Generalize RefTypes

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

@@ -431,11 +431,11 @@ class DottyBackendInterface(outputDirectory: AbstractFile, val superCallsMap: Ma
     var found = desugared.get(i.tpe)
     if (found == null) {
       i.tpe match {
-        case TermRef(prefix: TermRef, name) =>
+        case TermRef(prefix: TermRef, _) =>
           found = tpd.ref(prefix).select(i.symbol)
-        case TermRef(prefix: ThisType, name) =>
+        case TermRef(prefix: ThisType, _) =>
           found = tpd.This(prefix.cls).select(i.symbol)
-        case TermRef(NoPrefix, name) =>
+        case TermRef(NoPrefix, _) =>
           if (i.symbol is Flags.Method) found = This(i.symbol.topLevelClass).select(i.symbol) // workaround #342 todo: remove after fixed
         case _ =>
       }

compiler/src/dotty/tools/dotc/Run.scala

@@ -105,7 +105,7 @@ class Run(comp: Compiler, ictx: Context) {
     compileUnits()(ctx)
   }
 
-  protected def compileUnits()(implicit ctx: Context) = Stats.monitorHeartBeat {
+  protected def compileUnits()(implicit ctx: Context) = Stats.maybeMonitored {
     ctx.checkSingleThreaded()
 
     // If testing pickler, make sure to stop after pickling phase:
@@ -118,20 +118,21 @@ class Run(comp: Compiler, ictx: Context) {
     ctx.usePhases(phases)
     var lastPrintedTree: PrintedTree = NoPrintedTree
     for (phase <- ctx.allPhases)
-      if (phase.isRunnable) {
-        val start = System.currentTimeMillis
-        units = phase.runOn(units)
-        if (ctx.settings.Xprint.value.containsPhase(phase)) {
-          for (unit <- units) {
-            lastPrintedTree =
-              printTree(lastPrintedTree)(ctx.fresh.setPhase(phase.next).setCompilationUnit(unit))
+      if (phase.isRunnable)
+        Stats.trackTime(s"$phase ms ") {
+          val start = System.currentTimeMillis
+          units = phase.runOn(units)
+          if (ctx.settings.Xprint.value.containsPhase(phase)) {
+            for (unit <- units) {
+              lastPrintedTree =
+                printTree(lastPrintedTree)(ctx.fresh.setPhase(phase.next).setCompilationUnit(unit))
+            }
           }
+          ctx.informTime(s"$phase ", start)
+          Stats.record(s"total trees at end of $phase", ast.Trees.ntrees)
+          for (unit <- units)
+            Stats.record(s"retained typed trees at end of $phase", unit.tpdTree.treeSize)
         }
-        ctx.informTime(s"$phase ", start)
-        Stats.record(s"total trees at end of $phase", ast.Trees.ntrees)
-        for (unit <- units)
-          Stats.record(s"retained typed trees at end of $phase", unit.tpdTree.treeSize)
-      }
     if (!ctx.reporter.hasErrors) Rewrites.writeBack()
   }
 

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

@@ -5,7 +5,7 @@ package ast
 import core._
 import util.Positions._, Types._, Contexts._, Constants._, Names._, NameOps._, Flags._
 import SymDenotations._, Symbols._, StdNames._, Annotations._, Trees._
-import Decorators._
+import Decorators._, transform.SymUtils._
 import NameKinds.{UniqueName, EvidenceParamName, DefaultGetterName}
 import language.higherKinds
 import typer.FrontEnd
@@ -70,7 +70,7 @@ object desugar {
         def apply(tp: Type) = tp match {
           case tp: NamedType if tp.symbol.exists && (tp.symbol.owner eq originalOwner) =>
             val defctx = ctx.outersIterator.dropWhile(_.scope eq ctx.scope).next()
-            var local = defctx.denotNamed(tp.name).suchThat(_ is ParamOrAccessor).symbol
+            var local = defctx.denotNamed(tp.name).suchThat(_.isParamOrAccessor).symbol
             if (local.exists) (defctx.owner.thisType select local).dealias
             else {
               def msg =
@@ -238,23 +238,6 @@ object desugar {
         Nil
     }
 
-  /** Fill in empty type bounds with Nothing/Any. Expand private local type parameters as follows:
-   *
-   *     class C[v T]
-   * ==>
-   *     class C { type v C$T; type v T = C$T }
-   */
-  def typeDef(tdef: TypeDef)(implicit ctx: Context): Tree = {
-    if (tdef.mods is PrivateLocalParam) {
-      val tparam = cpy.TypeDef(tdef)(name = tdef.name.expandedName(ctx.owner))
-        .withMods(tdef.mods &~ PrivateLocal)
-      val alias = cpy.TypeDef(tdef)(rhs = refOfDef(tparam))
-        .withMods(tdef.mods & VarianceFlags | PrivateLocalParamAccessor | Synthetic)
-      Thicket(tparam, alias)
-    }
-    else tdef
-  }
-
   @sharable private val synthetic = Modifiers(Synthetic)
 
   private def toDefParam(tparam: TypeDef): TypeDef =
@@ -696,7 +679,7 @@ object desugar {
 
   def defTree(tree: Tree)(implicit ctx: Context): Tree = tree match {
     case tree: ValDef => valDef(tree)
-    case tree: TypeDef => if (tree.isClassDef) classDef(tree) else typeDef(tree)
+    case tree: TypeDef => if (tree.isClassDef) classDef(tree) else tree
     case tree: DefDef => defDef(tree)
     case tree: ModuleDef => moduleDef(tree)
     case tree: PatDef => patDef(tree)
@@ -1074,7 +1057,7 @@ object desugar {
         } else if (arity == 1) ts.head
         else if (ctx.mode is Mode.Type) AppliedTypeTree(ref(tupleTypeRef), ts)
         else if (arity == 0) unitLiteral
-        else Apply(ref(tupleTypeRef.classSymbol.companionModule.valRef), ts)
+        else Apply(ref(tupleTypeRef.classSymbol.companionModule.termRef), ts)
       case WhileDo(cond, body) =>
         // { <label> def while$(): Unit = if (cond) { body; while$() } ; while$() }
         val call = Apply(Ident(nme.WHILE_PREFIX), Nil).withPos(tree.pos)
@@ -1132,7 +1115,7 @@ object desugar {
    */
   def refinedTypeToClass(parent: tpd.Tree, refinements: List[Tree])(implicit ctx: Context): TypeDef = {
     def stripToCore(tp: Type): List[Type] = tp match {
-      case tp: RefinedType if tp.argInfos.nonEmpty => tp :: Nil // parameterized class type
+      case tp: AppliedType => tp :: Nil
       case tp: TypeRef if tp.symbol.isClass => tp :: Nil     // monomorphic class type
       case tp: TypeProxy => stripToCore(tp.underlying)
       case AndType(tp1, tp2) => stripToCore(tp1) ::: stripToCore(tp2)

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

@@ -86,7 +86,10 @@ object Trees {
      *  where we overwrite with a simplified version of the type itself.
      */
     private[dotc] def overwriteType(tpe: T) = {
-      if (this.isInstanceOf[Template[_]]) assert(tpe.isInstanceOf[WithFixedSym], s"$this <--- $tpe")
+      if (this.isInstanceOf[Template[_]])
+        tpe match {
+          case tpe: TermRef => assert(tpe.hasFixedSym , s"$this <--- $tpe")
+        }
       myTpe = tpe
     }
 

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

@@ -6,7 +6,7 @@ import dotty.tools.dotc.transform.{ExplicitOuter, Erasure}
 import dotty.tools.dotc.typer.ProtoTypes.FunProtoTyped
 import transform.SymUtils._
 import core._
-import util.Positions._, Types._, Contexts._, Constants._, Names._, Flags._
+import util.Positions._, Types._, Contexts._, Constants._, Names._, Flags._, NameOps._
 import SymDenotations._, Symbols._, StdNames._, Annotations._, Trees._, Symbols._
 import Denotations._, Decorators._, DenotTransformers._
 import collection.mutable
@@ -213,8 +213,7 @@ object tpd extends Trees.Instance[Type] with TypedTreeInfo {
     ta.assignType(untpd.TypeDef(sym.name, TypeTree(sym.info)), sym)
 
   def ClassDef(cls: ClassSymbol, constr: DefDef, body: List[Tree], superArgs: List[Tree] = Nil)(implicit ctx: Context): TypeDef = {
-    val firstParentRef :: otherParentRefs = cls.info.parents
-    val firstParent = cls.typeRef.baseTypeWithArgs(firstParentRef.symbol)
+    val firstParent :: otherParents = cls.info.parents
     val superRef =
       if (cls is Trait) TypeTree(firstParent)
       else {
@@ -229,7 +228,7 @@ object tpd extends Trees.Instance[Type] with TypedTreeInfo {
         val constr = firstParent.decl(nme.CONSTRUCTOR).suchThat(constr => isApplicable(constr.info))
         New(firstParent, constr.symbol.asTerm, superArgs)
       }
-    val parents = superRef :: otherParentRefs.map(TypeTree(_))
+    val parents = superRef :: otherParents.map(TypeTree(_))
 
     val selfType =
       if (cls.classInfo.selfInfo ne NoType) ValDef(ctx.newSelfSym(cls))
@@ -244,7 +243,7 @@ object tpd extends Trees.Instance[Type] with TypedTreeInfo {
     val localDummy = ((NoSymbol: Symbol) /: body)(findLocalDummy.apply)
       .orElse(ctx.newLocalDummy(cls))
     val impl = untpd.Template(constr, parents, selfType, newTypeParams ++ body)
-      .withType(localDummy.nonMemberTermRef)
+      .withType(localDummy.termRef)
     ta.assignType(untpd.TypeDef(cls.name, impl), cls)
   }
 
@@ -305,7 +304,7 @@ object tpd extends Trees.Instance[Type] with TypedTreeInfo {
         true
       case pre: ThisType =>
         pre.cls.isStaticOwner ||
-          tp.symbol.is(ParamOrAccessor) && !pre.cls.is(Trait) && ctx.owner.enclosingClass == pre.cls
+          tp.symbol.isParamOrAccessor && !pre.cls.is(Trait) && ctx.owner.enclosingClass == pre.cls
           // was ctx.owner.enclosingClass.derivesFrom(pre.cls) which was not tight enough
           // and was spuriously triggered in case inner class would inherit from outer one
           // eg anonymous TypeMap inside TypeMap.andThen
@@ -381,9 +380,9 @@ object tpd extends Trees.Instance[Type] with TypedTreeInfo {
   /** new C(args), calling given constructor `constr` of C */
   def New(tp: Type, constr: TermSymbol, args: List[Tree])(implicit ctx: Context): Apply = {
     val targs = tp.argTypes
-    val tycon = tp.withoutArgs(targs)
+    val tycon = tp.typeConstructor
     New(tycon)
-      .select(TermRef.withSig(tycon, constr))
+      .select(TermRef.withSym(tycon, constr))
       .appliedToTypes(targs)
       .appliedToArgs(args)
   }
@@ -698,19 +697,19 @@ object tpd extends Trees.Instance[Type] with TypedTreeInfo {
      */
     def select(sym: Symbol)(implicit ctx: Context): Select = {
       val tp =
-        if (sym.isType)
+        if (sym.isType) {
+          assert(!sym.is(TypeParam))
           TypeRef(tree.tpe, sym.name.asTypeName)
+        }
         else
-          TermRef.withSigAndDenot(tree.tpe, sym.name.asTermName,
-            sym.signature, sym.denot.asSeenFrom(tree.tpe))
-      untpd.Select(tree, sym.name)
-        .withType(tp)
+          TermRef(tree.tpe, sym.name.asTermName, sym.denot.asSeenFrom(tree.tpe))
+      untpd.Select(tree, sym.name).withType(tp)
     }
 
     /** A select node with the given selector name and signature and a computed type */
     def selectWithSig(name: Name, sig: Signature)(implicit ctx: Context): Tree =
       untpd.SelectWithSig(tree, name, sig)
-        .withType(TermRef.withSig(tree.tpe, name.asTermName, sig))
+        .withType(TermRef(tree.tpe, name.asTermName.withSig(sig)))
 
     /** A select node with selector name and signature taken from `sym`.
      *  Note: Use this method instead of select(sym) if the referenced symbol
@@ -918,7 +917,7 @@ object tpd extends Trees.Instance[Type] with TypedTreeInfo {
       }
       else denot.asSingleDenotation.termRef
     val fun = receiver
-      .select(TermRef.withSig(receiver.tpe, selected.termSymbol.asTerm))
+      .select(TermRef.withSym(receiver.tpe, selected.termSymbol.asTerm))
       .appliedToTypes(targs)
 
     def adaptLastArg(lastParam: Tree, expectedType: Type) = {

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

@@ -296,9 +296,9 @@ object untpd extends Trees.Instance[Untyped] with UntypedTreeInfo {
         (tycon, targs)
       case TypedSplice(AppliedTypeTree(tycon, targs)) =>
         (TypedSplice(tycon), targs map (TypedSplice(_)))
-      case TypedSplice(tpt1: Tree) =>
+      case TypedSplice(tpt1: tpd.Tree) =>
+        val tycon = tpt1.tpe.typeConstructor
         val argTypes = tpt1.tpe.argTypesLo
-        val tycon = tpt1.tpe.withoutArgs(argTypes)
         def wrap(tpe: Type) = TypeTree(tpe) withPos tpt.pos
         (wrap(tycon), argTypes map wrap)
       case _ =>

compiler/src/dotty/tools/dotc/config/Config.scala

@@ -84,19 +84,12 @@ object Config {
   /** If this flag is set, take the fast path when comparing same-named type-aliases and types */
   final val fastPathForRefinedSubtype = true
 
-  /** If this flag is set, `TypeOps.normalizeToClassRefs` will insert forwarders
-   *  for type parameters of base classes. This is an optimization, which avoids
-   *  long alias chains. We should  not rely on the optimization, though. So changing
-   *  the flag to false can be used for checking that everything works OK without it.
-   */
-  final val forwardTypeParams = true
-
-  /** If this flag is set, and we compute `T1 { X = S1 }` & `T2 { X = S2 }` as a new
-   *  upper bound of a constrained parameter, try to align the refinements by computing
+  /** If this flag is set, and we compute `T1[X1]` & `T2[X2]` as a new
+   *  upper bound of a constrained parameter, try to align the arguments by computing
    *  `S1 =:= S2` (which might instantiate type parameters).
    *  This rule is contentious because it cuts the constraint set.
    *
-   *  For more info, see the comment in `TypeComparer#distributeAnd`.
+   *  For more info, see the comment in `TypeComparer#glbArgs`.
    */
   final val alignArgsInAnd = true
 
@@ -113,6 +106,13 @@ object Config {
    */
   final val checkTypeRefCycles = false
 
+  /** If this flag is set, it is checked that class type parameters are
+   *  only references with NoPrefix or ThisTypes as prefixes. This option
+   *  is usally disabled, because there are still some legitimate cases where
+   *  this can arise (e.g. for pos/Map.scala, in LambdaType.integrate).
+   */
+  final val checkTypeParamRefs = false
+
   /** The recursion depth for showing a summarized string */
   final val summarizeDepth = 2
 

compiler/src/dotty/tools/dotc/config/ScalaSettings.scala

@@ -67,7 +67,6 @@ class ScalaSettings extends Settings.SettingGroup {
   val Ycheck = PhasesSetting("-Ycheck", "Check the tree at the end of")
   val YcheckMods = BooleanSetting("-Ycheck-mods", "Check that symbols and their defining trees have modifiers in sync")
   val debug = BooleanSetting("-Ydebug", "Increase the quantity of debugging output.")
-  val debugAlias = BooleanSetting("-Ydebug-alias", "Never follow alias when printing types")
   val debugTrace = BooleanSetting("-Ydebug-trace", "Trace core operations")
   val debugFlags = BooleanSetting("-Ydebug-flags", "Print all flags of definitions")
   val debugNames = BooleanSetting("-Ydebug-names", "Show internal representation of names")
@@ -87,7 +86,8 @@ class ScalaSettings extends Settings.SettingGroup {
   val YmethodInfer = BooleanSetting("-Yinfer-argument-types", "Infer types for arguments of overriden methods.")
   val YtraceContextCreation = BooleanSetting("-Ytrace-context-creation", "Store stack trace of context creations.")
   val YshowSuppressedErrors = BooleanSetting("-Yshow-suppressed-errors", "Also show follow-on errors and warnings that are normally supressed.")
-  val Yheartbeat = BooleanSetting("-Yheartbeat", "show heartbeat stack trace of compiler operations.")
+  val YdetailedStats = BooleanSetting("-Ydetailed-stats", "show detailed internal compiler stats (needs Stats.enabled to be set to true).")
+  val Yheartbeat = BooleanSetting("-Ydetailed-stats", "show heartbeat stack trace of compiler operations (needs Stats.enabled to be set to true).")
   val Yprintpos = BooleanSetting("-Yprintpos", "show tree positions.")
   val YnoDeepSubtypes = BooleanSetting("-Yno-deep-subtypes", "throw an exception on deep subtyping call stacks.")
   val YnoPatmatOpt = BooleanSetting("-Yno-patmat-opt", "disable all pattern matching optimizations.")

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

@@ -103,7 +103,7 @@ object Annotations {
 
     private def resolveConstructor(atp: Type, args:List[Tree])(implicit ctx: Context): Tree = {
       val targs = atp.argTypes
-      tpd.applyOverloaded(New(atp withoutArgs targs), nme.CONSTRUCTOR, args, targs, atp, isAnnotConstructor = true)
+      tpd.applyOverloaded(New(atp.typeConstructor), nme.CONSTRUCTOR, args, targs, atp, isAnnotConstructor = true)
     }
 
     def applyResolve(atp: Type, args: List[Tree])(implicit ctx: Context): Annotation = {
@@ -140,7 +140,7 @@ object Annotations {
 
     def makeAlias(sym: TermSymbol)(implicit ctx: Context) =
       apply(defn.AliasAnnot, List(
-        ref(TermRef.withSigAndDenot(sym.owner.thisType, sym.name, sym.signature, sym))))
+        ref(TermRef(sym.owner.thisType, sym.name, sym))))
 
     def makeChild(delayedSym: Context => Symbol)(implicit ctx: Context): Annotation = {
       def makeChildLater(implicit ctx: Context) = {

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

@@ -33,6 +33,12 @@ object CheckRealizable {
   class HasProblemBounds(typ: SingleDenotation)(implicit ctx: Context)
   extends Realizability(i" has a member $typ with possibly conflicting bounds ${typ.info.bounds.lo} <: ... <: ${typ.info.bounds.hi}")
 
+  class HasProblemBaseArg(typ: Type, argBounds: TypeBounds)(implicit ctx: Context)
+  extends Realizability(i" has a base type $typ with possibly conflicting parameter bounds ${argBounds.lo} <: ... <: ${argBounds.hi}")
+
+  class HasProblemBase(base1: Type, base2: Type)(implicit ctx: Context)
+  extends Realizability(i" has conflicting base types $base1 and $base2")
+
   class HasProblemField(fld: SingleDenotation, problem: Realizability)(implicit ctx: Context)
   extends Realizability(i" has a member $fld which is not a legal path\n since ${fld.symbol.name}: ${fld.info}${problem.msg}")
 
@@ -89,18 +95,39 @@ class CheckRealizable(implicit ctx: Context) {
       else boundsRealizability(tp).andAlso(memberRealizability(tp))
   }
 
-  /** `Realizable` if `tp` has good bounds, a `HasProblemBounds` instance
-   *  pointing to a bad bounds member otherwise.
+  /** `Realizable` if `tp` has good bounds, a `HasProblem...` instance
+   *  pointing to a bad bounds member otherwise. "Has good bounds" means:
+   *
+   *    - all type members have good bounds
+   *    - all base types are class types, and if their arguments are wildcards
+   *      they have good bounds.
+   *    - base types do not appear in multiple instances with different arguments.
+   *      (depending on the simplification scheme for AndTypes employed, this could
+   *       also lead to base types with bad bounds).
    */
   private def boundsRealizability(tp: Type) = {
-    def hasBadBounds(mbr: SingleDenotation) = {
-      val bounds = mbr.info.bounds
-      !(bounds.lo <:< bounds.hi)
-    }
-    tp.nonClassTypeMembers.find(hasBadBounds) match {
-      case Some(mbr) => new HasProblemBounds(mbr)
-      case _ => Realizable
+    val mbrProblems =
+      for {
+        mbr <- tp.nonClassTypeMembers
+        if !(mbr.info.loBound <:< mbr.info.hiBound)
+      }
+      yield new HasProblemBounds(mbr)
+
+    def baseTypeProblems(base: Type) = base match {
+      case AndType(base1, base2) =>
+        new HasProblemBase(base1, base2) :: Nil
+      case base =>
+        base.argInfos.collect {
+          case bounds @ TypeBounds(lo, hi) if !(lo <:< hi) =>
+            new HasProblemBaseArg(base, bounds)
+        }
     }
+    val baseProblems =
+      tp.baseClasses.map(_.baseTypeOf(tp)).flatMap(baseTypeProblems)
+
+    (((Realizable: Realizability)
+      /: mbrProblems)(_ andAlso _)
+      /: baseProblems)(_ andAlso _)
   }
 
   /** `Realizable` if all of `tp`'s non-struct fields have realizable types,