genuinely useful, I'm setting minimum identifier length to 3 to omit all
-        // those x's and i's we so enjoy reusing.
-        case v: ValOrDefDef if v.name.toString.length > 2 =>
-          namesWhatIdent(v.name) map { other =>
-            if (include(v, other) && unit != null) {
-              val fstr = "%s (%s) shadows usage %s"
-              unit.warning(v.pos, fstr.format(v.name, v.tpt, positionStr(other)))
-            }
-          }
-        case _ =>
-      }
-    }
-
     def typedUseCase(useCase: UseCase) {
       def stringParser(str: String): syntaxAnalyzer.Parser = {
         val file = new BatchSourceFile(context.unit.source.file, str) {
@@ -1793,15 +1722,6 @@ trait Typers { self: Analyzer =>
     def typedDefDef(ddef: DefDef): DefDef = {
       val meth = ddef.symbol
 
-      // If warnings are enabled, attempt to alert about variable shadowing.  This only
-      // catches method parameters shadowing identifiers declared in the same file, so more
-      // work is needed.  Most of the code here is to filter out false positives.
-      def isAuxConstructor(sym: Symbol) = sym.isConstructor && !sym.isPrimaryConstructor
-      if (settings.YwarnShadow.value && !isAuxConstructor(ddef.symbol)) {
-        for (v <- ddef.vparamss.flatten ; if v.symbol != null && !(v.symbol hasFlag SYNTHETIC))
-          checkShadowings(v, (sym => !sym.isDeferred && !sym.isMethod))
-      }
-
       reenterTypeParams(ddef.tparams)
       reenterValueParams(ddef.vparamss)
 
@@ -1933,7 +1853,6 @@ trait Typers { self: Analyzer =>
           while ((e ne null) && (e.sym ne stat.symbol)) e = e.tail
           if (e eq null) context.scope.enter(stat.symbol)
         }
-        if (settings.YwarnShadow.value) checkShadowings(stat)
         enterLabelDef(stat)
       }
       if (phaseId(currentPeriod) <= currentRun.typerPhase.id) {
@@ -3114,13 +3033,6 @@ trait Typers { self: Analyzer =>
           if (vble == NoSymbol)
             vble = context.owner.newValue(tree.pos, name)
           if (vble.name.toTermName != nme.WILDCARD) {
-/*
-          if (namesSomeIdent(vble.name))
-            context.warning(tree.pos,
-              "pattern variable"+vble.name+" shadows a value visible in the environment;\n"+
-              "use backquotes `"+vble.name+"` if you mean to match against that value;\n" +
-              "or rename the variable or use an explicit bind "+vble.name+"@_ to avoid this warning.")
-*/
             if ((mode & ALTmode) != 0)
               error(tree.pos, "illegal variable in pattern alternative")
             vble = namer.enterInScope(vble)
diff --git a/test/files/neg/migration28.flags b/test/files/neg/migration28.flags
index f7025d0226..197b3198c8 100644
--- a/test/files/neg/migration28.flags
+++ b/test/files/neg/migration28.flags
@@ -1 +1 @@
--Yfatal-warnings -Xmigration
+-Xfatal-warnings -Xmigration
diff --git a/test/files/neg/t3115.flags b/test/files/neg/t3115.flags
index bf8f88334b..d1b831ea87 100644
--- a/test/files/neg/t3115.flags
+++ b/test/files/neg/t3115.flags
@@ -1 +1 @@
--deprecation -Yfatal-warnings
\ No newline at end of file
+-deprecation -Xfatal-warnings
\ No newline at end of file
diff --git a/test/files/pos/bug3097.flags b/test/files/pos/bug3097.flags
index 570b15929d..144ddac9d3 100644
--- a/test/files/pos/bug3097.flags
+++ b/test/files/pos/bug3097.flags
@@ -1 +1 @@
--unchecked -Yfatal-warnings
+-unchecked -Xfatal-warnings