Merge pull request #6910 from dotty-staging/refactor-delegate-flags

Refactor Delegate flags

Author: odersky

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

@@ -480,7 +480,7 @@ object desugar {
         if (enumCases.isEmpty)
           ctx.error("Enumerations must constain at least one case", namePos)
         val enumCompanionRef = TermRefTree()
-        val enumImport = Import(importDelegate = false, enumCompanionRef, enumCases.flatMap(caseIds))
+        val enumImport = Import(importGiven = false, enumCompanionRef, enumCases.flatMap(caseIds))
         (enumImport :: enumStats, enumCases, enumCompanionRef)
       }
       else (stats, Nil, EmptyTree)
@@ -750,7 +750,7 @@ object desugar {
     //     synthetic implicit C[Ts](p11: T11, ..., p1N: T1N) ... (pM1: TM1, ..., pMN: TMN): C[Ts] =
     //       new C[Ts](p11, ..., p1N) ... (pM1, ..., pMN) =
     val implicitWrappers =
-      if (!mods.isOneOf(DelegateOrImplicit))
+      if (!mods.isOneOf(GivenOrImplicit))
         Nil
       else if (ctx.owner.is(Package)) {
         ctx.error(TopLevelImplicitClass(cdef), cdef.sourcePos)
@@ -764,7 +764,7 @@ object desugar {
         ctx.error(ImplicitCaseClass(cdef), cdef.sourcePos)
         Nil
       }
-      else if (arity != 1 && !mods.is(Delegate)) {
+      else if (arity != 1 && !mods.is(Given)) {
         ctx.error(ImplicitClassPrimaryConstructorArity(), cdef.sourcePos)
         Nil
       }
@@ -778,7 +778,7 @@ object desugar {
         // implicit wrapper is typechecked in same scope as constructor, so
         // we can reuse the constructor parameters; no derived params are needed.
         DefDef(className.toTermName, constrTparams, defParamss, classTypeRef, creatorExpr)
-          .withMods(companionMods | mods.flags.toTermFlags & DelegateOrImplicit | Synthetic | Final)
+          .withMods(companionMods | mods.flags.toTermFlags & GivenOrImplicit | Synthetic | Final)
           .withSpan(cdef.span) :: Nil
       }
 
@@ -1177,14 +1177,14 @@ object desugar {
    */
   def packageDef(pdef: PackageDef)(implicit ctx: Context): PackageDef = {
     def isWrappedType(stat: TypeDef): Boolean =
-      !stat.isClassDef || stat.mods.isOneOf(DelegateOrImplicit)
+      !stat.isClassDef || stat.mods.isOneOf(GivenOrImplicit)
     val wrappedTypeNames = pdef.stats.collect {
       case stat: TypeDef if isWrappedType(stat) => stat.name
     }
     def needsObject(stat: Tree) = stat match {
       case _: ValDef | _: PatDef | _: DefDef | _: Export => true
       case stat: ModuleDef =>
-        stat.mods.isOneOf(DelegateOrImplicit) ||
+        stat.mods.isOneOf(GivenOrImplicit) ||
         wrappedTypeNames.contains(stat.name.stripModuleClassSuffix.toTypeName)
       case stat: TypeDef => isWrappedType(stat)
       case _ => false

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

@@ -874,7 +874,7 @@ object TreeInfo {
   /** The expression has no side effects */
   val Pure: PurityLevel = new PurityLevel(3)
 
-  /** Running the expression a second time has no side effects. Delegate by `Pure`. */
+  /** Running the expression a second time has no side effects. Implied by `Pure`. */
   val Idempotent: PurityLevel = new PurityLevel(1)
 
   val Impure: PurityLevel = new PurityLevel(0)

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

@@ -754,7 +754,7 @@ object Trees {
     def unforced: LazyTree[T] = preRhs
     protected def force(x: Tree[T @uncheckedVariance]): Unit = preRhs = x
 
-    override def disableOverlapChecks = rawMods.is(Delegate)
+    override def disableOverlapChecks = rawMods.is(Given)
       // disable order checks for implicit aliases since their given clause follows
       // their for clause, but the two appear swapped in the DefDef.
   }
@@ -800,7 +800,7 @@ object Trees {
    *  where a selector is either an untyped `Ident`, `name` or
    *  an untyped thicket consisting of `name` and `rename`.
    */
-  case class Import[-T >: Untyped] private[ast] (importDelegate: Boolean, expr: Tree[T], selectors: List[Tree[Untyped]])(implicit @constructorOnly src: SourceFile)
+  case class Import[-T >: Untyped] private[ast] (importGiven: Boolean, expr: Tree[T], selectors: List[Tree[Untyped]])(implicit @constructorOnly src: SourceFile)
     extends DenotingTree[T] {
     type ThisTree[-T >: Untyped] = Import[T]
   }
@@ -1188,9 +1188,9 @@ object Trees {
         case tree: Template if (constr eq tree.constr) && (parents eq tree.parents) && (derived eq tree.derived) && (self eq tree.self) && (body eq tree.unforcedBody) => tree
         case tree => finalize(tree, untpd.Template(constr, parents, derived, self, body)(sourceFile(tree)))
       }
-      def Import(tree: Tree)(importDelegate: Boolean, expr: Tree, selectors: List[untpd.Tree])(implicit ctx: Context): Import = tree match {
-        case tree: Import if (importDelegate == tree.importDelegate) && (expr eq tree.expr) && (selectors eq tree.selectors) => tree
-        case _ => finalize(tree, untpd.Import(importDelegate, expr, selectors)(sourceFile(tree)))
+      def Import(tree: Tree)(importGiven: Boolean, expr: Tree, selectors: List[untpd.Tree])(implicit ctx: Context): Import = tree match {
+        case tree: Import if (importGiven == tree.importGiven) && (expr eq tree.expr) && (selectors eq tree.selectors) => tree
+        case _ => finalize(tree, untpd.Import(importGiven, expr, selectors)(sourceFile(tree)))
       }
       def PackageDef(tree: Tree)(pid: RefTree, stats: List[Tree])(implicit ctx: Context): PackageDef = tree match {
         case tree: PackageDef if (pid eq tree.pid) && (stats eq tree.stats) => tree
@@ -1331,8 +1331,8 @@ object Trees {
               cpy.TypeDef(tree)(name, transform(rhs))
             case tree @ Template(constr, parents, self, _) if tree.derived.isEmpty =>
               cpy.Template(tree)(transformSub(constr), transform(tree.parents), Nil, transformSub(self), transformStats(tree.body))
-            case Import(importDelegate, expr, selectors) =>
-              cpy.Import(tree)(importDelegate, transform(expr), selectors)
+            case Import(importGiven, expr, selectors) =>
+              cpy.Import(tree)(importGiven, transform(expr), selectors)
             case PackageDef(pid, stats) =>
               cpy.PackageDef(tree)(transformSub(pid), transformStats(stats)(localCtx))
             case Annotated(arg, annot) =>

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

@@ -333,8 +333,8 @@ object tpd extends Trees.Instance[Type] with TypedTreeInfo {
     Block(cdef :: Nil, New(cls.typeRef, Nil))
   }
 
-  def Import(importDelegate: Boolean, expr: Tree, selectors: List[untpd.Tree])(implicit ctx: Context): Import =
-    ta.assignType(untpd.Import(importDelegate, expr, selectors), ctx.newImportSymbol(ctx.owner, expr))
+  def Import(importGiven: Boolean, expr: Tree, selectors: List[untpd.Tree])(implicit ctx: Context): Import =
+    ta.assignType(untpd.Import(importGiven, expr, selectors), ctx.newImportSymbol(ctx.owner, expr))
 
   def PackageDef(pid: RefTree, stats: List[Tree])(implicit ctx: Context): PackageDef =
     ta.assignType(untpd.PackageDef(pid, stats), pid)

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

@@ -165,8 +165,6 @@ object untpd extends Trees.Instance[Untyped] with UntypedTreeInfo {
     case class Lazy()(implicit @constructorOnly src: SourceFile) extends Mod(Flags.Lazy)
 
     case class Inline()(implicit @constructorOnly src: SourceFile) extends Mod(Flags.Inline)
-
-    case class Delegate()(implicit @constructorOnly src: SourceFile) extends Mod(Flags.Delegate)
   }
 
   /** Modifiers and annotations for definitions
@@ -341,7 +339,7 @@ object untpd extends Trees.Instance[Untyped] with UntypedTreeInfo {
   def Template(constr: DefDef, parents: List[Tree], derived: List[Tree], self: ValDef, body: LazyTreeList)(implicit src: SourceFile): Template =
     if (derived.isEmpty) new Template(constr, parents, self, body)
     else new DerivingTemplate(constr, parents ++ derived, self, body, derived.length)
-  def Import(importDelegate: Boolean, expr: Tree, selectors: List[Tree])(implicit src: SourceFile): Import = new Import(importDelegate, expr, selectors)
+  def Import(importGiven: Boolean, expr: Tree, selectors: List[Tree])(implicit src: SourceFile): Import = new Import(importGiven, expr, selectors)
   def PackageDef(pid: RefTree, stats: List[Tree])(implicit src: SourceFile): PackageDef = new PackageDef(pid, stats)
   def Annotated(arg: Tree, annot: Tree)(implicit src: SourceFile): Annotated = new Annotated(arg, annot)
 

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

@@ -13,7 +13,7 @@ import Scopes._
 import Uniques._
 import ast.Trees._
 import ast.untpd
-import Flags.DelegateOrGivenOrImplicit
+import Flags.GivenOrImplicit
 import util.{FreshNameCreator, NoSource, SimpleIdentityMap, SourceFile}
 import typer.{Implicits, ImportInfo, Inliner, NamerContextOps, SearchHistory, SearchRoot, TypeAssigner, Typer}
 import Implicits.ContextualImplicits
@@ -214,7 +214,7 @@ object Contexts {
         implicitsCache = {
           val implicitRefs: List[ImplicitRef] =
             if (isClassDefContext)
-              try owner.thisType.implicitMembers(DelegateOrGivenOrImplicit)
+              try owner.thisType.implicitMembers(GivenOrImplicit)
               catch {
                 case ex: CyclicReference => Nil
               }
@@ -404,7 +404,7 @@ object Contexts {
         case _               => None
       }
       ctx.fresh.setImportInfo(
-        ImportInfo(sym, imp.selectors, impNameOpt, imp.importDelegate))
+        ImportInfo(sym, imp.selectors, impNameOpt, imp.importGiven))
     }
 
     /** Does current phase use an erased types interpretation? */

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

@@ -22,7 +22,7 @@ object Flags {
 
   type Flag = opaques.Flag
 
-  delegate FlagOps {
+  given FlagOps {
 
     def (x: FlagSet) bits: Long = opaques.toBits(x)
 
@@ -338,8 +338,6 @@ object Flags {
   /** Symbol is a Java default method */
   val (_, DefaultMethod @ _, _) = newFlags(38, "<defaultmethod>")
 
-  val (Delegate @ _, _, _) = newFlags(39, "delegate")
-
   /** Symbol is an enum class or enum case (if used with case) */
   val (Enum @ _, _, _) = newFlags(40, "<enum>")
 
@@ -421,7 +419,7 @@ object Flags {
 
   /** Flags representing source modifiers */
   private val CommonSourceModifierFlags: FlagSet =
-    commonFlags(Private, Protected, Final, Case, Implicit, Delegate, Given, Override, JavaStatic)
+    commonFlags(Private, Protected, Final, Case, Implicit, Given, Override, JavaStatic)
 
   val TypeSourceModifierFlags: FlagSet =
     CommonSourceModifierFlags.toTypeFlags | Abstract | Sealed | Opaque
@@ -443,7 +441,7 @@ object Flags {
     HigherKinded, Param, ParamAccessor,
     Scala2ExistentialCommon, Mutable, Opaque, Touched, JavaStatic,
     OuterOrCovariant, LabelOrContravariant, CaseAccessor,
-    Extension, NonMember, Implicit, Given, Delegate, Permanent, Synthetic,
+    Extension, NonMember, Implicit, Given, Permanent, Synthetic,
     SuperAccessorOrScala2x, Inline)
 
   /** Flags that are not (re)set when completing the denotation, or, if symbol is
@@ -502,14 +500,14 @@ object Flags {
 
   /** Flags that can apply to a module val */
   val RetainedModuleValFlags: FlagSet = RetainedModuleValAndClassFlags |
-    Override | Final | Method | Implicit | Delegate | Lazy |
+    Override | Final | Method | Implicit | Given | Lazy |
     Accessor | AbsOverride | StableRealizable | Captured | Synchronized | Erased
 
   /** Flags that can apply to a module class */
   val RetainedModuleClassFlags: FlagSet = RetainedModuleValAndClassFlags | Enum
 
   /** Flags retained in export forwarders */
-  val RetainedExportFlags = Delegate | Given | Implicit | Extension
+  val RetainedExportFlags = Given | Implicit | Extension
 
 // ------- Other flag sets -------------------------------------
 
@@ -528,10 +526,6 @@ object Flags {
   val DeferredOrLazyOrMethod: FlagSet        = Deferred | Lazy | Method
   val DeferredOrTermParamOrAccessor: FlagSet = Deferred | ParamAccessor | TermParam           // term symbols without right-hand sides
   val DeferredOrTypeParam: FlagSet           = Deferred | TypeParam                           // type symbols without right-hand sides
-  val DelegateOrGiven: FlagSet               = Delegate | Given
-  val DelegateOrGivenOrImplicit: FlagSet     = Delegate | Given | Implicit
-  val DelegateOrGivenOrImplicitVal: FlagSet  = DelegateOrGivenOrImplicit.toTermFlags
-  val DelegateOrImplicit: FlagSet            = Delegate | Implicit
   val EnumValue: FlagSet                     = Enum | JavaStatic | StableRealizable           // A Scala enum value
   val StableOrErased: FlagSet                = Erased | StableRealizable                      // Assumed to be pure
   val ExtensionMethod: FlagSet               = Extension | Method
@@ -540,6 +534,7 @@ object Flags {
   val EffectivelyFinalFlags: FlagSet         = Final | Private
   val FinalOrSealed: FlagSet                 = Final | Sealed
   val GivenOrImplicit: FlagSet               = Given | Implicit
+  val GivenOrImplicitVal: FlagSet            = GivenOrImplicit.toTermFlags
   val InlineOrProxy: FlagSet                 = Inline | InlineProxy                           // An inline method or inline argument proxy */
   val InlineMethod: FlagSet                  = Inline | Method
   val InlineParam: FlagSet                   = Inline | Param
@@ -570,7 +565,7 @@ object Flags {
   val Scala2Trait: FlagSet                   = Scala2x | Trait
   val SyntheticArtifact: FlagSet             = Synthetic | Artifact
   val SyntheticCase: FlagSet                 = Synthetic | Case
-  val SyntheticDelegateMethod: FlagSet       = Synthetic | Delegate | Method
+  val SyntheticGivenMethod: FlagSet          = Synthetic | Given | Method
   val SyntheticModule: FlagSet               = Synthetic | Module
   val SyntheticOpaque: FlagSet               = Synthetic | Opaque
   val SyntheticTermParam: FlagSet            = Synthetic | TermParam

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

@@ -409,7 +409,7 @@ object Scopes {
       var irefs = new mutable.ListBuffer[TermRef]
       var e = lastEntry
       while (e ne null) {
-        if (e.sym.isOneOf(DelegateOrGivenOrImplicit)) {
+        if (e.sym.isOneOf(GivenOrImplicit)) {
           val d = e.sym.denot
           irefs += TermRef(NoPrefix, d.symbol.asTerm).withDenot(d)
         }

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

@@ -1980,7 +1980,7 @@ object SymDenotations {
           if (keepOnly eq implicitFilter)
             if (this.is(Package)) Iterator.empty
               // implicits in package objects are added by the overriding `memberNames` in `PackageClassDenotation`
-            else info.decls.iterator.filter(_.isOneOf(DelegateOrGivenOrImplicit))
+            else info.decls.iterator.filter(_.isOneOf(GivenOrImplicit))
           else info.decls.iterator
         for (sym <- ownSyms) maybeAdd(sym.name)
         names

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

@@ -142,7 +142,7 @@ class CyclicReference private (val denot: SymDenotation) extends TypeError {
         }
       }
       // Give up and give generic errors.
-      else if (cycleSym.isOneOf(DelegateOrGivenOrImplicit, butNot = Method) && cycleSym.owner.isTerm)
+      else if (cycleSym.isOneOf(GivenOrImplicit, butNot = Method) && cycleSym.owner.isTerm)
         CyclicReferenceInvolvingImplicit(cycleSym)
       else
         CyclicReferenceInvolving(denot)