Merge pull request #9930 from dotty-staging/remove-enum-constant

Author: smarter

compiler/src/dotty/tools/backend/jvm/BCodeBodyBuilder.scala

@@ -488,7 +488,7 @@ trait BCodeBodyBuilder extends BCodeSkelBuilder {
     // ---------------- emitting constant values ----------------
 
     /*
-     * For const.tag in {ClazzTag, EnumTag}
+     * For ClazzTag:
      *   must-single-thread
      * Otherwise it's safe to call from multiple threads.
      */
@@ -527,22 +527,6 @@ trait BCodeBodyBuilder extends BCodeSkelBuilder {
           else
             mnode.visitLdcInsn(tp.toASMType)
 
-        case EnumTag   =>
-          val sym       = const.symbolValue
-          val ownerName = internalName(sym.owner)
-          val fieldName = sym.javaSimpleName
-          val underlying = sym.info match { // TODO: Is this actually necessary? Could it be replaced by a call to widen?
-            case t: TypeProxy => t.underlying
-            case t => t
-          }
-          val fieldDesc = toTypeKind(underlying).descriptor
-          mnode.visitFieldInsn(
-            asm.Opcodes.GETSTATIC,
-            ownerName,
-            fieldName,
-            fieldDesc
-          )
-
         case _ => abort(s"Unknown constant value: $const")
       }
     }

compiler/src/dotty/tools/backend/jvm/BCodeHelpers.scala

@@ -377,14 +377,10 @@ trait BCodeHelpers extends BCodeIdiomatic with BytecodeWriters {
               assert(const.value != null, const) // TODO this invariant isn't documented in `case class Constant`
               av.visit(name, const.stringValue) // `stringValue` special-cases null, but that execution path isn't exercised for a const with StringTag
             case ClazzTag => av.visit(name, typeToTypeKind(TypeErasure.erasure(const.typeValue))(bcodeStore)(innerClasesStore).toASMType)
-            case EnumTag =>
-              val edesc = innerClasesStore.typeDescriptor(const.tpe) // the class descriptor of the enumeration class.
-              val evalue = const.symbolValue.javaSimpleName // value the actual enumeration value.
-              av.visitEnum(name, edesc, evalue)
           }
         case Ident(nme.WILDCARD) =>
           // An underscore argument indicates that we want to use the default value for this parameter, so do not emit anything
-        case t: tpd.RefTree if t.symbol.denot.owner.isAllOf(JavaEnumTrait) =>
+        case t: tpd.RefTree if t.symbol.owner.linkedClass.isAllOf(JavaEnumTrait) =>
           val edesc = innerClasesStore.typeDescriptor(t.tpe) // the class descriptor of the enumeration class.
           val evalue = t.symbol.javaSimpleName // value the actual enumeration value.
           av.visitEnum(name, edesc, evalue)
@@ -454,7 +450,7 @@ trait BCodeHelpers extends BCodeIdiomatic with BytecodeWriters {
 
     private def retentionPolicyOf(annot: Annotation): Symbol =
       annot.tree.tpe.typeSymbol.getAnnotation(AnnotationRetentionAttr).
-        flatMap(_.argumentConstant(0).map(_.symbolValue)).getOrElse(AnnotationRetentionClassAttr)
+        flatMap(_.argument(0).map(_.tpe.termSymbol)).getOrElse(AnnotationRetentionClassAttr)
 
     private def assocsFromApply(tree: Tree): List[(Name, Tree)] = {
       tree match {

compiler/src/dotty/tools/backend/sjs/JSCodeGen.scala

@@ -1420,8 +1420,6 @@ class JSCodeGen()(using genCtx: Context) {
             js.Null()
           case ClazzTag =>
             genClassConstant(value.typeValue)
-          case EnumTag =>
-            genLoadStaticField(value.symbolValue)
         }
 
       case Block(stats, expr) =>

compiler/src/dotty/tools/dotc/ast/untpd.scala

@@ -460,6 +460,9 @@ object untpd extends Trees.Instance[Untyped] with UntypedTreeInfo {
   def ref(tp: NamedType)(using Context): Tree =
     TypedSplice(tpd.ref(tp))
 
+  def ref(sym: Symbol)(using Context): Tree =
+    TypedSplice(tpd.ref(sym))
+
   def rawRef(tp: NamedType)(using Context): Tree =
     if tp.typeParams.isEmpty then ref(tp)
     else AppliedTypeTree(ref(tp), tp.typeParams.map(_ => WildcardTypeBoundsTree()))

compiler/src/dotty/tools/dotc/core/Constants.scala

@@ -20,8 +20,6 @@ object Constants {
   final val StringTag  = 10
   final val NullTag    = 11
   final val ClazzTag   = 12
-  // For supporting java enumerations inside java annotations (see ClassfileParser)
-  final val EnumTag    = 13
 
   class Constant(val value: Any, val tag: Int) extends printing.Showable with Product1[Any] {
     import java.lang.Double.doubleToRawLongBits
@@ -50,7 +48,6 @@ object Constants {
       case StringTag      => defn.StringType
       case NullTag        => defn.NullType
       case ClazzTag       => defn.ClassType(typeValue)
-      case EnumTag        => defn.EnumType(symbolValue)
     }
 
     /** We need the equals method to take account of tags as well as values.
@@ -190,7 +187,6 @@ object Constants {
     def toText(printer: Printer): Text = printer.toText(this)
 
     def typeValue: Type     = value.asInstanceOf[Type]
-    def symbolValue: Symbol = value.asInstanceOf[Symbol]
 
     /**
      * Consider two `NaN`s to be identical, despite non-equality
@@ -237,7 +233,6 @@ object Constants {
     def apply(x: String): Constant       = new Constant(x, StringTag)
     def apply(x: Char): Constant         = new Constant(x, CharTag)
     def apply(x: Type): Constant         = new Constant(x, ClazzTag)
-    def apply(x: Symbol): Constant       = new Constant(x, EnumTag)
     def apply(value: Any): Constant      =
       new Constant(value,
         value match {
@@ -253,7 +248,6 @@ object Constants {
           case x: String       => StringTag
           case x: Char         => CharTag
           case x: Type         => ClazzTag
-          case x: Symbol       => EnumTag
         }
       )
 

compiler/src/dotty/tools/dotc/core/classfile/ClassfileParser.scala

@@ -282,7 +282,6 @@ class ClassfileParser(
 
         val isVarargs = denot.is(Flags.Method) && (jflags & JAVA_ACC_VARARGS) != 0
         denot.info = pool.getType(in.nextChar, isVarargs)
-        if (isEnum) denot.info = ConstantType(Constant(sym))
         if (isConstructor) normalizeConstructorParams()
         denot.info = translateTempPoly(parseAttributes(sym, denot.info, isVarargs))
         if (isConstructor) normalizeConstructorInfo()
@@ -525,17 +524,13 @@ class ClassfileParser(
       case CLASS_TAG =>
         if (skip) None else Some(lit(Constant(pool.getType(index))))
       case ENUM_TAG =>
-        val t = pool.getType(index)
-        val n = pool.getName(in.nextChar)
-        val module = t.typeSymbol.companionModule
-        val s = module.info.decls.lookup(n)
+        val enumClassTp = pool.getType(index)
+        val enumCaseName = pool.getName(in.nextChar)
         if (skip)
           None
-        else if (s != NoSymbol)
-          Some(lit(Constant(s)))
         else {
-          report.warning(s"""While parsing annotations in ${in.file}, could not find $n in enum $module.\nThis is likely due to an implementation restriction: an annotation argument cannot refer to a member of the annotated class (SI-7014).""")
-          None
+          val enumModuleClass = enumClassTp.classSymbol.companionModule
+          Some(Select(ref(enumModuleClass), enumCaseName))
         }
       case ARRAY_TAG =>
         val arr = new ArrayBuffer[Tree]()

compiler/src/dotty/tools/dotc/core/tasty/TreePickler.scala

@@ -152,9 +152,6 @@ class TreePickler(pickler: TastyPickler) {
     case ClazzTag =>
       writeByte(CLASSconst)
       pickleType(c.typeValue)
-    case EnumTag =>
-      writeByte(ENUMconst)
-      pickleType(c.symbolValue.termRef)
   }
 
   def pickleVariances(tp: Type)(using Context): Unit = tp match

compiler/src/dotty/tools/dotc/core/tasty/TreeUnpickler.scala

@@ -286,8 +286,6 @@ class TreeUnpickler(reader: TastyReader,
         Constant(null)
       case CLASSconst =>
         Constant(readType())
-      case ENUMconst =>
-        Constant(readTermRef().termSymbol)
     }
 
     /** Read a type */

compiler/src/dotty/tools/dotc/core/unpickleScala2/Scala2Unpickler.scala

@@ -735,7 +735,9 @@ class Scala2Unpickler(bytes: Array[Byte], classRoot: ClassDenotation, moduleClas
         val supertpe = readTypeRef()
         SuperType(thistpe, supertpe)
       case CONSTANTtpe =>
-        ConstantType(readConstantRef())
+        readConstantRef() match
+          case c: Constant => ConstantType(c)
+          case tp: TermRef => tp
       case TYPEREFtpe =>
         var pre = readPrefix()
         val sym = readSymbolRef()
@@ -822,7 +824,7 @@ class Scala2Unpickler(bytes: Array[Byte], classRoot: ClassDenotation, moduleClas
     errorBadSignature("bad type tag: " + tag)
 
   /** Read a constant */
-  protected def readConstant()(using Context): Constant = {
+  protected def readConstant()(using Context): Constant | TermRef = {
     val tag = readByte().toInt
     val len = readNat()
     (tag: @switch) match {
@@ -838,7 +840,7 @@ class Scala2Unpickler(bytes: Array[Byte], classRoot: ClassDenotation, moduleClas
       case LITERALstring => Constant(readNameRef().toString)
       case LITERALnull => Constant(null)
       case LITERALclass => Constant(readTypeRef())
-      case LITERALenum => Constant(readSymbolRef())
+      case LITERALenum => readSymbolRef().termRef
       case _ => noSuchConstantTag(tag, len)
     }
   }
@@ -881,7 +883,7 @@ class Scala2Unpickler(bytes: Array[Byte], classRoot: ClassDenotation, moduleClas
 
   protected def readNameRef()(using Context): Name = at(readNat(), () => readName())
   protected def readTypeRef()(using Context): Type = at(readNat(), () => readType()) // after the NMT_TRANSITION period, we can leave off the () => ... ()
-  protected def readConstantRef()(using Context): Constant = at(readNat(), () => readConstant())
+  protected def readConstantRef()(using Context): Constant | TermRef = at(readNat(), () => readConstant())
 
   protected def readTypeNameRef()(using Context): TypeName = readNameRef().toTypeName
   protected def readTermNameRef()(using Context): TermName = readNameRef().toTermName
@@ -896,7 +898,11 @@ class Scala2Unpickler(bytes: Array[Byte], classRoot: ClassDenotation, moduleClas
    */
   protected def readAnnotArg(i: Int)(using Context): Tree = bytes(index(i)) match {
     case TREE => at(i, () => readTree())
-    case _ => Literal(at(i, () => readConstant()))
+    case _ => at(i, () =>
+      readConstant() match
+        case c: Constant => Literal(c)
+        case tp: TermRef => ref(tp)
+    )
   }
 
   /** Read a ClassfileAnnotArg (argument to a classfile annotation)
@@ -1208,7 +1214,9 @@ class Scala2Unpickler(bytes: Array[Byte], classRoot: ClassDenotation, moduleClas
         Ident(symbol.namedType)
 
       case LITERALtree =>
-        Literal(readConstantRef())
+        readConstantRef() match
+          case c: Constant => Literal(c)
+          case tp: TermRef => ref(tp)
 
       case TYPEtree =>
         TypeTree(tpe)

compiler/src/dotty/tools/dotc/printing/PlainPrinter.scala

@@ -528,7 +528,6 @@ class PlainPrinter(_ctx: Context) extends Printer {
     case ClazzTag => "classOf[" ~ toText(const.typeValue) ~ "]"
     case CharTag => literalText(s"'${escapedChar(const.charValue)}'")
     case LongTag => literalText(const.longValue.toString + "L")
-    case EnumTag => literalText(const.symbolValue.name.toString)
     case _ => literalText(String.valueOf(const.value))
   }