Accept (non-)sealed in Java

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

@@ -16,13 +16,12 @@
 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
 
 trait JavaParsers extends ast.parser.ParsersCommon with JavaScanners {
@@ -493,11 +492,39 @@ 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 +829,14 @@ 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
@@ -815,6 +850,7 @@ trait JavaParsers extends ast.parser.ParsersCommon with JavaScanners {
           javaLangObject()
         }
       val interfaces = interfacesOpt()
+      @unused val permits = permitsOpt()
       val (statics, body) = typeBody(CLASS)
       addCompanionObject(statics, atPos(pos) {
         ClassDef(mods, name, tparams, makeTemplate(superclass :: interfaces, body))
@@ -878,6 +914,7 @@ trait JavaParsers extends ast.parser.ParsersCommon with JavaScanners {
         } else {
           List(javaLangObject())
         }
+      @unused val permits = permitsOpt()
       val (statics, body) = typeBody(INTERFACE)
       addCompanionObject(statics, atPos(pos) {
         ClassDef(mods | Flags.TRAIT | Flags.INTERFACE | Flags.ABSTRACT,
@@ -905,7 +942,6 @@ 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

@@ -904,6 +904,11 @@ abstract class ClassfileParser(reader: ReusableInstance[ReusableDataReader]) {
           }
           in.skip(attrLen)
 
+        case tpnme.PermittedSubclassesATTR =>
+          debuglog(s"$sym is Java sealed.")
+          sym.setFlag(SEALED)
+          in.skip(attrLen) // https://openjdk.java.net/jeps/360 but ignore permits and respect only Scala semantics
+
         case _ =>
           in.skip(attrLen)
       }

src/reflect/scala/reflect/internal/StdNames.scala

@@ -320,6 +320,7 @@ trait StdNames {
     final val SignatureATTR: NameType              = nameType("Signature")
     final val SourceFileATTR: NameType             = nameType("SourceFile")
     final val SyntheticATTR: NameType              = nameType("Synthetic")
+    final val PermittedSubclassesATTR: NameType    = nameType("PermittedSubclasses")
 
     final val scala_ : NameType = nameType("scala")
 
@@ -1281,7 +1282,11 @@ trait StdNames {
   // A type identifier is an identifier that is not the character sequence var, yield, or record.
   // An unqualified method identifier is an identifier that is not the character sequence yield.
   class JavaRestrictedIdentifiers {
+    final val PERMITS: TermName = TermName("permits")
     final val RECORD: TermName = TermName("record")
+    final val SEALED: TermName = TermName("sealed")
+    final val UNSEALED: TermName = TermName("non-sealed")
+    final val NON: TermName = TermName("non")
     final val VAR: TermName    = TermName("var")
     final val YIELD: TermName  = TermName("yield")
   }

src/reflect/scala/reflect/internal/Trees.scala

@@ -1426,7 +1426,7 @@ trait Trees extends api.Trees {
       else Modifiers(flags, privateWithin, newAnns) setPositions positions
     }
 
-    override def toString = "Modifiers(%s, %s, %s)".format(flagString, annotations mkString ", ", positions)
+    override def toString = s"Modifiers($flagString, ${annotations.mkString(",")}, $positions)"
   }
 
   object Modifiers extends ModifiersExtractor

test/files/neg/t12159.check

@@ -0,0 +1,7 @@
+s.scala:5: error: illegal inheritance from sealed class H
+class S extends H {
+                ^
+s.scala:8: error: illegal inheritance from sealed trait I
+trait T extends I {
+                ^
+2 errors

test/files/neg/t12159/H.java

@@ -0,0 +1,19 @@
+// javaVersion: 17+
+package p;
+
+sealed public class H {
+}
+
+final class K extends H {
+}
+
+non-sealed class L extends H {
+}
+
+sealed
+class P extends H {
+}
+
+final
+class Q extends P {
+}

test/files/neg/t12159/I.java

@@ -0,0 +1,6 @@
+// javaVersion: 17+
+
+package p;
+
+sealed interface I permits J {
+}

test/files/neg/t12159/J.java

@@ -0,0 +1,6 @@
+// javaVersion: 17+
+
+package p;
+
+sealed public class J implements I permits M {
+}

test/files/neg/t12159/M.java

@@ -0,0 +1,9 @@
+// javaVersion: 17+
+
+package p;
+
+public final class M extends J {
+}
+
+final class N extends L {
+}

test/files/neg/t12159/s.scala

@@ -0,0 +1,9 @@
+// javaVersion: 17+
+
+package p
+
+class S extends H {
+}
+
+trait T extends I {
+}

test/files/neg/t12159b.check

@@ -0,0 +1,4 @@
+s_2.scala:5: error: illegal inheritance from sealed trait I_1
+class S extends I_1
+                ^
+1 error

test/files/neg/t12159b/I_1.java

@@ -0,0 +1,6 @@
+// javaVersion: 17+
+
+package p;
+
+sealed interface I_1 permits J_1 {
+}

test/files/neg/t12159b/J_1.java

@@ -0,0 +1,6 @@
+// javaVersion: 17+
+
+package p;
+
+public final class J_1 implements I_1 {
+}

test/files/neg/t12159b/s_2.scala

@@ -0,0 +1,8 @@
+// javaVersion: 17+
+// skalac: -Vdebug -Vlog:_
+
+package p
+
+class S extends I_1
+
+//[log typer] trait I_1 is Java sealed.

test/files/pos/t12159/H.java

@@ -0,0 +1,19 @@
+// javaVersion: 17+
+package p;
+
+sealed public class H {
+}
+
+final class K extends H {
+}
+
+non-sealed class L extends H {
+}
+
+sealed
+class P extends H {
+}
+
+final
+class Q extends P {
+}

test/files/pos/t12159/I.java

@@ -0,0 +1,6 @@
+// javaVersion: 17+
+
+package p;
+
+sealed interface I permits J {
+}

test/files/pos/t12159/J.java

@@ -0,0 +1,6 @@
+// javaVersion: 17+
+
+package p;
+
+sealed public class J implements I permits M {
+}

test/files/pos/t12159/M.java

@@ -0,0 +1,9 @@
+// javaVersion: 17+
+
+package p;
+
+public final class M extends J {
+}
+
+final class N extends L {
+}

test/files/pos/t12159/s.scala

@@ -0,0 +1,6 @@
+// javaVersion: 17+
+
+package p
+
+class S extends L {
+}