Merge pull request #102 from dotty-staging/transform/erasure

Transform/erasure

Author: DarkDimius

src/dotty/tools/dotc/Compiler.scala

@@ -20,8 +20,8 @@ class Compiler {
   def phases: List[List[Phase]] =
     List(
       List(new FrontEnd),
-      List(new LazyValsCreateCompanionObjects),      //force separataion between lazyVals and LVCreateCO
-      List(new LazyValTranformContext().transformer, new TypeTestsCasts),
+      List(new LazyValsCreateCompanionObjects, new PatternMatcher),    //force separataion between lazyVals and LVCreateCO
+      List(new LazyValTranformContext().transformer, new Splitter, new TypeTestsCasts),
       List(new Erasure),
       List(new UncurryTreeTransform)
     )

src/dotty/tools/dotc/Run.scala

@@ -6,6 +6,7 @@ import Contexts._, Periods._, Symbols._, Phases._, Decorators._
 import io.PlainFile
 import util.{SourceFile, NoSource, Stats, SimpleMap}
 import reporting.Reporter
+import transform.TreeChecker
 import java.io.{BufferedWriter, OutputStreamWriter}
 import scala.reflect.io.VirtualFile
 
@@ -39,18 +40,19 @@ class Run(comp: Compiler)(implicit ctx: Context) {
       for (phase <- phasesToRun) {
         if (!ctx.reporter.hasErrors) {
           phase.runOn(units)
-          if (ctx.settings.Xprint.value.containsPhase(phase))
-            for (unit <- units)
-              printTree(ctx.fresh.setPhase(phase).setCompilationUnit(unit))
+          def foreachUnit(op: Context => Unit)(implicit ctx: Context): Unit =
+            for (unit <- units) op(ctx.fresh.setPhase(phase.next).setCompilationUnit(unit))
+          if (ctx.settings.Xprint.value.containsPhase(phase)) foreachUnit(printTree)
+          if (ctx.settings.Ycheck.value.containsPhase(phase)) foreachUnit(TreeChecker.check)
         }
       }
     }
   }
 
-  private def printTree(implicit ctx: Context) = {
+  private def printTree(ctx: Context) = {
     val unit = ctx.compilationUnit
     println(s"result of $unit after ${ctx.phase}:")
-    println(unit.tpdTree.show)
+    println(unit.tpdTree.show(ctx))
   }
 
   def compile(sourceCode: String): Unit = {

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

@@ -7,6 +7,7 @@ import util.Positions._, Types._, Contexts._, Constants._, Names._, Flags._
 import SymDenotations._, Symbols._, StdNames._, Annotations._, Trees._
 import CheckTrees._, Denotations._, Decorators._
 import config.Printers._
+import typer.ErrorReporting._
 
 /** Some creators for typed trees */
 object tpd extends Trees.Instance[Type] with TypedTreeInfo {
@@ -400,11 +401,17 @@ object tpd extends Trees.Instance[Type] with TypedTreeInfo {
   }
 
   // convert a numeric with a toXXX method
-  def numericConversion(tree: Tree, numericCls: Symbol)(implicit ctx: Context): Tree = {
+  def primitiveConversion(tree: Tree, numericCls: Symbol)(implicit ctx: Context): Tree = {
     val mname      = ("to" + numericCls.name).toTermName
     val conversion = tree.tpe member mname
-    assert(conversion.symbol.exists, s"$tree => $numericCls")
-    ensureApplied(Select(tree, conversion.symbol.termRef))
+    if (conversion.symbol.exists)
+      ensureApplied(Select(tree, conversion.symbol.termRef))
+    else if (tree.tpe.widen isRef numericCls)
+      tree
+    else {
+      ctx.warning(i"conversion from ${tree.tpe.widen} to ${numericCls.typeRef} will always fail at runtime.")
+      Throw(New(defn.ClassCastExceptionClass.typeRef, Nil)) withPos tree.pos
+    }
   }
 
   def evalOnce(tree: Tree)(within: Tree => Tree)(implicit ctx: Context) = {

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

@@ -97,7 +97,7 @@ class ScalaSettings extends Settings.SettingGroup {
   val overrideVars = BooleanSetting("-Yoverride-vars", "Allow vars to be overridden.")
   val Yhelp = BooleanSetting("-Y", "Print a synopsis of private options.")
   val browse = PhasesSetting("-Ybrowse", "Browse the abstract syntax tree after")
-  val check = PhasesSetting("-Ycheck", "Check the tree at the end of")
+  val Ycheck = PhasesSetting("-Ycheck", "Check the tree at the end of")
   val YcheckTypedTrees = BooleanSetting("-YcheckTypedTrees", "Check all constructured typed trees for type correctness")
   val Yshow = PhasesSetting("-Yshow", "(Requires -Xshow-class or -Xshow-object) Show after")
   val Xcloselim = BooleanSetting("-Yclosure-elim", "Perform closure elimination.")

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

@@ -223,7 +223,6 @@ object Settings {
       setting
     }
 
-
     def BooleanSetting(name: String, descr: String): Setting[Boolean] =
       publish(Setting(name, descr, false))
 

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

@@ -181,6 +181,30 @@ object Contexts {
     protected def searchHistory_= (searchHistory: SearchHistory) = _searchHistory = searchHistory
     def searchHistory: SearchHistory = _searchHistory
 
+    private var phasedCtx: Context = _
+    private var phasedCtxs: Array[Context] = _
+
+
+    /** This context at given phase.
+     *  This method will always return a phase period equal to phaseId, thus will never return squashed phases
+     */
+    final def withPhase(phaseId: PhaseId): Context = {
+      if (this.phaseId == phaseId) this
+      else if (phasedCtx.phaseId == phaseId) phasedCtx
+      else if (phasedCtxs != null && phasedCtxs(phaseId) != null) phasedCtxs(phaseId)
+      else {
+        val ctx1 = fresh.setPhase(phaseId)
+        if (phasedCtx eq this) phasedCtx = ctx1
+        else {
+          if (phasedCtxs == null) phasedCtxs = new Array[Context](base.phases.length)
+          phasedCtxs(phaseId) = ctx1
+        }
+        ctx1
+      }
+    }
+
+    final def withPhase(phase: Phase): Context =
+      withPhase(phase.id)
   /** If -Ydebug is on, the top of the stack trace where this context
      *  was created, otherwise `null`.
      */
@@ -266,29 +290,23 @@ object Contexts {
     }
     */
 
-    /** A fresh clone of this context. */
-    def fresh: FreshContext = {
-      val newctx: Context = super.clone.asInstanceOf[FreshContext]
-      newctx.outer = this
-      newctx.implicitsCache = null
-      newctx.setCreationTrace()
-        // Dotty deviation: Scala2x allows access to private members implicitCache and setCreationTrace
-        // even from a subclass prefix. Dotty (and Java) do not. It's confirmed as a bug in Scala2x.
-      newctx.asInstanceOf[FreshContext]
+    protected def init(outer: Context): this.type = {
+      this.outer = outer
+      this.implicitsCache = null
+      this.phasedCtx = this
+      this.phasedCtxs = null
+      setCreationTrace()
+      this
     }
+    /** A fresh clone of this context. */
+    def fresh: FreshContext = clone.asInstanceOf[FreshContext].init(this)
+
+    final def withOwner(owner: Symbol): Context =
+      if (owner ne this.owner) fresh.setOwner(owner) else this
 
     final def withMode(mode: Mode): Context =
       if (mode != this.mode) fresh.setMode(mode) else this
 
-    /**
-     * This method will always return a phase period equal to phaseId, thus will never return squashed phases
-     */
-    final def withPhase(phaseId: PhaseId): Context =
-      if (this.phaseId == phaseId) this else fresh.setPhase(phaseId)
-    final def withPhase(phase: Phase): Context =
-      if (this.period == phase.period) this else fresh.setPhase(phase)
-
-
     final def addMode(mode: Mode): Context = withMode(this.mode | mode)
     final def maskMode(mode: Mode): Context = withMode(this.mode & mode)
     final def retractMode(mode: Mode): Context = withMode(this.mode &~ mode)
@@ -313,15 +331,15 @@ object Contexts {
     def setPeriod(period: Period): this.type = { this.period = period; this }
     def setMode(mode: Mode): this.type = { this.mode = mode; this }
     def setTyperState(typerState: TyperState): this.type = { this.typerState = typerState; this }
-    def clearTyperState: this.type = setTyperState(typerState.fresh(isCommittable = true))
+    def setNewTyperState: this.type = setTyperState(typerState.fresh(isCommittable = true))
     def setExploreTyperState: this.type = setTyperState(typerState.fresh(isCommittable = false))
     def setPrinterFn(printer: Context => Printer): this.type = { this.printerFn = printer; this }
     def setOwner(owner: Symbol): this.type = { assert(owner != NoSymbol); this.owner = owner; this }
     def setSettings(sstate: SettingsState): this.type = { this.sstate = sstate; this }
     def setCompilationUnit(compilationUnit: CompilationUnit): this.type = { this.compilationUnit = compilationUnit; this }
     def setTree(tree: Tree[_ >: Untyped]): this.type = { this.tree = tree; this }
     def setScope(scope: Scope): this.type = { this.scope = scope; this }
-    def clearScope: this.type = { this.scope = newScope; this }
+    def setNewScope: this.type = { this.scope = newScope; this }
     def setTypeAssigner(typeAssigner: TypeAssigner): this.type = { this.typeAssigner = typeAssigner; this }
     def setTyper(typer: Typer): this.type = { this.scope = typer.scope; setTypeAssigner(typer) }
     def setImportInfo(importInfo: ImportInfo): this.type = { this.importInfo = importInfo; this }

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

@@ -6,6 +6,7 @@ import Symbols._
 import Contexts._, Names._, Phases._, printing.Texts._, printing.Printer
 import util.Positions.Position, util.SourcePosition
 import collection.mutable.ListBuffer
+import dotty.tools.dotc.transform.TreeTransforms._
 import scala.language.implicitConversions
 
 /** This object provides useful implicit decorators for types defined elsewhere */
@@ -127,8 +128,10 @@ object Decorators {
    *  one of the names in the list of strings.
    */
   implicit class PhaseListDecorator(val names: List[String]) extends AnyVal {
-    def containsPhase(phase: Phase) =
-      names exists (phase.name.startsWith)
+    def containsPhase(phase: Phase): Boolean = phase  match {
+      case phase: TreeTransformer => phase.transformations.exists(containsPhase)
+      case _ => names exists (phase.name.startsWith)
+    }
   }
 
   implicit def sourcePos(pos: Position)(implicit ctx: Context): SourcePosition =

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

@@ -103,8 +103,8 @@ class Definitions {
     lazy val Object_!= = newMethod(ObjectClass, nme.NE, methOfAny(BooleanType), Final)
     lazy val Object_eq = newMethod(ObjectClass, nme.eq, methOfAnyRef(BooleanType), Final)
     lazy val Object_ne = newMethod(ObjectClass, nme.ne, methOfAnyRef(BooleanType), Final)
-    lazy val Object_isInstanceOf = newT1EmptyParamsMethod(ObjectClass, nme.isInstanceOf_Ob, _ => BooleanType, Final | Synthetic)
-    lazy val Object_asInstanceOf = newT1EmptyParamsMethod(ObjectClass, nme.asInstanceOf_Ob, PolyParam(_, 0), Final | Synthetic)
+    lazy val Object_isInstanceOf = newT1ParameterlessMethod(ObjectClass, nme.isInstanceOf_Ob, _ => BooleanType, Final | Synthetic)
+    lazy val Object_asInstanceOf = newT1ParameterlessMethod(ObjectClass, nme.asInstanceOf_Ob, PolyParam(_, 0), Final | Synthetic)
     lazy val Object_synchronized = newPolyMethod(ObjectClass, nme.synchronized_, 1,
         pt => MethodType(List(PolyParam(pt, 0)), PolyParam(pt, 0)), Final)
 
@@ -218,6 +218,7 @@ class Definitions {
   lazy val OptionClass                  = ctx.requiredClass("scala.Option")
   lazy val BoxedNumberClass             = ctx.requiredClass("java.lang.Number")
   lazy val ThrowableClass               = ctx.requiredClass("java.lang.Throwable")
+  lazy val ClassCastExceptionClass      = ctx.requiredClass("java.lang.ClassCastException")
   lazy val JavaSerializableClass        = ctx.requiredClass("java.lang.Serializable")
   lazy val ComparableClass              = ctx.requiredClass("java.lang.Comparable")
   lazy val ProductClass                 = ctx.requiredClass("scala.Product")

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

@@ -107,11 +107,11 @@ object Phases {
                 postTyperEmmited = true
                 new PostTyperTransformer {
                   override def name: String = transformations.map(_.name).mkString("TreeTransform:{", ", ", "}")
-                  override protected def transformations: Array[TreeTransform] = transforms.toArray
+                  override def transformations: Array[TreeTransform] = transforms.toArray
                 }
               } else new TreeTransformer {
                 override def name: String = transformations.map(_.name).mkString("TreeTransform:{", ", ", "}")
-                override protected def transformations: Array[TreeTransform] = transforms.toArray
+                override def transformations: Array[TreeTransform] = transforms.toArray
               }
             squashedPhases += block
             block.init(this, phasess(i).head.id, phasess(i).last.id)

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

@@ -147,7 +147,7 @@ object SymDenotations {
       myFlags |= Touched
 
       // completions.println(s"completing ${this.debugString}")
-      try completer.complete(this)
+      try completer.complete(this)(ctx.withPhase(validFor.firstPhaseId))
       catch {
         case ex: CyclicReference =>
           completions.println(s"error while completing ${this.debugString}")

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

@@ -39,6 +39,8 @@ import TypeApplications._
 /** A decorator that provides methods for modeling type application */
 class TypeApplications(val self: Type) extends AnyVal {
 
+  def canHaveTypeParams(implicit ctx: Context) = !ctx.erasedTypes || self.isRef(defn.ArrayClass)
+
   /** The type parameters of this type are:
    *  For a ClassInfo type, the type parameters of its class.
    *  For a typeref referring to a class, the type parameters of the class.
@@ -128,7 +130,7 @@ class TypeApplications(val self: Type) extends AnyVal {
         defn.hkTrait(args map alwaysZero).typeParams
       }
 
-    if (args.isEmpty) self
+    if (args.isEmpty || !canHaveTypeParams) self
     else self match {
       case tp: TypeRef =>
         val tsym = tp.symbol
@@ -228,8 +230,11 @@ class TypeApplications(val self: Type) extends AnyVal {
    *  `from` and `to` must be static classes, both with one type parameter, and the same variance.
    */
   def translateParameterized(from: ClassSymbol, to: ClassSymbol)(implicit ctx: Context): Type =
-    if (self derivesFrom from)
-      RefinedType(to.typeRef, to.typeParams.head.name, self.member(from.typeParams.head.name).info)
+    if (self.derivesFrom(from))
+      if (canHaveTypeParams)
+        RefinedType(to.typeRef, to.typeParams.head.name, self.member(from.typeParams.head.name).info)
+      else
+        to.typeRef
     else self
 
   /** If this is an encoding of a (partially) applied type, return its arguments,

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

@@ -1039,6 +1039,7 @@ object Types {
       }
       lastDenotation = d
       lastSymbol = d.symbol
+      checkedPeriod = ctx.period
       d
     }
 

src/dotty/tools/dotc/core/transform/Erasure.scala

@@ -61,16 +61,11 @@ object Erasure {
    */
   def transformInfo(sym: Symbol, tp: Type)(implicit ctx: Context): Type = {
     val erase = erasureFn(sym is JavaDefined, isSemi = true, sym.isConstructor, wildcardOK = false)
-    if ((sym eq defn.Object_asInstanceOf) || sym.isType && (sym.owner eq defn.ArrayClass))
-      sym.info
-    else if ((sym eq defn.Object_isInstanceOf) || (sym eq defn.ArrayClass.primaryConstructor)) {
-      val tp @ PolyType(pnames) = sym.info
-      tp.derivedPolyType(pnames, TypeBounds.empty :: Nil, erase(tp.resultType))
-    }
-    else if (sym.isAbstractType)
-      TypeAlias(WildcardType)
-    else
-      erase(tp)
+    if ((sym eq defn.Object_asInstanceOf) ||
+        (sym eq defn.Object_isInstanceOf) ||
+        (sym.owner eq defn.ArrayClass) && (sym.isType || sym.isConstructor)) sym.info
+    else if (sym.isAbstractType) TypeAlias(WildcardType)
+    else erase(tp)
   }
 
   def isUnboundedGeneric(tp: Type)(implicit ctx: Context) = !(
@@ -120,7 +115,7 @@ class Erasure(isJava: Boolean, isSemi: Boolean, isConstructor: Boolean, wildcard
     case tp: TypeRef =>
       val sym = tp.symbol
       if (!sym.isClass)
-        if (sym.owner eq defn.ArrayClass) tp else this(tp.info)
+        if (sym.exists && (sym.owner eq defn.ArrayClass)) tp else this(tp.info) //!!!!
       else if (sym.isDerivedValueClass) eraseDerivedValueClassRef(tp)
       else eraseNormalClassRef(tp)
     case tp: RefinedType =>