Support JDK 17 PermittedSubclasses in classfiles

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

@@ -1727,10 +1727,8 @@ class Global(var currentSettings: Settings, reporter0: Reporter)
   } // class Run
 
   def printAllUnits(): Unit = {
-    print("[[syntax trees at end of %25s]]".format(phase))
-    exitingPhase(phase)(currentRun.units foreach { unit =>
-      nodePrinters showUnit unit
-    })
+    print(f"[[syntax trees at end of $phase%25s]]")
+    exitingPhase(phase)(currentRun.units.foreach(nodePrinters.showUnit(_)))
   }
 
   /** We resolve the class/object ambiguity by passing a type/term name.

src/compiler/scala/tools/nsc/ast/parser/CommonTokens.scala

@@ -51,7 +51,7 @@ abstract class CommonTokens {
   // J: PUBLIC = 42
   final val PROTECTED = 43
   final val PRIVATE = 44
-  // S: SEALED = 45
+  final val SEALED = 45     // J: contextual keyword
   final val ABSTRACT = 46
   // J: DEFAULT = 47
   // J: STATIC = 48

src/compiler/scala/tools/nsc/ast/parser/Tokens.scala

@@ -28,7 +28,6 @@ object Tokens extends CommonTokens {
   /** modifiers */
   final val IMPLICIT = 40
   final val OVERRIDE = 41
-  final val SEALED = 45
   final val LAZY = 55
   final val MACRO = 57
 

src/compiler/scala/tools/nsc/javac/JavaParsers.scala

@@ -16,14 +16,14 @@
 package scala.tools.nsc
 package javac
 
-import scala.collection.mutable.ListBuffer
 import symtab.Flags
 import JavaTokens._
-import scala.annotation.tailrec
+import scala.annotation._
+import scala.collection.mutable.ListBuffer
 import scala.language.implicitConversions
-import scala.reflect.internal.util.Position
-import scala.reflect.internal.util.ListOfNil
+import scala.reflect.internal.util.{ListOfNil, Position}
 import scala.tools.nsc.Reporting.WarningCategory
+import scala.util.chaining._
 
 trait JavaParsers extends ast.parser.ParsersCommon with JavaScanners {
   val global : Global
@@ -493,11 +493,39 @@ trait JavaParsers extends ast.parser.ParsersCommon with JavaScanners {
           case SYNCHRONIZED =>
             in.nextToken()
           case _ =>
-            val privateWithin: TypeName =
-              if (isPackageAccess && !inInterface) thisPackageName
-              else tpnme.EMPTY
-
-            return Modifiers(flags, privateWithin) withAnnotations annots
+            val unsealed = 0L   // no flag for UNSEALED
+            def consume(added: FlagSet): false = { in.nextToken(); /*flags |= added;*/ false }
+            def lookingAhead(s: String): Boolean = {
+              import scala.reflect.internal.Chars._
+              var i = 0
+              val n = s.length
+              val lookahead = in.in.lookahead
+              while (i < n && lookahead.ch != SU) {
+                if (lookahead.ch != s.charAt(i)) return false
+                lookahead.next()
+                i += 1
+              }
+              i == n && Character.isWhitespace(lookahead.ch)
+            }
+            val done = (in.token != IDENTIFIER) || (
+              in.name match {
+                case nme.javaRestrictedIdentifiers.SEALED => consume(Flags.SEALED)
+                case nme.javaRestrictedIdentifiers.UNSEALED => consume(unsealed)
+                case nme.javaRestrictedIdentifiers.NON =>
+                  !lookingAhead("-sealed") || {
+                    in.nextToken()
+                    in.nextToken()
+                    consume(unsealed)
+                  }
+                case _ => true
+              }
+            )
+            if (done) {
+              val privateWithin: TypeName =
+                if (isPackageAccess && !inInterface) thisPackageName
+                else tpnme.EMPTY
+              return Modifiers(flags, privateWithin) withAnnotations annots
+            }
         }
       }
       abort("should not be here")
@@ -802,6 +830,13 @@ trait JavaParsers extends ast.parser.ParsersCommon with JavaScanners {
         List()
       }
 
+    def permitsOpt() =
+      if (in.token == IDENTIFIER && in.name == nme.javaRestrictedIdentifiers.PERMITS) {
+        in.nextToken()
+        repsep(() => typ(), COMMA)
+      }
+      else Nil
+
     def classDecl(mods: Modifiers): List[Tree] = {
       accept(CLASS)
       val pos = in.currentPos
@@ -815,9 +850,11 @@ trait JavaParsers extends ast.parser.ParsersCommon with JavaScanners {
           javaLangObject()
         }
       val interfaces = interfacesOpt()
+      val permits = permitsOpt()
       val (statics, body) = typeBody(CLASS)
       addCompanionObject(statics, atPos(pos) {
         ClassDef(mods, name, tparams, makeTemplate(superclass :: interfaces, body))
+          .tap(cd => if (permits.nonEmpty) cd.updateAttachment(PermittedSubclasses(permits)))
       })
     }
 
@@ -878,11 +915,13 @@ trait JavaParsers extends ast.parser.ParsersCommon with JavaScanners {
         } else {
           List(javaLangObject())
         }
+      val permits = permitsOpt()
       val (statics, body) = typeBody(INTERFACE)
       addCompanionObject(statics, atPos(pos) {
         ClassDef(mods | Flags.TRAIT | Flags.INTERFACE | Flags.ABSTRACT,
                  name, tparams,
                  makeTemplate(parents, body))
+          .tap(cd => if (permits.nonEmpty) cd.updateAttachment(PermittedSubclasses(permits)))
       })
     }
 
@@ -905,7 +944,6 @@ trait JavaParsers extends ast.parser.ParsersCommon with JavaScanners {
         } else if (in.token == SEMI) {
           in.nextToken()
         } else {
-
           // See "14.3. Local Class and Interface Declarations"
           adaptRecordIdentifier()
           if (in.token == ENUM || in.token == RECORD || definesInterface(in.token))

src/compiler/scala/tools/nsc/javac/JavaTokens.scala

@@ -38,6 +38,7 @@ object JavaTokens extends ast.parser.CommonTokens {
   final val NATIVE = 53
   final val STRICTFP = 54
   final val THROWS = 56
+  final val UNSEALED = 57   // contextual keyword
 
   /** templates */
   final val INTERFACE = 66

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

@@ -853,10 +853,11 @@ abstract class ClassfileParser(reader: ReusableInstance[ReusableDataReader]) {
           in.skip(attrLen)
 
         case tpnme.RuntimeAnnotationATTR =>
-            val numAnnots = u2()
+          val numAnnots = u2()
           val annots = new ListBuffer[AnnotationInfo]
-          for (n <- 0 until numAnnots; annot <- parseAnnotation(u2()))
-            annots += annot
+          numAnnots times {
+            parseAnnotation(u2()).foreach(annots.addOne)
+          }
           /* `sym.withAnnotations(annots)`, like `sym.addAnnotation(annot)`, prepends,
            * so if we parsed in classfile order we would wind up with the annotations
            * in reverse order in `sym.annotations`. Instead we just read them out the
@@ -905,6 +906,17 @@ abstract class ClassfileParser(reader: ReusableInstance[ReusableDataReader]) {
           }
           in.skip(attrLen)
 
+        case tpnme.PermittedSubclassesATTR =>
+          sym.setFlag(SEALED)
+          val numberOfClasses = u2()
+          numberOfClasses times {
+            val k = pool.getClassSymbol(u2())
+            completer match {
+              case ctc: ClassTypeCompleter => ctc.permittedSubclasses ::= k   // sym.addChild(k)
+              case _ =>
+            }
+          }
+
         case _ =>
           in.skip(attrLen)
       }
@@ -1357,6 +1369,7 @@ abstract class ClassfileParser(reader: ReusableInstance[ReusableDataReader]) {
     var exceptions: List[NameOrString] = Nil
   }
   private final class ClassTypeCompleter(name: Name, jflags: JavaAccFlags, parent: NameOrString, ifaces: List[NameOrString]) extends JavaTypeCompleter {
+    var permittedSubclasses: List[symbolTable.Symbol] = Nil
     override def complete(sym: symbolTable.Symbol): Unit = {
       val info = if (sig != null) sigToType(sym, sig) else {
         val superTpe = if (parent == null) definitions.AnyClass.tpe_* else getClassSymbol(parent.value).tpe_*
@@ -1365,6 +1378,9 @@ abstract class ClassfileParser(reader: ReusableInstance[ReusableDataReader]) {
         ClassInfoType(superTpe1 :: ifacesTypes, instanceScope, clazz)
       }
       sym.setInfo(info)
+      for (k <- permittedSubclasses)
+        if (k.parentSymbols.contains(sym))
+          sym.addChild(k)
     }
   }
 
@@ -1494,7 +1510,13 @@ abstract class ClassfileParser(reader: ReusableInstance[ReusableDataReader]) {
     if (flags.isStatic) staticScope else instanceScope
 }
 object ClassfileParser {
-  private implicit class GoodTimes(val n: Int) extends AnyVal {
-    def times(body: => Unit) = (1 to n).foreach(_ => body)
+  private implicit class GoodTimes(private val n: Int) extends AnyVal {
+    def times(body: => Unit): Unit = {
+      var i = n
+      while (i > 0) {
+        body
+        i -= 1
+      }
+    }
   }
 }

src/compiler/scala/tools/nsc/typechecker/ContextErrors.scala

@@ -885,7 +885,7 @@ trait ContextErrors extends splain.SplainErrors {
 
       // def stabilize
       def NotAValueError(tree: Tree, sym: Symbol) = {
-        issueNormalTypeError(tree, sym.kindString + " " + sym.fullName + " is not a value")
+        issueNormalTypeError(tree, s"${sym.kindString} ${sym.fullName} is not a value")
         setError(tree)
       }
 

src/compiler/scala/tools/nsc/typechecker/Namers.scala

@@ -427,29 +427,27 @@ trait Namers extends MethodSynthesis {
     /** Given a ClassDef or ModuleDef, verifies there isn't a companion which
      *  has been defined in a separate file.
      */
-    @nowarn("cat=lint-nonlocal-return")
     def validateCompanionDefs(tree: ImplDef): Unit = {
-      val sym    = tree.symbol orElse { return }
-      val ctx    = if (context.owner.isPackageObjectClass) context.outer else context
-      val module = if (sym.isModule) sym else ctx.scope lookupModule tree.name
-      val clazz  = if (sym.isClass) sym else ctx.scope lookupClass tree.name
-      val fails  = (
-           module.isModule
-        && clazz.isClass
-        && !module.isSynthetic
-        && !clazz.isSynthetic
-        && (clazz.sourceFile ne null)
-        && (module.sourceFile ne null)
-        && !(module isCoDefinedWith clazz)
-        && module.exists
-        && clazz.exists
-        && (currentRun.compiles(clazz) == currentRun.compiles(module))
-      )
-      if (fails) {
-        reporter.error(tree.pos, (
-            s"Companions '$clazz' and '$module' must be defined in same file:\n"
-          + s"  Found in ${clazz.sourceFile.canonicalPath} and ${module.sourceFile.canonicalPath}")
+      val sym = tree.symbol
+      if (sym != NoSymbol) {
+        val ctx    = if (context.owner.isPackageObjectClass) context.outer else context
+        val module = if (sym.isModule) sym else ctx.scope.lookupModule(tree.name)
+        val clazz  = if (sym.isClass) sym else ctx.scope.lookupClass(tree.name)
+        val fails  = (
+             module.isModule
+          && clazz.isClass
+          && !module.isSynthetic
+          && !clazz.isSynthetic
+          && (clazz.sourceFile ne null)
+          && (module.sourceFile ne null)
+          && !module.isCoDefinedWith(clazz)
+          && module.exists
+          && clazz.exists
+          && currentRun.compiles(clazz) == currentRun.compiles(module)
         )
+        if (fails) reporter.error(tree.pos,
+          sm"""|Companions '$clazz' and '$module' must be defined in same file:
+               |  Found in ${clazz.sourceFile.canonicalPath} and ${module.sourceFile.canonicalPath}""")
       }
     }
 
@@ -1186,17 +1184,25 @@ trait Namers extends MethodSynthesis {
       val pending = mutable.ListBuffer[AbsTypeError]()
       parentTrees foreach { tpt =>
         val ptpe = tpt.tpe
-        if (!ptpe.isError) {
+        if (!ptpe.isError && !phase.erasedTypes) {
           val psym = ptpe.typeSymbol
-          val sameSourceFile = context.unit.source.file == psym.sourceFile
-
-          if (psym.isSealed && !phase.erasedTypes)
-            if (sameSourceFile)
-              psym addChild context.owner
+          if (psym.isSealed) {
+            val sameSourceFile = context.unit.source.file == psym.sourceFile
+            val okChild =
+              if (psym.isJava)
+                psym.attachments.get[PermittedSubclassSymbols] match {
+                  case Some(permitted) => permitted.permits.exists(_ == clazz)
+                  case _ => sameSourceFile
+                }
+              else
+                sameSourceFile
+            if (okChild)
+              psym.addChild(clazz)
             else
               pending += ParentSealedInheritanceError(tpt, psym)
-          if (psym.isLocalToBlock && psym.isClass && !phase.erasedTypes)
-            psym addChild context.owner
+          }
+          if (psym.isLocalToBlock && psym.isClass)
+            psym.addChild(clazz)
         }
       }
       pending.foreach(ErrorUtils.issueTypeError)
@@ -1214,13 +1220,12 @@ trait Namers extends MethodSynthesis {
 
       // add apply and unapply methods to companion objects of case classes,
       // unless they exist already; here, "clazz" is the module class
-      if (clazz.isModuleClass) {
+      if (clazz.isModuleClass)
         clazz.attachments.get[ClassForCaseCompanionAttachment] foreach { cma =>
           val cdef = cma.caseClass
           assert(cdef.mods.isCase, "expected case class: "+ cdef)
           addApplyUnapply(cdef, templateNamer)
         }
-      }
 
       // add the copy method to case classes; this needs to be done here, not in SyntheticMethods, because
       // the namer phase must traverse this copy method to create default getters for its parameters.
@@ -1266,6 +1271,11 @@ trait Namers extends MethodSynthesis {
       val res = GenPolyType(tparams0, resultType)
 
       val pluginsTp = pluginsTypeSig(res, typer, cdef, WildcardType)
+      cdef.getAndRemoveAttachment[PermittedSubclasses].foreach { permitted =>
+        clazz.updateAttachment[PermittedSubclassSymbols] {
+          PermittedSubclassSymbols(permitted.permits.map(typer.typed(_, Mode.NOmode).symbol))
+        }
+      }
 
       // Already assign the type to the class symbol (monoTypeCompleter will do it again).
       // Allows isDerivedValueClass to look at the info.

src/compiler/scala/tools/nsc/typechecker/Typers.scala

@@ -1811,7 +1811,7 @@ trait Typers extends Adaptations with Tags with TypersTracking with PatternTyper
         if (parent == DynamicClass) checkFeature(parentPos, currentRun.runDefinitions.DynamicsFeature)
 
       def validateParentClass(parent: Tree, superclazz: Symbol) =
-        if (!parent.isErrorTyped) {
+        if (!parent.isErrorTyped) { // redundant
           val psym = parent.tpe.typeSymbol.initialize
 
           if (!context.unit.isJava)
@@ -1876,7 +1876,7 @@ trait Typers extends Adaptations with Tags with TypersTracking with PatternTyper
 
       if (!parents.isEmpty && parents.forall(!_.isErrorTyped)) {
         val superclazz = parents.head.tpe.typeSymbol
-        for (p <- parents) validateParentClass(p, superclazz)
+        parents.foreach(validateParentClass(_, superclazz))
       }
 
       pending.foreach(ErrorUtils.issueTypeError)
@@ -2054,7 +2054,7 @@ trait Typers extends Adaptations with Tags with TypersTracking with PatternTyper
       val body1 = pluginsEnterStats(this, namer.expandMacroAnnotations(templ.body))
       enterSyms(context.outer.make(templ, clazz, clazz.info.decls), body1)
       if (!templ.isErrorTyped) // if `parentTypes` has invalidated the template, don't validate it anymore
-      validateParentClasses(parents1, selfType, clazz.isTrait)
+        validateParentClasses(parents1, selfType, clazz.isTrait)
       if (clazz.isCase)
         validateNoCaseAncestor(clazz)
       if (clazz.isTrait && hasSuperArgs(parents1.head))
@@ -2088,11 +2088,10 @@ trait Typers extends Adaptations with Tags with TypersTracking with PatternTyper
         ctors.foreach(AuxConstrInConstantAnnotation(_, clazz))
       }
 
-
       if (clazz.isTrait) {
-        for (decl <- clazz.info.decls if decl.isTerm && decl.isEarlyInitialized) {
-          context.warning(decl.pos, "Implementation restriction: early definitions in traits are not initialized before the super class is initialized.", WarningCategory.Other)
-        }
+        for (decl <- clazz.info.decls)
+          if (decl.isTerm && decl.isEarlyInitialized)
+            context.warning(decl.pos, "Implementation restriction: early definitions in traits are not initialized before the super class is initialized.", WarningCategory.Other)
       }
 
       treeCopy.Template(templ, parents1, self1, body3) setType clazz.tpe_*

src/partest/scala/tools/partest/nest/AbstractRunner.scala

@@ -291,7 +291,7 @@ class AbstractRunner(val config: RunnerSpec.Config, protected final val testSour
             List(pathSettings.testParent / norm)
           }
         }
-        .distinct
+        .distinct.filter(denotesTestPath)
       }
 
       val isRerun = config.optFailed

src/reflect/scala/reflect/internal/StdAttachments.scala

@@ -154,4 +154,8 @@ trait StdAttachments {
   case object FieldTypeInferred extends PlainAttachment
 
   case class LookupAmbiguityWarning(msg: String) extends PlainAttachment
+
+  /** Java sealed classes may be qualified with a permits clause specifying allowed subclasses. */
+  case class PermittedSubclasses(permits: List[Tree]) extends PlainAttachment
+  case class PermittedSubclassSymbols(permits: List[Symbol]) extends PlainAttachment
 }