Merge pull request #7724 from som-snytt/issue/unusages

Unused imports and serial ID

build.sbt

@@ -152,6 +152,7 @@ lazy val commonSettings = instanceSettings ++ clearSourceAndResourceDirectories
   cleanFiles += (target in Compile in doc).value,
   fork in run := true,
   connectInput in run := true,
+  //scalacOptions in Compile += "-deprecation",
   //scalacOptions in Compile += "-Xlint:-nullary-override,-inaccessible,-nonlocal-return,_",
   //scalacOptions ++= Seq("-Xmaxerrs", "5", "-Xmaxwarns", "5"),
   scalacOptions in Compile in doc ++= Seq(

src/compiler/scala/reflect/macros/compiler/Errors.scala

@@ -105,7 +105,7 @@ trait Errors extends Traces {
       val verbose = macroDebugVerbose
 
       def check(rtpe: Type, atpe: Type): Boolean = {
-        def success() = { if (verbose) println(rtpe + " <: " + atpe + "?" + EOL + "true"); true }
+        def success() = { if (verbose) println(f"$rtpe <: $atpe?%ntrue"); true }
         (rtpe, atpe) match {
           case _ if rtpe eq atpe => success()
           case (TypeRef(_, RepeatedParamClass, rtpe :: Nil), TypeRef(_, RepeatedParamClass, atpe :: Nil)) => check(rtpe, atpe)

src/compiler/scala/reflect/reify/codegen/GenUtils.scala

@@ -42,7 +42,7 @@ trait GenUtils {
   def call(fname: String, args: Tree*): Tree =
     Apply(termPath(fname), args.toList)
 
-  def mirrorSelect(name: String): Tree   = termPath(nme.UNIVERSE_PREFIX + name)
+  def mirrorSelect(name: String): Tree   = termPath(nme.UNIVERSE_PREFIX.decoded + name)
   def mirrorSelect(name: TermName): Tree = mirrorSelect(name.toString)
 
   def mirrorMirrorSelect(name: TermName): Tree =

src/compiler/scala/tools/nsc/Global.scala

@@ -414,7 +414,7 @@ class Global(var currentSettings: Settings, reporter0: LegacyReporter)
         inform("[running phase " + name + " on " + unit + "]")
     }
 
-    @deprecated
+    @deprecated("Unused, inlined in applyPhase", since="2.13")
     final def withCurrentUnit(unit: CompilationUnit)(task: => Unit): Unit = {
       beforeUnit(unit)
       if (!cancelled(unit)) {
@@ -425,6 +425,7 @@ class Global(var currentSettings: Settings, reporter0: LegacyReporter)
     }
 
     @inline
+    @deprecated("Unused, see withCurrentUnit", since="2.13")
     final def withCurrentUnitNoLog(unit: CompilationUnit)(task: => Unit): Unit = {
       val unit0 = currentUnit
       try {

src/compiler/scala/tools/nsc/ast/NodePrinters.scala

@@ -205,7 +205,7 @@ abstract class NodePrinters {
       else if (trees.tail.isEmpty)
         traverse(trees.head)
       else {
-        printLine("", trees.length + " " + what + "s")
+        printLine("", "" + trees.length + " " + what + "s")
         trees foreach traverse
       }
     }
@@ -295,7 +295,7 @@ abstract class NodePrinters {
                 printLine("", "1 parameter list")
                 ps foreach traverse
               case pss        =>
-                printLine("", pss.length + " parameter lists")
+                printLine("", "" + pss.length + " parameter lists")
                 pss foreach (ps => traverseList("()", "parameter")(ps))
             }
             traverse(tpt)

src/compiler/scala/tools/nsc/ast/TreeGen.scala

@@ -17,6 +17,7 @@ import scala.collection.mutable.ListBuffer
 import symtab.Flags._
 import scala.language.postfixOps
 import scala.reflect.internal.util.FreshNameCreator
+import scala.reflect.internal.util.ListOfNil
 
 /** XXX to resolve: TreeGen only assumes global is a SymbolTable, but
  *  TreeDSL at the moment expects a Global.  Can we get by with SymbolTable?

src/compiler/scala/tools/nsc/backend/jvm/BTypesFromSymbols.scala

@@ -481,7 +481,7 @@ abstract class BTypesFromSymbols[G <: Global](val global: G) extends BTypes {
       // phase travel necessary: after flatten, the name includes the name of outer classes.
       // if some outer name contains $anon, a non-anon class is considered anon.
       if (exitingPickler(innerClassSym.isAnonymousClass || innerClassSym.isAnonymousFunction)) None
-      else Some(innerClassSym.rawname + innerClassSym.moduleSuffix) // moduleSuffix for module classes
+      else Some(s"${innerClassSym.rawname}${innerClassSym.moduleSuffix}") // moduleSuffix for module classes
     }
 
     Some(NestedInfo(enclosingClass, outerName, innerName, isStaticNestedClass))

src/compiler/scala/tools/nsc/backend/jvm/BackendReporting.scala

@@ -36,16 +36,10 @@ object BackendReporting {
   def assertionError(message: String): Nothing = throw new AssertionError(message)
 
   implicit class RightBiasedEither[A, B](val v: Either[A, B]) extends AnyVal {
-    def withFilter(f: B => Boolean)(implicit empty: A): Either[A, B] = v match {
-      case Left(_)  => v
-      case Right(e) => if (f(e)) v else Left(empty) // scalaz.\/ requires an implicit Monoid m to get m.empty
-    }
+    def withFilter(f: B => Boolean)(implicit empty: A): Either[A, B] = v.filterOrElse(f, empty)
 
     /** Get the value, fail with an assertion if this is an error. */
-    def get: B = {
-      assert(v.isRight, v.left.get)
-      v.right.get
-    }
+    def get: B = v.fold(a => assertionError(s"$a"), identity)
 
     /**
      * Get the right value of an `Either` by throwing a potential error message. Can simplify the
@@ -56,10 +50,7 @@ object BackendReporting {
      *       eitherOne.orThrow .... eitherTwo.orThrow ... eitherThree.orThrow
      *     }
      */
-    def orThrow: B = v match {
-      case Left(m)  => throw Invalid(m)
-      case Right(t) => t
-    }
+    def orThrow: B = v.fold(a => throw Invalid(a), identity)
   }
 
   case class Invalid[A](e: A) extends ControlThrowable
@@ -73,11 +64,13 @@ object BackendReporting {
     def emitWarning(settings: CompilerSettings): Boolean
   }
 
-  // Method withFilter in RightBiasedEither requires an implicit empty value. Taking the value here
-  // in scope allows for-comprehensions that desugar into withFilter calls (for example when using a
-  // tuple de-constructor).
-  implicit object emptyOptimizerWarning extends OptimizerWarning {
-    def emitWarning(settings: CompilerSettings): Boolean = false
+  object OptimizerWarning {
+    // Method withFilter in RightBiasedEither requires an implicit empty value. Taking the value here
+    // in scope allows for-comprehensions that desugar into withFilter calls (for example when using a
+    // tuple de-constructor).
+    implicit val emptyOptimizerWarning: OptimizerWarning = new OptimizerWarning {
+      def emitWarning(settings: CompilerSettings): Boolean = false
+    }
   }
 
   sealed trait MissingBytecodeWarning extends OptimizerWarning {
@@ -116,11 +109,11 @@ object BackendReporting {
     }
   }
 
-  case class ClassNotFound(internalName: InternalName, definedInJavaSource: Boolean) extends MissingBytecodeWarning
-  case class MethodNotFound(name: String, descriptor: String, ownerInternalNameOrArrayDescriptor: InternalName, missingClass: Option[ClassNotFound]) extends MissingBytecodeWarning {
+  final case class ClassNotFound(internalName: InternalName, definedInJavaSource: Boolean) extends MissingBytecodeWarning
+  final case class MethodNotFound(name: String, descriptor: String, ownerInternalNameOrArrayDescriptor: InternalName, missingClass: Option[ClassNotFound]) extends MissingBytecodeWarning {
     def isArrayMethod = ownerInternalNameOrArrayDescriptor.charAt(0) == '['
   }
-  case class FieldNotFound(name: String, descriptor: String, ownerInternalName: InternalName, missingClass: Option[ClassNotFound]) extends MissingBytecodeWarning
+  final case class FieldNotFound(name: String, descriptor: String, ownerInternalName: InternalName, missingClass: Option[ClassNotFound]) extends MissingBytecodeWarning
 
   sealed trait NoClassBTypeInfo extends OptimizerWarning {
     override def toString = this match {
@@ -137,8 +130,8 @@ object BackendReporting {
     }
   }
 
-  case class NoClassBTypeInfoMissingBytecode(cause: MissingBytecodeWarning) extends NoClassBTypeInfo
-  case class NoClassBTypeInfoClassSymbolInfoFailedSI9111(classFullName: String) extends NoClassBTypeInfo
+  final case class NoClassBTypeInfoMissingBytecode(cause: MissingBytecodeWarning) extends NoClassBTypeInfo
+  final case class NoClassBTypeInfoClassSymbolInfoFailedSI9111(classFullName: String) extends NoClassBTypeInfo
 
   /**
    * Used in the CallGraph for nodes where an issue occurred determining the callee information.
@@ -172,9 +165,9 @@ object BackendReporting {
     }
   }
 
-  case class MethodInlineInfoIncomplete(declarationClass: InternalName, name: String, descriptor: String, cause: ClassInlineInfoWarning) extends CalleeInfoWarning
-  case class MethodInlineInfoMissing(declarationClass: InternalName, name: String, descriptor: String, cause: Option[ClassInlineInfoWarning]) extends CalleeInfoWarning
-  case class MethodInlineInfoError(declarationClass: InternalName, name: String, descriptor: String, cause: NoClassBTypeInfo) extends CalleeInfoWarning
+  final case class MethodInlineInfoIncomplete(declarationClass: InternalName, name: String, descriptor: String, cause: ClassInlineInfoWarning) extends CalleeInfoWarning
+  final case class MethodInlineInfoMissing(declarationClass: InternalName, name: String, descriptor: String, cause: Option[ClassInlineInfoWarning]) extends CalleeInfoWarning
+  final case class MethodInlineInfoError(declarationClass: InternalName, name: String, descriptor: String, cause: NoClassBTypeInfo) extends CalleeInfoWarning
 
   sealed trait CannotInlineWarning extends OptimizerWarning {
     def calleeDeclarationClass: InternalName
@@ -226,22 +219,22 @@ object BackendReporting {
         annotatedInline && settings.optWarningEmitAtInlineFailed
     }
   }
-  case class CalleeNotFinal(calleeDeclarationClass: InternalName, name: String, descriptor: String,  annotatedInline: Boolean) extends CannotInlineWarning
-  case class IllegalAccessInstructions(calleeDeclarationClass: InternalName, name: String, descriptor: String, annotatedInline: Boolean,
+  final case class CalleeNotFinal(calleeDeclarationClass: InternalName, name: String, descriptor: String,  annotatedInline: Boolean) extends CannotInlineWarning
+  final case class IllegalAccessInstructions(calleeDeclarationClass: InternalName, name: String, descriptor: String, annotatedInline: Boolean,
                                        callsiteClass: InternalName, instructions: List[AbstractInsnNode]) extends CannotInlineWarning
-  case class IllegalAccessCheckFailed(calleeDeclarationClass: InternalName, name: String, descriptor: String, annotatedInline: Boolean,
+  final case class IllegalAccessCheckFailed(calleeDeclarationClass: InternalName, name: String, descriptor: String, annotatedInline: Boolean,
                                       callsiteClass: InternalName, instruction: AbstractInsnNode, cause: OptimizerWarning) extends CannotInlineWarning
-  case class MethodWithHandlerCalledOnNonEmptyStack(calleeDeclarationClass: InternalName, name: String, descriptor: String, annotatedInline: Boolean,
+  final case class MethodWithHandlerCalledOnNonEmptyStack(calleeDeclarationClass: InternalName, name: String, descriptor: String, annotatedInline: Boolean,
                                                     callsiteClass: InternalName, callsiteName: String, callsiteDesc: String) extends CannotInlineWarning
-  case class SynchronizedMethod(calleeDeclarationClass: InternalName, name: String, descriptor: String, annotatedInline: Boolean) extends CannotInlineWarning
-  case class StrictfpMismatch(calleeDeclarationClass: InternalName, name: String, descriptor: String, annotatedInline: Boolean,
+  final case class SynchronizedMethod(calleeDeclarationClass: InternalName, name: String, descriptor: String, annotatedInline: Boolean) extends CannotInlineWarning
+  final case class StrictfpMismatch(calleeDeclarationClass: InternalName, name: String, descriptor: String, annotatedInline: Boolean,
                               callsiteClass: InternalName, callsiteName: String, callsiteDesc: String) extends CannotInlineWarning
   case class ResultingMethodTooLarge(calleeDeclarationClass: InternalName, name: String, descriptor: String, annotatedInline: Boolean,
                                      callsiteClass: InternalName, callsiteName: String, callsiteDesc: String) extends CannotInlineWarning
 
   // TODO: this should be a subtype of CannotInlineWarning
   // but at the place where it's created (in findIllegalAccess) we don't have the necessary data (calleeName, calleeDescriptor).
-  case object UnknownInvokeDynamicInstruction extends OptimizerWarning {
+  final case object UnknownInvokeDynamicInstruction extends OptimizerWarning {
     override def toString = "The callee contains an InvokeDynamic instruction with an unknown bootstrap method (not a LambdaMetaFactory)."
     def emitWarning(settings: CompilerSettings): Boolean = settings.optWarningEmitAnyInlineFailed
   }
@@ -265,8 +258,8 @@ object BackendReporting {
         s"The closure body invocation cannot be rewritten because the target method is not accessible in class $callsiteClass."
     }
   }
-  case class RewriteClosureAccessCheckFailed(pos: Position, cause: OptimizerWarning) extends RewriteClosureApplyToClosureBodyFailed
-  case class RewriteClosureIllegalAccess(pos: Position, callsiteClass: InternalName) extends RewriteClosureApplyToClosureBodyFailed
+  final case class RewriteClosureAccessCheckFailed(pos: Position, cause: OptimizerWarning) extends RewriteClosureApplyToClosureBodyFailed
+  final case class RewriteClosureIllegalAccess(pos: Position, callsiteClass: InternalName) extends RewriteClosureApplyToClosureBodyFailed
 
   /**
    * Used in the InlineInfo of a ClassBType, when some issue occurred obtaining the inline information.
@@ -294,8 +287,8 @@ object BackendReporting {
     }
   }
 
-  case class NoInlineInfoAttribute(internalName: InternalName) extends ClassInlineInfoWarning
-  case class ClassSymbolInfoFailureSI9111(classFullName: String) extends ClassInlineInfoWarning
-  case class ClassNotFoundWhenBuildingInlineInfoFromSymbol(missingClass: ClassNotFound) extends ClassInlineInfoWarning
-  case class UnknownScalaInlineInfoVersion(internalName: InternalName, version: Int) extends ClassInlineInfoWarning
+  final case class NoInlineInfoAttribute(internalName: InternalName) extends ClassInlineInfoWarning
+  final case class ClassSymbolInfoFailureSI9111(classFullName: String) extends ClassInlineInfoWarning
+  final case class ClassNotFoundWhenBuildingInlineInfoFromSymbol(missingClass: ClassNotFound) extends ClassInlineInfoWarning
+  final case class UnknownScalaInlineInfoVersion(internalName: InternalName, version: Int) extends ClassInlineInfoWarning
 }

src/compiler/scala/tools/nsc/backend/jvm/analysis/BackendUtils.scala

@@ -20,6 +20,7 @@ import java.util.concurrent.ConcurrentHashMap
 import scala.annotation.{switch, tailrec}
 import scala.collection.JavaConverters._
 import scala.collection.immutable.BitSet
+import scala.collection.immutable.ArraySeq.unsafeWrapArray
 import scala.collection.mutable
 import scala.reflect.internal.util.Position
 import scala.tools.asm
@@ -139,11 +140,11 @@ abstract class BackendUtils extends PerRunInit {
     }
     for ((label, i) <- initialLabels.iterator.zipWithIndex) {
       mv.visitLabel(label)
-      emitLambdaDeserializeIndy(groups(i))
+      emitLambdaDeserializeIndy(unsafeWrapArray(groups(i)))
       mv.visitInsn(ARETURN)
     }
     mv.visitLabel(terminalLabel)
-    emitLambdaDeserializeIndy(groups(numGroups - 1))
+    emitLambdaDeserializeIndy(unsafeWrapArray(groups(numGroups - 1)))
     mv.visitInsn(ARETURN)
   }
 

src/compiler/scala/tools/nsc/classpath/VirtualDirectoryClassPath.scala

@@ -25,7 +25,7 @@ case class VirtualDirectoryClassPath(dir: VirtualDirectory) extends ClassPath wi
 
   protected def emptyFiles: Array[AbstractFile] = Array.empty
   protected def getSubDir(packageDirName: String): Option[AbstractFile] =
-    Option(AbstractFileClassLoader.lookupPath(dir)(packageDirName.split('/'), directory = true))
+    Option(AbstractFileClassLoader.lookupPath(dir)(packageDirName.split('/').toIndexedSeq, directory = true))
   protected def listChildren(dir: AbstractFile, filter: Option[AbstractFile => Boolean] = None): Array[F] = filter match {
     case Some(f) => dir.iterator.filter(f).toArray
     case _ => dir.toArray
@@ -41,7 +41,7 @@ case class VirtualDirectoryClassPath(dir: VirtualDirectory) extends ClassPath wi
 
   def findClassFile(className: String): Option[AbstractFile] = {
     val relativePath = FileUtils.dirPath(className) + ".class"
-    Option(AbstractFileClassLoader.lookupPath(dir)(relativePath split '/', directory = false))
+    Option(AbstractFileClassLoader.lookupPath(dir)(relativePath.split('/').toIndexedSeq, directory = false))
   }
 
   private[nsc] def classes(inPackage: String): Seq[ClassFileEntry] = files(inPackage)

src/compiler/scala/tools/nsc/fsc/CompileServer.scala

@@ -84,7 +84,7 @@ class StandardCompileServer(fixPort: Int = 0) extends SocketServer(fixPort) {
     val input           = in.readLine()
 
     def fscError(msg: String): Unit = out println (
-      FakePos("fsc") + msg + "\n  fsc -help  gives more information"
+      "" + FakePos("fsc") + msg + "\n  fsc -help  gives more information"
     )
     if (input == null || password != guessedPassword)
       return

src/compiler/scala/tools/nsc/symtab/BrowsingLoaders.scala

@@ -53,7 +53,7 @@ abstract class BrowsingLoaders extends GlobalSymbolLoaders {
         val memberSourceFile = member.sourceFile
         if (memberSourceFile != null) {
           if (existingSourceFile != memberSourceFile)
-            error(member+"is defined twice,"+
+            error(""+member+"is defined twice,"+
               "\n in "+existingSourceFile+
               "\n and also in "+memberSourceFile)
         }

src/compiler/scala/tools/nsc/symtab/SymbolTrackers.scala

@@ -138,7 +138,7 @@ trait SymbolTrackers {
           val s = sym.defString take 240
           if (s.length == 240) s + "..." else s
         }
-        else sym + changedOwnerString + flagSummaryString
+        else "" + sym + changedOwnerString + flagSummaryString
       )
 
       def flatten = children.foldLeft(Set(root))(_ ++ _.flatten)

src/compiler/scala/tools/nsc/symtab/classfile/ClassfileParser.scala

@@ -619,7 +619,7 @@ abstract class ClassfileParser {
                    * If symbol 1 gets completed (e.g. because the compiled source mentions `A$B`, not `A#B`), the
                    * ClassfileParser for 1 executes, and clazz.owner is the package.
                    */
-                  assert(params.head.tpe.typeSymbol == clazz.owner || clazz.owner.hasPackageFlag, params.head.tpe.typeSymbol + ": " + clazz.owner)
+                  assert(params.head.tpe.typeSymbol == clazz.owner || clazz.owner.hasPackageFlag, "" + params.head.tpe.typeSymbol + ": " + clazz.owner)
                   removedOuterParameter = true
                   params.tail
                 case _ =>
@@ -907,6 +907,7 @@ abstract class ClassfileParser {
           parseExceptions(attrLen)
 
         case tpnme.SourceFileATTR =>
+          /*
           if (forInteractive) {
             // opt: disable this code in the batch compiler for performance reasons.
             // it appears to be looking for the .java source file mentioned in this attribute
@@ -927,6 +928,8 @@ abstract class ClassfileParser {
             }
             srcfile0 = settings.outputDirs.srcFilesFor(in.file, srcpath).find(_.exists)
           } else in.skip(attrLen)
+          */
+          in.skip(attrLen)
 
         case tpnme.CodeATTR =>
           if (sym.owner.isInterface) {