Add transparent methods

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

@@ -551,6 +551,7 @@ trait TypedTreeInfo extends TreeInfo[Type] { self: Trees.Instance[Type] =>
   /** An extractor for def of a closure contained the block of the closure. */
   object closureDef {
     def unapply(tree: Tree): Option[DefDef] = tree match {
+      case Block(Nil, expr) => unapply(expr)
       case Block((meth @ DefDef(nme.ANON_FUN, _, _, _, _)) :: Nil, closure: Closure) =>
         Some(meth)
       case _ => None

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

@@ -132,6 +132,8 @@ object untpd extends Trees.Instance[Untyped] with UntypedTreeInfo {
 
     case class Inline() extends Mod(Flags.Inline)
 
+    case class Transparent() extends Mod(Flags.Transparent)
+
     case class Enum() extends Mod(Flags.Enum)
   }
 

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

@@ -363,7 +363,10 @@ object Flags {
   /** Symbol is a Java default method */
   final val DefaultMethod = termFlag(38, "<defaultmethod>")
 
-  /** Symbol is a Java enum */
+  /** Labelled with `transparent` modifier */
+  final val Transparent = termFlag(39, "transparent")
+
+  /** Symbol is an enum class or enum case (if used with case) */
   final val Enum = commonFlag(40, "<enum>")
 
   /** Labeled with `erased` modifier (erased value)  */
@@ -436,7 +439,7 @@ object Flags {
 
   /** Flags representing source modifiers */
   final val SourceModifierFlags =
-    commonFlags(Private, Protected, Abstract, Final, Inline,
+    commonFlags(Private, Protected, Abstract, Final, Inline, Transparent,
      Sealed, Case, Implicit, Override, AbsOverride, Lazy, JavaStatic, Erased)
 
   /** Flags representing modifiers that can appear in trees */
@@ -457,7 +460,7 @@ object Flags {
     Scala2ExistentialCommon | Mutable.toCommonFlags | Touched | JavaStatic |
     CovariantOrOuter | ContravariantOrLabel | CaseAccessor.toCommonFlags |
     NonMember | ImplicitCommon | Permanent | Synthetic |
-    SuperAccessorOrScala2x | Inline
+    SuperAccessorOrScala2x | Inline | Transparent.toCommonFlags
 
   /** Flags that are not (re)set when completing the denotation, or, if symbol is
    *  a top-level class or object, when completing the denotation once the class
@@ -513,7 +516,7 @@ object Flags {
   /** Flags that can apply to a module val */
   final val RetainedModuleValFlags: FlagSet = RetainedModuleValAndClassFlags |
     Override | Final | Method | Implicit | Lazy |
-    Accessor | AbsOverride | Stable | Captured | Synchronized | Inline | Erased
+    Accessor | AbsOverride | Stable | Captured | Synchronized | Erased
 
   /** Flags that can apply to a module class */
   final val RetainedModuleClassFlags: FlagSet = RetainedModuleValAndClassFlags | ImplClass | Enum
@@ -548,8 +551,8 @@ object Flags {
   /** Either method or lazy or deferred */
   final val MethodOrLazyOrDeferred = Method | Lazy | Deferred
 
-  /** Labeled `private`, `final`, or `inline` */
-  final val PrivateOrFinalOrInline = Private | Final | Inline
+  /** Labeled `private`, `final`, `inline`, or `transparent` */
+  final val EffectivelyFinal = Private | Final | Inline | Transparent.toCommonFlags
 
   /** A private method */
   final val PrivateMethod = allOf(Private, Method)
@@ -560,6 +563,9 @@ object Flags {
   /** An inline method */
   final val InlineMethod = allOf(Inline, Method)
 
+  /** An transparent method */
+  final val TransparentMethod = allOf(Transparent, Method)
+
   /** An inline parameter */
   final val InlineParam = allOf(Inline, Param)
 
@@ -575,6 +581,9 @@ object Flags {
   /** An accessor or label */
   final val AccessorOrLabel = Accessor | Label
 
+  /** An accessor or a synthetic symbol */
+  final val AccessorOrSynthetic = Accessor | Synthetic
+
   /** A synthetic or private definition */
   final val SyntheticOrPrivate = Synthetic | Private
 
@@ -584,8 +593,8 @@ object Flags {
   /** A deferred type member or parameter (these don't have right hand sides) */
   final val DeferredOrTypeParam = Deferred | TypeParam
 
-  /** value that's final or inline */
-  final val FinalOrInline = Final | Inline
+  /** value that's final, inline, or transparent */
+  final val FinalOrInlineOrTransparent = Final | Inline | Transparent.toCommonFlags
 
   /** A covariant type parameter instance */
   final val LocalCovariant = allOf(Local, Covariant)

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

@@ -93,5 +93,4 @@ object Mode {
 
   /** We are in the IDE */
   val Interactive = newMode(20, "Interactive")
-
 }

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

@@ -779,7 +779,13 @@ object SymDenotations {
 
     def isSkolem: Boolean = name == nme.SKOLEM
 
-    def isInlineMethod(implicit ctx: Context): Boolean = is(InlineMethod, butNot = Accessor)
+    def isInlinedMethod(implicit ctx: Context): Boolean =
+      is(InlineMethod, butNot = Accessor)
+
+    def isTransparentMethod(implicit ctx: Context): Boolean =
+      is(TransparentMethod, butNot = Accessor)
+
+    def isInlineableMethod(implicit ctx: Context) = isInlinedMethod || isTransparentMethod
 
     /** ()T and => T types should be treated as equivalent for this symbol.
      *  Note: For the moment, we treat Scala-2 compiled symbols as loose matching,
@@ -905,7 +911,7 @@ object SymDenotations {
 
     /** A symbol is effectively final if it cannot be overridden in a subclass */
     final def isEffectivelyFinal(implicit ctx: Context): Boolean =
-      is(PrivateOrFinalOrInline) || !owner.isClass || owner.is(ModuleOrFinal) || owner.isAnonymousClass
+      is(EffectivelyFinal) || !owner.isClass || owner.is(ModuleOrFinal) || owner.isAnonymousClass
 
     /** The class containing this denotation which has the given effective name. */
     final def enclosingClassNamed(name: Name)(implicit ctx: Context): Symbol = {

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

@@ -179,7 +179,8 @@ Standard-Section: "ASTs" TopLevelStat*
                   ERASED
                   LAZY
                   OVERRIDE
-                  INLINE                              // inline method
+                  INLINE
+                  TRANSPARENT
                   MACRO                               // inline method containing toplevel splices
                   STATIC                              // mapped to static Java member
                   OBJECT                              // an object or its class
@@ -280,25 +281,26 @@ object TastyFormat {
   final val LAZY = 14
   final val OVERRIDE = 15
   final val INLINE = 16
-  final val STATIC = 17
-  final val OBJECT = 18
-  final val TRAIT = 19
-  final val ENUM = 20
-  final val LOCAL = 21
-  final val SYNTHETIC = 22
-  final val ARTIFACT = 23
-  final val MUTABLE = 24
-  final val LABEL = 25
-  final val FIELDaccessor = 26
-  final val CASEaccessor = 27
-  final val COVARIANT = 28
-  final val CONTRAVARIANT = 29
-  final val SCALA2X = 30
-  final val DEFAULTparameterized = 31
-  final val STABLE = 32
-  final val MACRO = 33
-  final val ERASED = 34
-  final val PARAMsetter = 35
+  final val TRANSPARENT = 17
+  final val STATIC = 18
+  final val OBJECT = 19
+  final val TRAIT = 20
+  final val ENUM = 21
+  final val LOCAL = 22
+  final val SYNTHETIC = 23
+  final val ARTIFACT = 24
+  final val MUTABLE = 25
+  final val LABEL = 26
+  final val FIELDaccessor = 27
+  final val CASEaccessor = 28
+  final val COVARIANT = 29
+  final val CONTRAVARIANT = 30
+  final val SCALA2X = 31
+  final val DEFAULTparameterized = 32
+  final val STABLE = 33
+  final val MACRO = 34
+  final val ERASED = 35
+  final val PARAMsetter = 36
 
   // Cat. 2:    tag Nat
 
@@ -446,6 +448,7 @@ object TastyFormat {
        | LAZY
        | OVERRIDE
        | INLINE
+       | TRANSPARENT
        | MACRO
        | STATIC
        | OBJECT
@@ -502,6 +505,7 @@ object TastyFormat {
     case LAZY => "LAZY"
     case OVERRIDE => "OVERRIDE"
     case INLINE => "INLINE"
+    case TRANSPARENT => "TRANSPARENT"
     case MACRO => "MACRO"
     case STATIC => "STATIC"
     case OBJECT => "OBJECT"

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

@@ -589,6 +589,7 @@ class TreePickler(pickler: TastyPickler) {
     if (flags is Case) writeByte(CASE)
     if (flags is Override) writeByte(OVERRIDE)
     if (flags is Inline) writeByte(INLINE)
+    if (flags is Transparent) writeByte(TRANSPARENT)
     if (flags is Macro) writeByte(MACRO)
     if (flags is JavaStatic) writeByte(STATIC)
     if (flags is Module) writeByte(OBJECT)

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

@@ -513,7 +513,7 @@ class TreeUnpickler(reader: TastyReader,
       val rhsStart = currentAddr
       val rhsIsEmpty = nothingButMods(end)
       if (!rhsIsEmpty) skipTree()
-      val (givenFlags, annots, privateWithin) = readModifiers(end)
+      val (givenFlags, annotFns, privateWithin) = readModifiers(end)
       pickling.println(i"creating symbol $name at $start with flags $givenFlags")
       val flags = normalizeFlags(tag, givenFlags, name, isAbsType, rhsIsEmpty)
       def adjustIfModule(completer: LazyType) =
@@ -532,13 +532,12 @@ class TreeUnpickler(reader: TastyReader,
             rootd.symbol
           case _ =>
             val completer = adjustIfModule(new Completer(ctx.owner, subReader(start, end)))
-
             if (isClass)
               ctx.newClassSymbol(ctx.owner, name.asTypeName, flags, completer, privateWithin, coord)
             else
               ctx.newSymbol(ctx.owner, name, flags, completer, privateWithin, coord)
         }
-      sym.annotations = annots
+      sym.annotations = annotFns.map(_(sym))
       ctx.owner match {
         case cls: ClassSymbol => cls.enter(sym)
         case _ =>
@@ -548,7 +547,7 @@ class TreeUnpickler(reader: TastyReader,
         sym.completer.withDecls(newScope)
         forkAt(templateStart).indexTemplateParams()(localContext(sym))
       }
-      else if (sym.isInlineMethod)
+      else if (sym.isInlineableMethod)
         sym.addAnnotation(LazyBodyAnnotation { ctx0 =>
           implicit val ctx: Context = localContext(sym)(ctx0).addMode(Mode.ReadPositions)
             // avoids space leaks by not capturing the current context
@@ -561,9 +560,9 @@ class TreeUnpickler(reader: TastyReader,
     /** Read modifier list into triplet of flags, annotations and a privateWithin
      *  boundary symbol.
      */
-    def readModifiers(end: Addr)(implicit ctx: Context): (FlagSet, List[Annotation], Symbol) = {
+    def readModifiers(end: Addr)(implicit ctx: Context): (FlagSet, List[Symbol => Annotation], Symbol) = {
       var flags: FlagSet = EmptyFlags
-      var annots: List[Annotation] = Nil
+      var annotFns: List[Symbol => Annotation] = Nil
       var privateWithin: Symbol = NoSymbol
       while (currentAddr.index != end.index) {
         def addFlag(flag: FlagSet) = {
@@ -588,6 +587,7 @@ class TreeUnpickler(reader: TastyReader,
           case LAZY => addFlag(Lazy)
           case OVERRIDE => addFlag(Override)
           case INLINE => addFlag(Inline)
+          case TRANSPARENT => addFlag(Transparent)
           case MACRO => addFlag(Macro)
           case STATIC => addFlag(JavaStatic)
           case OBJECT => addFlag(Module)
@@ -614,23 +614,25 @@ class TreeUnpickler(reader: TastyReader,
             addFlag(Protected)
             privateWithin = readType().typeSymbol
           case ANNOTATION =>
-            annots = readAnnot(ctx) :: annots
+            annotFns = readAnnot(ctx) :: annotFns
           case tag =>
             assert(false, s"illegal modifier tag $tag at $currentAddr, end = $end")
         }
       }
-      (flags, annots.reverse, privateWithin)
+      (flags, annotFns.reverse, privateWithin)
     }
 
-    private val readAnnot: Context => Annotation = {
+    private val readAnnot: Context => Symbol => Annotation = {
       implicit ctx =>
         readByte()
         val end = readEnd()
         val tp = readType()
-        val lazyAnnotTree = readLater(end, rdr => ctx => rdr.readTerm()(ctx))
-        Annotation.deferredSymAndTree(
-          implicit ctx => tp.typeSymbol,
-          implicit ctx => lazyAnnotTree.complete)
+        val lazyAnnotTree = readLaterWithOwner(end, rdr => ctx => rdr.readTerm()(ctx))
+
+        owner =>
+          Annotation.deferredSymAndTree(
+            implicit ctx => tp.typeSymbol,
+            implicit ctx => lazyAnnotTree(owner).complete)
     }
 
     /** Create symbols for the definitions in the statement sequence between
@@ -1153,10 +1155,13 @@ class TreeUnpickler(reader: TastyReader,
       setPos(start, CaseDef(pat, guard, rhs))
     }
 
-    def readLater[T <: AnyRef](end: Addr, op: TreeReader => Context => T)(implicit ctx: Context): Trees.Lazy[T] = {
+    def readLater[T <: AnyRef](end: Addr, op: TreeReader => Context => T)(implicit ctx: Context): Trees.Lazy[T] =
+      readLaterWithOwner(end, op)(ctx)(ctx.owner)
+
+    def readLaterWithOwner[T <: AnyRef](end: Addr, op: TreeReader => Context => T)(implicit ctx: Context): Symbol => Trees.Lazy[T] = {
       val localReader = fork
       goto(end)
-      new LazyReader(localReader, ctx.owner, ctx.mode, op)
+      owner => new LazyReader(localReader, owner, ctx.mode, op)
     }
 
     def readHole(end: Addr, isType: Boolean)(implicit ctx: Context): Tree = {

compiler/src/dotty/tools/dotc/parsing/Parsers.scala

@@ -1675,16 +1675,17 @@ object Parsers {
 /* -------- MODIFIERS and ANNOTATIONS ------------------------------------------- */
 
     private def modOfToken(tok: Int): Mod = tok match {
-      case ABSTRACT  => Mod.Abstract()
-      case FINAL     => Mod.Final()
-      case IMPLICIT  => Mod.Implicit()
-      case ERASED    => Mod.Erased()
-      case INLINE    => Mod.Inline()
-      case LAZY      => Mod.Lazy()
-      case OVERRIDE  => Mod.Override()
-      case PRIVATE   => Mod.Private()
-      case PROTECTED => Mod.Protected()
-      case SEALED    => Mod.Sealed()
+      case ABSTRACT    => Mod.Abstract()
+      case FINAL       => Mod.Final()
+      case IMPLICIT    => Mod.Implicit()
+      case ERASED      => Mod.Erased()
+      case INLINE      => Mod.Inline()
+      case TRANSPARENT => Mod.Transparent()
+      case LAZY        => Mod.Lazy()
+      case OVERRIDE    => Mod.Override()
+      case PRIVATE     => Mod.Private()
+      case PROTECTED   => Mod.Protected()
+      case SEALED      => Mod.Sealed()
     }
 
     /** Drop `private' modifier when followed by a qualifier.

compiler/src/dotty/tools/dotc/parsing/Tokens.scala

@@ -176,8 +176,9 @@ object Tokens extends TokensCommon {
   final val THEN = 60;             enter(THEN, "then")
   final val FORSOME = 61;          enter(FORSOME, "forSome") // TODO: deprecate
   final val INLINE = 62;           enter(INLINE, "inline")
-  final val ENUM = 63;             enter(ENUM, "enum")
-  final val ERASED = 64;           enter(ERASED, "erased")
+  final val TRANSPARENT = 63;      enter(TRANSPARENT, "transparent")
+  final val ENUM = 64;             enter(ENUM, "enum")
+  final val ERASED = 65;           enter(ERASED, "erased")
 
   /** special symbols */
   final val NEWLINE = 78;          enter(NEWLINE, "end of statement", "new line")
@@ -226,7 +227,7 @@ object Tokens extends TokensCommon {
   final val defIntroTokens = templateIntroTokens | dclIntroTokens
 
   final val localModifierTokens = BitSet(
-    ABSTRACT, FINAL, SEALED, IMPLICIT, INLINE, LAZY, ERASED)
+    ABSTRACT, FINAL, SEALED, IMPLICIT, INLINE, TRANSPARENT, LAZY, ERASED)
 
   final val accessModifierTokens = BitSet(
     PRIVATE, PROTECTED)

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

@@ -612,7 +612,7 @@ class RefinedPrinter(_ctx: Context) extends PlainPrinter(_ctx) {
   }
 
   private def toTextOwner(tree: Tree[_]) =
-    "[owner = " ~ tree.symbol.owner.show ~ "]" provided ctx.settings.YprintDebugOwners.value
+    "[owner = " ~ tree.symbol.maybeOwner.show ~ "]" provided ctx.settings.YprintDebugOwners.value
 
   protected def dclTextOr[T >: Untyped](tree: Tree[T])(treeText: => Text) =
     toTextOwner(tree) ~ {

compiler/src/dotty/tools/dotc/reporting/diagnostic/messages.scala

@@ -1575,7 +1575,7 @@ object messages {
     private val varNote =
       if (sym.is(Mutable)) "Note that variables need to be initialized to be defined."
       else ""
-    val msg = hl"""only classes can have declared but undefined members"""
+    val msg = hl"""declaration of $sym not allowed here: only classes can have declared but undefined members"""
     val kind = "Syntax"
     val explanation = s"$varNote"
   }

compiler/src/dotty/tools/dotc/transform/PostTyper.scala

@@ -165,7 +165,7 @@ class PostTyper extends MacroTransform with IdentityDenotTransformer { thisPhase
 
       def markAsMacro(c: Context): Unit =
         if (c.owner eq c.outer.owner) markAsMacro(c.outer)
-        else if (c.owner.isInlineMethod) c.owner.setFlag(Macro)
+        else if (c.owner.isInlineableMethod) c.owner.setFlag(Macro)
         else if (!c.outer.owner.is(Package)) markAsMacro(c.outer)
 
       if (sym.isSplice || sym.isQuote) {
@@ -192,10 +192,6 @@ class PostTyper extends MacroTransform with IdentityDenotTransformer { thisPhase
           }
           else
             transformSelect(tree, Nil)
-        case tree: Super =>
-          if (ctx.owner.enclosingMethod.isInlineMethod)
-            ctx.error(SuperCallsNotAllowedInline(ctx.owner), tree.pos)
-          super.transform(tree)
         case tree: Apply =>
           methPart(tree) match {
             case Select(nu: New, nme.CONSTRUCTOR) if isCheckable(nu) =>