Merge pull request #217 from dotty-staging/transform/mixin

Transform/mixin

Author: DarkDimius

src/dotty/tools/dotc/Compiler.scala

@@ -46,14 +46,16 @@ class Compiler {
            new TailRec),
       List(new PatternMatcher,
            new ExplicitOuter,
-           // new LazyValTranformContext().transformer, // disabled, awaiting fixes
            new Splitter),
       List(new ElimByName,
            new InterceptedMethods,
            new Literalize,
-           new GettersSetters),
+           new Getters,
+           new ResolveSuper),
       List(new Erasure),
-      List(new CapturedVars,
+      List(new Mixin,
+           new Memoize, // TODO: Make LazyVals a part of this phase
+           new CapturedVars,
            new Constructors),
       List(new LambdaLift,
            new Flatten,

src/dotty/tools/dotc/TypeErasure.scala

@@ -4,6 +4,7 @@ package core
 
 import Symbols._, Types._, Contexts._, Flags._, Names._, StdNames._, Decorators._, Flags.JavaDefined
 import dotc.transform.ExplicitOuter._
+import typer.Mode
 import util.DotClass
 
 /** Erased types are:
@@ -89,7 +90,7 @@ object TypeErasure {
 
   /** The current context with a phase no later than erasure */
   private def erasureCtx(implicit ctx: Context) =
-    if (ctx.erasedTypes) ctx.withPhase(ctx.erasurePhase) else ctx
+    if (ctx.erasedTypes) ctx.withPhase(ctx.erasurePhase).addMode(Mode.FutureDefsOK) else ctx
 
   def erasure(tp: Type)(implicit ctx: Context): Type = scalaErasureFn(tp)(erasureCtx)
   def semiErasure(tp: Type)(implicit ctx: Context): Type = semiErasureFn(tp)(erasureCtx)
@@ -107,6 +108,8 @@ object TypeErasure {
     case tp: TermRef =>
       assert(tp.symbol.exists, tp)
       TermRef(erasedRef(tp.prefix), tp.symbol.asTerm)
+    case tp: ThisType =>
+      tp
     case tp =>
       erasure(tp)
   }
@@ -141,7 +144,12 @@ object TypeErasure {
     if ((sym eq defn.Any_asInstanceOf) || (sym eq defn.Any_isInstanceOf)) eraseParamBounds(sym.info.asInstanceOf[PolyType])
     else if (sym.isAbstractType) TypeAlias(WildcardType)
     else if (sym.isConstructor) outer.addParam(sym.owner.asClass, erase(tp)(erasureCtx))
-    else eraseInfo(tp)(erasureCtx)
+    else eraseInfo(tp)(erasureCtx) match {
+      case einfo: MethodType if sym.isGetter && einfo.resultType.isRef(defn.UnitClass) =>
+        defn.BoxedUnitClass.typeRef
+      case einfo =>
+        einfo
+    }
   }
 
   def isUnboundedGeneric(tp: Type)(implicit ctx: Context) = !(
@@ -265,7 +273,7 @@ class TypeErasure(isJava: Boolean, isSemi: Boolean, isConstructor: Boolean, wild
     case tp: TermRef =>
       this(tp.widen)
     case ThisType(_) =>
-      tp
+      this(tp.widen)
     case SuperType(thistpe, supertpe) =>
       SuperType(this(thistpe), this(supertpe))
     case ExprType(rt) =>
@@ -319,7 +327,7 @@ class TypeErasure(isJava: Boolean, isSemi: Boolean, isConstructor: Boolean, wild
   }
 
   def eraseInfo(tp: Type)(implicit ctx: Context) = tp match {
-    case ExprType(rt) => MethodType(Nil, Nil, erasure(rt))
+    case ExprType(rt) => MethodType(Nil, Nil, eraseResult(rt))
     case tp => erasure(tp)
   }
 

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

@@ -6,7 +6,7 @@ import transform.SymUtils._
 import core._
 import util.Positions._, Types._, Contexts._, Constants._, Names._, Flags._
 import SymDenotations._, Symbols._, StdNames._, Annotations._, Trees._, Symbols._
-import Denotations._, Decorators._
+import Denotations._, Decorators._, DenotTransformers._
 import config.Printers._
 import typer.Mode
 import collection.mutable
@@ -39,8 +39,8 @@ object tpd extends Trees.Instance[Type] with TypedTreeInfo {
   def This(cls: ClassSymbol)(implicit ctx: Context): This =
     untpd.This(cls.name).withType(cls.thisType)
 
-  def Super(qual: Tree, mix: TypeName, inConstrCall: Boolean)(implicit ctx: Context): Super =
-    ta.assignType(untpd.Super(qual, mix), qual, inConstrCall)
+  def Super(qual: Tree, mix: TypeName, inConstrCall: Boolean, mixinClass: Symbol = NoSymbol)(implicit ctx: Context): Super =
+    ta.assignType(untpd.Super(qual, mix), qual, inConstrCall, mixinClass)
 
   def Apply(fn: Tree, args: List[Tree])(implicit ctx: Context): Apply =
     ta.assignType(untpd.Apply(fn, args), fn, args)
@@ -527,7 +527,8 @@ object tpd extends Trees.Instance[Type] with TypedTreeInfo {
      */
     def changeOwner(from: Symbol, to: Symbol)(implicit ctx: Context): ThisTree = {
       def loop(from: Symbol, froms: List[Symbol], tos: List[Symbol]): ThisTree = {
-        if (from.isWeakOwner) loop(from.owner, from :: froms, to :: tos)
+        if (from.isWeakOwner && !from.owner.isClass)
+          loop(from.owner, from :: froms, to :: tos)
         else {
           //println(i"change owner ${from :: froms}%, % ==> $tos of $tree")
           new TreeTypeMap(oldOwners = from :: froms, newOwners = tos).apply(tree)
@@ -536,6 +537,26 @@ object tpd extends Trees.Instance[Type] with TypedTreeInfo {
       loop(from, Nil, to :: Nil)
     }
 
+    /** After phase `trans`, set the owner of every definition in this tree that was formerly
+     *  owner by `from` to `to`.
+     */
+    def changeOwnerAfter(from: Symbol, to: Symbol, trans: DenotTransformer)(implicit ctx: Context): ThisTree = {
+      assert(ctx.phase == trans.next)
+      val traverser = new TreeTraverser {
+        def traverse(tree: Tree) = tree match {
+          case tree: DefTree =>
+            val sym = tree.symbol
+            if (sym.denot(ctx.withPhase(trans)).owner == from)
+              sym.copySymDenotation(owner = to).installAfter(trans)
+            if (sym.isWeakOwner) traverseChildren(tree)
+          case _ =>
+            traverseChildren(tree)
+        }
+      }
+      traverser.traverse(tree)
+      tree
+    }
+
     def select(name: Name)(implicit ctx: Context): Select =
       Select(tree, name)
 

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

@@ -107,8 +107,9 @@ class ScalaSettings extends Settings.SettingGroup {
   val Xdce = BooleanSetting("-Ydead-code", "Perform dead code elimination.")
   val debug = BooleanSetting("-Ydebug", "Increase the quantity of debugging output.")
   val debugNames = BooleanSetting("-YdebugNames", "Show name-space indicators when printing names")
-  val debugTrace = BooleanSetting("-YdebugTrace", "Trace core operations")
-  val debugFlags = BooleanSetting("-YdebugFlags", "Print all flags of definitions")
+  val debugTrace = BooleanSetting("-Ydebug-trace", "Trace core operations")
+  val debugFlags = BooleanSetting("-Ydebug-flags", "Print all flags of definitions")
+  val debugOwners = BooleanSetting("-Ydebug-owners", "Print all owners of definitions (requires -Yprint-syms)")
   //val doc           = BooleanSetting    ("-Ydoc", "Generate documentation")
   val termConflict = ChoiceSetting("-Yresolve-term-conflict", "strategy", "Resolve term conflicts", List("package", "object", "error"), "error")
   val inline = BooleanSetting("-Yinline", "Perform inlining when possible.")

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

@@ -297,16 +297,21 @@ object Contexts {
     def thisCallArgContext: Context = {
       assert(owner.isClassConstructor)
       val constrCtx = outersIterator.dropWhile(_.outer.owner == owner).next
-      var classCtx = outersIterator.dropWhile(!_.isClassDefContext).next
-      classCtx.superOrThisCallContext(owner, constrCtx.scope).setTyperState(typerState)
+      superOrThisCallContext(owner, constrCtx.scope).setTyperState(typerState)
     }
 
     /** The super= or this-call context with given owner and locals. */
     private def superOrThisCallContext(owner: Symbol, locals: Scope): FreshContext = {
-      assert(isClassDefContext)
-      outer.fresh.setOwner(owner).setScope(locals).setMode(ctx.mode | Mode.InSuperCall)
+      var classCtx = outersIterator.dropWhile(!_.isClassDefContext).next
+      classCtx.outer.fresh.setOwner(owner).setScope(locals).setMode(classCtx.mode | Mode.InSuperCall)
     }
 
+    /** The context of expression `expr` seen as a member of a statement sequence */
+    def exprContext(stat: Tree[_ >: Untyped], exprOwner: Symbol) =
+      if (exprOwner == this.owner) this
+      else if (untpd.isSuperConstrCall(stat) && this.owner.isClass) superCallContext
+      else ctx.fresh.setOwner(exprOwner)
+
     /** The current source file; will be derived from current
      *  compilation unit.
      */

src/dotty/tools/dotc/core/Denotations.scala

@@ -202,7 +202,7 @@ object Denotations {
     def requiredClass(name: PreName)(implicit ctx: Context): ClassSymbol =
       info.member(name.toTypeName).requiredSymbol(_.isClass).asClass
 
-    /** The denotation that has a type matching `targetType` when seen
+    /** The alternative of this denotation that has a type matching `targetType` when seen
      *  as a member of type `site`, `NoDenotation` if none exists.
      */
     def matchingDenotation(site: Type, targetType: Type)(implicit ctx: Context): SingleDenotation =

src/dotty/tools/dotc/core/NameOps.scala

@@ -47,13 +47,15 @@ object NameOps {
     }
   }
 
-  object SuperAccessorName {
-    val pre = nme.SUPER_PREFIX
+  class PrefixNameExtractor(pre: TermName) {
     def apply(name: TermName): TermName = pre ++ name
     def unapply(name: TermName): Option[TermName] =
       if (name startsWith pre) Some(name.drop(pre.length).asTermName) else None
   }
 
+  object SuperAccessorName extends PrefixNameExtractor(nme.SUPER_PREFIX)
+  object InitializerName extends PrefixNameExtractor(nme.INITIALIZER_PREFIX)
+
   implicit class NameDecorator[N <: Name](val name: N) extends AnyVal {
     import nme._
 
@@ -68,14 +70,13 @@ object NameOps {
     def isProtectedAccessorName = name startsWith PROTECTED_PREFIX
     def isReplWrapperName = name containsSlice INTERPRETER_IMPORT_WRAPPER
     def isSetterName = name endsWith SETTER_SUFFIX
-    def isTraitSetterName = isSetterName && (name containsSlice TRAIT_SETTER_PREFIX)
     def isSingletonName = name endsWith SINGLETON_SUFFIX
     def isModuleClassName = name endsWith MODULE_SUFFIX
     def isImportName = name startsWith IMPORT
     def isFieldName = name endsWith LOCAL_SUFFIX
     def isInheritedName = name.length > 0 && name.head == '(' && name.startsWith(nme.INHERITED)
     def isDefaultGetterName = name.isTermName && name.asTermName.defaultGetterIndex >= 0
-
+    def isScala2LocalSuffix = name.endsWith(" ")
     def isModuleVarName(name: Name): Boolean =
       name.stripAnonNumberSuffix endsWith MODULE_VAR_SUFFIX
 
@@ -224,9 +225,6 @@ object NameOps {
   implicit class TermNameDecorator(val name: TermName) extends AnyVal {
     import nme._
 
-    def traitSetterName: TermName =
-      nme.TRAIT_SETTER_PREFIX ++ setterName
-
     def setterName: TermName =
       if (name.isFieldName) name.fieldToGetter.setterName
       else name ++ SETTER_SUFFIX
@@ -240,13 +238,8 @@ object NameOps {
       else name ++ LOCAL_SUFFIX
 
     private def setterToGetter: TermName = {
-      val p = name.indexOfSlice(TRAIT_SETTER_PREFIX)
-      if (p >= 0)
-        (name drop (p + TRAIT_SETTER_PREFIX.length)).asTermName.getterName
-      else {
-        assert(name.endsWith(SETTER_SUFFIX), name + " is referenced as a setter but has wrong name format")
-        name.take(name.length - SETTER_SUFFIX.length).asTermName
-      }
+      assert(name.endsWith(SETTER_SUFFIX), name + " is referenced as a setter but has wrong name format")
+      name.take(name.length - SETTER_SUFFIX.length).asTermName
     }
 
     def fieldToGetter: TermName = {
@@ -283,6 +276,9 @@ object NameOps {
         -1
     }
 
+    def stripScala2LocalSuffix: TermName =
+      if (name.isScala2LocalSuffix) name.init.asTermName else name
+
     /** The name of an accessor for protected symbols. */
     def protectedAccessorName: TermName =
       PROTECTED_PREFIX ++ name.unexpandedName()

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

@@ -20,7 +20,7 @@ import printing.Printer
 import util.common._
 import util.DotClass
 import SymDenotations.NoDenotation
-import collection.mutable.ListBuffer
+import collection.mutable
 
 object Scopes {
 
@@ -172,12 +172,27 @@ object Scopes {
      */
     private var elemsCache: List[Symbol] = null
 
-    def cloneScope(implicit ctx: Context): MutableScope = newScopeWith(this.toList: _*)
+    /** Clone scope, taking care not to force the denotations of any symbols in the scope.
+     */
+    def cloneScope(implicit ctx: Context): MutableScope = {
+      val entries = new mutable.ArrayBuffer[ScopeEntry]
+      var e = lastEntry
+      while ((e ne null) && e.owner == this) {
+        entries += e
+        e = e.prev
+      }
+      val scope = newScope
+      for (i <- entries.length - 1 to 0 by -1) {
+        val e = entries(i)
+        scope.newScopeEntry(e.name, e.sym)
+      }
+      scope
+    }
 
-    /** create and enter a scope entry */
-    protected def newScopeEntry(sym: Symbol)(implicit ctx: Context): ScopeEntry = {
+    /** create and enter a scope entry with given name and symbol */
+    protected def newScopeEntry(name: Name, sym: Symbol)(implicit ctx: Context): ScopeEntry = {
       ensureCapacity(if (hashTable ne null) hashTable.length else MinHash)
-      val e = new ScopeEntry(sym.name, sym, this)
+      val e = new ScopeEntry(name, sym, this)
       e.prev = lastEntry
       lastEntry = e
       if (hashTable ne null) enterInHash(e)
@@ -186,6 +201,10 @@ object Scopes {
       e
     }
 
+    /** create and enter a scope entry */
+    protected def newScopeEntry(sym: Symbol)(implicit ctx: Context): ScopeEntry =
+      newScopeEntry(sym.name, sym)
+
     private def enterInHash(e: ScopeEntry)(implicit ctx: Context): Unit = {
       val idx = e.name.hashCode & (hashTable.length - 1)
       e.tail = hashTable(idx)
@@ -325,7 +344,7 @@ object Scopes {
     }
 
     override def implicitDecls(implicit ctx: Context): List[TermRef] = {
-      var irefs = new ListBuffer[TermRef]
+      var irefs = new mutable.ListBuffer[TermRef]
       var e = lastEntry
       while (e ne null) {
         if (e.sym is Implicit) {

src/dotty/tools/dotc/core/StdNames.scala

@@ -119,9 +119,9 @@ object StdNames {
     val SINGLETON_SUFFIX: N           = ".type"
     val SPECIALIZED_SUFFIX: N         = "$sp"
     val SUPER_PREFIX: N               = "super$"
-    val TRAIT_SETTER_PREFIX: N        = "_setter_$"
     val WHILE_PREFIX: N               = "while$"
-    val DEFAULT_EXCEPTION_NAME: N = "ex$"
+    val DEFAULT_EXCEPTION_NAME: N     = "ex$"
+    val INITIALIZER_PREFIX: N         = "initial$"
 
     // value types (and AnyRef) are all used as terms as well
     // as (at least) arguments to the @specialize annotation.

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

@@ -425,10 +425,14 @@ object SymDenotations {
     final def isSourceMethod(implicit ctx: Context) = this is (Method, butNot = Accessor)
 
     /** Is this a setter? */
-    final def isGetter(implicit ctx: Context) = (this is Accessor) && !originalName.isSetterName
+    final def isGetter(implicit ctx: Context) =
+      (this is Accessor) && !originalName.isSetterName && !originalName.isScala2LocalSuffix
 
     /** Is this a setter? */
-    final def isSetter(implicit ctx: Context) = (this is Accessor) && originalName.isSetterName
+    final def isSetter(implicit ctx: Context) =
+      (this is Accessor) &&
+      originalName.isSetterName &&
+      info.firstParamTypes.nonEmpty // to avoid being fooled by   var x_= : Unit = ...
 
     /** is this the constructor of a class? */
     final def isClassConstructor = name == nme.CONSTRUCTOR
@@ -560,7 +564,7 @@ object SymDenotations {
     def membersNeedAsSeenFrom(pre: Type)(implicit ctx: Context) =
       !(  this.isTerm
        || this.isStaticOwner
-       || ctx.erasedTypes && symbol != defn.ArrayClass
+       || ctx.erasedTypes
        || (pre eq NoPrefix) || (pre eq thisType)
        )