Restructure Try node.

src/dotty/tools/dotc/Run.scala

@@ -3,6 +3,7 @@ package dotc
 
 import core._
 import Contexts._, Periods._, Symbols._, Phases._, Decorators._
+import dotty.tools.dotc.transform.TreeTransforms.TreeTransformer
 import io.PlainFile
 import util.{SourceFile, NoSource, Stats, SimpleMap}
 import reporting.Reporter
@@ -60,7 +61,10 @@ class Run(comp: Compiler)(implicit ctx: Context) {
 
   private def printTree(ctx: Context) = {
     val unit = ctx.compilationUnit
-    println(s"result of $unit after ${ctx.phase.prev}:")
+    val prevPhase = ctx.phase.prev // can be a mini-phase
+    val squahsedPhase = ctx.squashed(prevPhase)
+
+    println(s"result of $unit after ${squahsedPhase}:")
     println(unit.tpdTree.show(ctx))
   }
 

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

@@ -817,6 +817,16 @@ object desugar {
       case PatDef(mods, pats, tpt, rhs) =>
         val pats1 = if (tpt.isEmpty) pats else pats map (Typed(_, tpt))
         flatTree(pats1 map (makePatDef(mods, _, rhs)))
+      case ParsedTry(body, handler, finalizer) =>
+        handler match {
+          case Match(EmptyTree, cases) => Try(body, cases, finalizer)
+          case EmptyTree => Try(body, Nil, finalizer)
+          case _ =>
+            Try(body,
+              List(CaseDef(Ident(nme.DEFAULT_EXCEPTION_NAME), EmptyTree, Apply(handler, Ident(nme.DEFAULT_EXCEPTION_NAME)))),
+              finalizer)
+        }
+
     }
   }.withPos(tree.pos)
 

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

@@ -611,7 +611,7 @@ object Trees {
    *
    *    Match(EmptyTree, <case x: Throwable => $anonfun(x)>)
    */
-  case class Try[-T >: Untyped] private[ast] (expr: Tree[T], handler: Tree[T], finalizer: Tree[T])
+  case class Try[-T >: Untyped] private[ast] (expr: Tree[T], cases: List[CaseDef[T]], finalizer: Tree[T])
     extends TermTree[T] {
     type ThisTree[-T >: Untyped] = Try[T]
   }
@@ -1024,9 +1024,9 @@ object Trees {
         case tree: Return if (expr eq tree.expr) && (from eq tree.from) => tree
         case _ => finalize(tree, untpd.Return(expr, from))
       }
-      def Try(tree: Tree)(expr: Tree, handler: Tree, finalizer: Tree)(implicit ctx: Context): Try = tree match {
-        case tree: Try if (expr eq tree.expr) && (handler eq tree.handler) && (finalizer eq tree.finalizer) => tree
-        case _ => finalize(tree, untpd.Try(expr, handler, finalizer))
+      def Try(tree: Tree)(expr: Tree, cases: List[CaseDef], finalizer: Tree)(implicit ctx: Context): Try = tree match {
+        case tree: Try if (expr eq tree.expr) && (cases eq tree.cases) && (finalizer eq tree.finalizer) => tree
+        case _ => finalize(tree, untpd.Try(expr, cases, finalizer))
       }
       def Throw(tree: Tree)(expr: Tree)(implicit ctx: Context): Throw = tree match {
         case tree: Throw if (expr eq tree.expr) => tree
@@ -1128,8 +1128,8 @@ object Trees {
         Closure(tree: Tree)(env, meth, tpt)
       def CaseDef(tree: CaseDef)(pat: Tree = tree.pat, guard: Tree = tree.guard, body: Tree = tree.body)(implicit ctx: Context): CaseDef =
         CaseDef(tree: Tree)(pat, guard, body)
-      def Try(tree: Try)(expr: Tree = tree.expr, handler: Tree = tree.handler, finalizer: Tree = tree.finalizer)(implicit ctx: Context): Try =
-        Try(tree: Tree)(expr, handler, finalizer)
+      def Try(tree: Try)(expr: Tree = tree.expr, cases: List[CaseDef] = tree.cases, finalizer: Tree = tree.finalizer)(implicit ctx: Context): Try =
+        Try(tree: Tree)(expr, cases, finalizer)
       def UnApply(tree: UnApply)(fun: Tree = tree.fun, implicits: List[Tree] = tree.implicits, patterns: List[Tree] = tree.patterns): UnApply =
         UnApply(tree: Tree)(fun, implicits, patterns)
       def ValDef(tree: ValDef)(mods: Modifiers = tree.mods, name: TermName = tree.name, tpt: Tree = tree.tpt, rhs: Tree = tree.rhs): ValDef =
@@ -1181,8 +1181,8 @@ object Trees {
           cpy.CaseDef(tree)(transform(pat), transform(guard), transform(body))
         case Return(expr, from) =>
           cpy.Return(tree)(transform(expr), transformSub(from))
-        case Try(block, handler, finalizer) =>
-          cpy.Try(tree)(transform(block), transform(handler), transform(finalizer))
+        case Try(block, cases, finalizer) =>
+          cpy.Try(tree)(transform(block), transformSub(cases), transform(finalizer))
         case Throw(expr) =>
           cpy.Throw(tree)(transform(expr))
         case SeqLiteral(elems) =>

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

@@ -113,8 +113,8 @@ object tpd extends Trees.Instance[Type] with TypedTreeInfo {
   def Return(expr: Tree, from: Tree)(implicit ctx: Context): Return =
     ta.assignType(untpd.Return(expr, from))
 
-  def Try(block: Tree, handler: Tree, finalizer: Tree)(implicit ctx: Context): Try =
-    ta.assignType(untpd.Try(block, handler, finalizer), block, handler)
+  def Try(block: Tree, cases: List[CaseDef], finalizer: Tree)(implicit ctx: Context): Try =
+    ta.assignType(untpd.Try(block, cases, finalizer), block, cases)
 
   def Throw(expr: Tree)(implicit ctx: Context): Throw =
     ta.assignType(untpd.Throw(expr))
@@ -457,11 +457,11 @@ object tpd extends Trees.Instance[Type] with TypedTreeInfo {
     override def Return(tree: Tree)(expr: Tree, from: Tree)(implicit ctx: Context): Return =
       ta.assignType(untpd.cpy.Return(tree)(expr, from))
 
-    override def Try(tree: Tree)(expr: Tree, handler: Tree, finalizer: Tree)(implicit ctx: Context): Try = {
-      val tree1 = untpd.cpy.Try(tree)(expr, handler, finalizer)
+    override def Try(tree: Tree)(expr: Tree, cases: List[CaseDef], finalizer: Tree)(implicit ctx: Context): Try = {
+      val tree1 = untpd.cpy.Try(tree)(expr, cases, finalizer)
       tree match {
-        case tree: Try if (expr.tpe eq tree.expr.tpe) && (handler.tpe eq tree.handler.tpe) => tree1.withTypeUnchecked(tree.tpe)
-        case _ => ta.assignType(tree1, expr, handler)
+        case tree: Try if (expr.tpe eq tree.expr.tpe) && (sameTypes(cases, tree.cases)) => tree1.withTypeUnchecked(tree.tpe)
+        case _ => ta.assignType(tree1, expr, cases)
       }
     }
 
@@ -490,8 +490,8 @@ object tpd extends Trees.Instance[Type] with TypedTreeInfo {
       Closure(tree: Tree)(env, meth, tpt)
     override def CaseDef(tree: CaseDef)(pat: Tree = tree.pat, guard: Tree = tree.guard, body: Tree = tree.body)(implicit ctx: Context): CaseDef =
       CaseDef(tree: Tree)(pat, guard, body)
-    override def Try(tree: Try)(expr: Tree = tree.expr, handler: Tree = tree.handler, finalizer: Tree = tree.finalizer)(implicit ctx: Context): Try =
-      Try(tree: Tree)(expr, handler, finalizer)
+    override def Try(tree: Try)(expr: Tree = tree.expr, cases: List[CaseDef] = tree.cases, finalizer: Tree = tree.finalizer)(implicit ctx: Context): Try =
+      Try(tree: Tree)(expr, cases, finalizer)
   }
 
   implicit class TreeOps[ThisTree <: tpd.Tree](val tree: ThisTree) extends AnyVal {

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

@@ -32,6 +32,8 @@ object untpd extends Trees.Instance[Untyped] with UntypedTreeInfo {
     def withName(name: Name)(implicit ctx: Context) = cpy.ModuleDef(this)(mods, name.toTermName, impl)
   }
 
+  case class ParsedTry(expr: Tree, handler: Tree, finalizer: Tree) extends TermTree
+
   case class SymbolLit(str: String) extends TermTree
   case class InterpolatedString(id: TermName, strings: List[Literal], elems: List[Tree]) extends TermTree
   case class Function(args: List[Tree], body: Tree) extends Tree {
@@ -123,7 +125,7 @@ object untpd extends Trees.Instance[Untyped] with UntypedTreeInfo {
   def Match(selector: Tree, cases: List[CaseDef]): Match = new Match(selector, cases)
   def CaseDef(pat: Tree, guard: Tree, body: Tree): CaseDef = new CaseDef(pat, guard, body)
   def Return(expr: Tree, from: Tree): Return = new Return(expr, from)
-  def Try(expr: Tree, handler: Tree, finalizer: Tree): Try = new Try(expr, handler, finalizer)
+  def Try(expr: Tree, cases: List[CaseDef], finalizer: Tree): Try = new Try(expr, cases, finalizer)
   def Throw(expr: Tree): Throw = new Throw(expr)
   def SeqLiteral(elems: List[Tree]): SeqLiteral = new SeqLiteral(elems)
   def JavaSeqLiteral(elems: List[Tree]): JavaSeqLiteral = new JavaSeqLiteral(elems)

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

@@ -472,6 +472,10 @@ object Contexts {
 
     /** The standard definitions */
     val definitions = new Definitions
+
+    def squashed(p: Phase): Phase = {
+      squashedPhases.find(_.period.containsPhaseId(p.id)).getOrElse(NoPhase)
+    }
   }
 
   /** The essential mutable state of a context base, collected into a common class */

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

@@ -9,7 +9,7 @@ import Denotations._
 import config.Printers._
 import scala.collection.mutable.{ListBuffer, ArrayBuffer}
 import dotty.tools.dotc.transform.TreeTransforms.{TreeTransformer, MiniPhase, TreeTransform}
-import dotty.tools.dotc.transform.{TreeTransforms, ExplicitOuter, Erasure, Flatten, GettersSetters}
+import dotty.tools.dotc.transform._
 import Periods._
 import typer.{FrontEnd, RefChecks}
 import ast.tpd
@@ -167,13 +167,15 @@ object Phases {
     private val typerCache = new PhaseCache(classOf[FrontEnd])
     private val refChecksCache = new PhaseCache(classOf[RefChecks])
     private val erasureCache = new PhaseCache(classOf[Erasure])
+    private val patmatCache = new PhaseCache(classOf[PatternMatcher])
     private val flattenCache = new PhaseCache(classOf[Flatten])
     private val explicitOuterCache = new PhaseCache(classOf[ExplicitOuter])
     private val gettersSettersCache = new PhaseCache(classOf[GettersSetters])
 
     def typerPhase = typerCache.phase
     def refchecksPhase = refChecksCache.phase
     def erasurePhase = erasureCache.phase
+    def patmatPhase = patmatCache.phase
     def flattenPhase = flattenCache.phase
     def explicitOuterPhase = explicitOuterCache.phase
     def gettersSettersPhase = gettersSettersCache.phase

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

@@ -121,6 +121,7 @@ object StdNames {
     val SUPER_PREFIX: N               = "super$"
     val TRAIT_SETTER_PREFIX: N        = "_setter_$"
     val WHILE_PREFIX: N               = "while$"
+    val DEFAULT_EXCEPTION_NAME: N = "ex$"
 
     // value types (and AnyRef) are all used as terms as well
     // as (at least) arguments to the @specialize annotation.

src/dotty/tools/dotc/core/pickling/UnPickler.scala

@@ -1035,7 +1035,7 @@ class UnPickler(bytes: Array[Byte], classRoot: ClassDenotation, moduleClassRoot:
         val block = readTreeRef()
         val finalizer = readTreeRef()
         val catches = until(end, readCaseDefRef)
-        Try(block, Match(EmptyTree, catches), finalizer)
+        Try(block, catches, finalizer)
 
       case THROWtree =>
         Throw(readTreeRef())

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

@@ -914,7 +914,7 @@ object Parsers {
           val finalizer =
             if (handler.isEmpty || in.token == FINALLY) { accept(FINALLY); expr() }
             else EmptyTree
-          Try(body, handler, finalizer)
+          ParsedTry(body, handler, finalizer)
         }
       case THROW =>
         atPos(in.skipToken()) { Throw(expr()) }

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

@@ -141,6 +141,9 @@ class RefinedPrinter(_ctx: Context) extends PlainPrinter(_ctx) {
     super.toText(tp)
   }
 
+  def blockText[T >: Untyped](trees: List[Tree[T]]): Text =
+    "{" ~ toText(trees, "\n") ~ "}"
+
   override def toText[T >: Untyped](tree: Tree[T]): Text = controlled {
 
     def optDotPrefix(name: Name) = optText(name)(_ ~ ".")
@@ -155,8 +158,7 @@ class RefinedPrinter(_ctx: Context) extends PlainPrinter(_ctx) {
     def addVparamssText(txt: Text, vparamss: List[List[ValDef[T]]]): Text =
       (txt /: vparamss)((txt, vparams) => txt ~ "(" ~ toText(vparams, ", ") ~ ")")
 
-    def blockText(trees: List[Tree[T]]): Text =
-      "{" ~ toText(trees, "\n") ~ "}"
+
 
     def caseBlockText(tree: Tree[T]): Text = tree match {
       case Block(stats, expr) => toText(stats :+ expr, "\n")
@@ -261,9 +263,9 @@ class RefinedPrinter(_ctx: Context) extends PlainPrinter(_ctx) {
         "case " ~ toText(pat) ~ optText(guard)(" if " ~ _) ~ " => " ~ caseBlockText(body)
       case Return(expr, from) =>
         changePrec(GlobalPrec) { "return" ~ optText(expr)(" " ~ _) }
-      case Try(expr, handler, finalizer) =>
+      case Try(expr, cases, finalizer) =>
         changePrec(GlobalPrec) {
-          "try " ~ toText(expr) ~ optText(handler)(" catch " ~ _) ~ optText(finalizer)(" finally " ~ _)
+          "try " ~ toText(expr) ~ optText(cases)(" catch " ~ _) ~ optText(finalizer)(" finally " ~ _)
         }
       case Throw(expr) =>
         changePrec(GlobalPrec) {
@@ -461,6 +463,9 @@ class RefinedPrinter(_ctx: Context) extends PlainPrinter(_ctx) {
   def optText[T >: Untyped](tree: Tree[T])(encl: Text => Text): Text =
     if (tree.isEmpty) "" else encl(toText(tree))
 
+  def optText[T >: Untyped](tree: List[Tree[T]])(encl: Text => Text): Text =
+    if (tree.exists(!_.isEmpty)) "" else encl(blockText(tree))
+
   override protected def polyParamName(name: TypeName): TypeName =
     name.unexpandedName()
 

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

@@ -111,10 +111,10 @@ object Erasure extends TypeTestsCasts{
   object Boxing {
 
     def isUnbox(sym: Symbol)(implicit ctx: Context) =
-      sym.name == nme.unbox && (defn.ScalaBoxedClasses contains sym.owner)
+      sym.name == nme.unbox && (defn.ScalaBoxedClasses contains sym.owner.linkedClass)
 
     def isBox(sym: Symbol)(implicit ctx: Context) =
-      sym.name == nme.box && (defn.ScalaValueClasses contains sym.owner)
+      sym.name == nme.box && (defn.ScalaValueClasses contains sym.owner.linkedClass)
 
     def boxMethod(cls: ClassSymbol)(implicit ctx: Context) =
       cls.linkedClass.info.member(nme.box).symbol

src/dotty/tools/dotc/transform/LazyVals.scala

@@ -217,18 +217,15 @@ class LazyValsTransform extends MiniPhaseTransform with IdentityDenotTransformer
       val compute = {
         val handlerSymbol = ctx.newSymbol(methodSymbol, "$anonfun".toTermName, Flags.Synthetic,
           MethodType(List("x$1".toTermName), List(defn.ThrowableType), defn.IntType))
-
-        val handler = Closure(handlerSymbol, {
-          args =>
-            val exception = args.head.head
-            val complete = setFlagState.appliedTo(thiz, offset, initState, Literal(Constant(ord)))
-            Block(List(complete), Throw(exception))
-        })
+        val caseSymbol = ctx.newSymbol(methodSymbol, nme.DEFAULT_EXCEPTION_NAME, Flags.Synthetic, defn.ThrowableType)
+        val complete = setFlagState.appliedTo(thiz, offset, initState, Literal(Constant(ord)))
+        val handler = CaseDef(Bind(caseSymbol, ref(caseSymbol)), EmptyTree,
+          Block(List(complete), Throw(ref(caseSymbol))
+        ))
 
         val compute = Assign(ref(resultSymbol), rhs)
-        val tr = Try(compute, handler, EmptyTree)
+        val tr = Try(compute, List(handler), EmptyTree)
         val assign = Assign(ref(target), ref(resultSymbol))
-        val complete = setFlagState.appliedTo(thiz, offset, computedState, Literal(Constant(ord)))
         val noRetry = Assign(ref(retrySymbol), Literal(Constants.Constant(false)))
         val body = If(casFlag.appliedTo(thiz, offset, ref(flagSymbol), computeState, Literal(Constant(ord))),
           Block(tr :: assign :: complete :: noRetry :: Nil, Literal(Constant(()))),

src/dotty/tools/dotc/transform/PatternMatcher.scala

@@ -50,6 +50,7 @@ class PatternMatcher extends MiniPhaseTransform with DenotTransformer {thisTrans
 
   override def transformMatch(tree: Match)(implicit ctx: Context, info: TransformerInfo): Tree = {
     val translated = new Translator()(ctx).translator.translateMatch(tree)
+
     translated.ensureConforms(tree.tpe)
   }
 
@@ -778,10 +779,11 @@ class PatternMatcher extends MiniPhaseTransform with DenotTransformer {thisTrans
       // is this purely a type test, e.g. no outer check, no equality tests (used in switch emission)
       //def isPureTypeTest = renderCondition(pureTypeTestChecker)
 
-      def impliesBinderNonNull(binder: Symbol):Boolean =
+      def impliesBinderNonNull(binder: Symbol): Boolean =
       // @odersky: scalac is able to infer in this method that nonNullImpliedByTestChecker.Result,
       // dotty instead infers type projection TreeMakers.this.TypeTestTreeMaker.TypeTestCondStrategy#Result
       // which in turn doesn't typecheck in this method. Can you please explain why?
+      // dotty deviation
         renderCondition(nonNullImpliedByTestChecker(binder)).asInstanceOf[Boolean]
 
       override def toString = "TT"+((expectedTp, testedBinder.name, nextBinderTp))
@@ -1136,7 +1138,11 @@ class PatternMatcher extends MiniPhaseTransform with DenotTransformer {thisTrans
       *   this could probably optimized... (but note that the matchStrategy must be solved for each nested patternmatch)
       */
     def translateMatch(match_ : Match): Tree = {
-      val Match(selector, cases) = match_
+      val Match(sel, cases) = match_
+
+      val selectorTp = elimAnonymousClass(sel.tpe.widen/*withoutAnnotations*/)
+
+      val selectorSym = freshSym(sel.pos, selectorTp, "selector")
 
       val (nonSyntheticCases, defaultOverride) = cases match {
         case init :+ last if isSyntheticDefaultCase(last) => (init, Some(((scrut: Symbol) => last.body)))
@@ -1155,23 +1161,20 @@ class PatternMatcher extends MiniPhaseTransform with DenotTransformer {thisTrans
 
       //val start = if (Statistics.canEnable) Statistics.startTimer(patmatNanos) else null
 
-      val selectorTp = elimAnonymousClass(selector.tpe.widen/*withoutAnnotations*/)
-
       // when one of the internal cps-type-state annotations is present, strip all CPS annotations
       ///val origPt  = removeCPSFromPt(match_.tpe)
       // relevant test cases: pos/existentials-harmful.scala, pos/gadt-gilles.scala, pos/t2683.scala, pos/virtpatmat_exist4.scala
       // pt is the skolemized version
       val pt = match_.tpe.widen //repeatedToSeq(origPt)
 
       // val packedPt = repeatedToSeq(typer.packedType(match_, context.owner))
-      val selectorSym = freshSym(selector.pos, selectorTp, "selector")
       selectorSym.setFlag(Flags.SyntheticCase)
 
       // pt = Any* occurs when compiling test/files/pos/annotDepMethType.scala  with -Xexperimental
-      val combined = combineCases(selector, selectorSym, nonSyntheticCases map translateCase(selectorSym, pt), pt, ctx.owner, defaultOverride)
+      val combined = combineCases(sel, selectorSym, nonSyntheticCases map translateCase(selectorSym, pt), pt, ctx.owner, defaultOverride)
 
       // if (Statistics.canEnable) Statistics.stopTimer(patmatNanos, start)
-      Block(List(ValDef(selectorSym,selector)), combined)
+      Block(List(ValDef(selectorSym, sel)), combined)
     }
 
     // return list of typed CaseDefs that are supported by the backend (typed/bind/wildcard)

src/dotty/tools/dotc/transform/TailRec.scala

@@ -156,9 +156,8 @@ class TailRec extends MiniPhaseTransform with DenotTransformer with FullParamete
     def noTailTransform(tree: Tree)(implicit c: Context): Tree =
       transform(tree, noTailContext)
 
-
-    def noTailTransforms(trees: List[Tree])(implicit c: Context) =
-      trees map (noTailTransform)
+    def noTailTransforms[Tr <: Tree](trees: List[Tr])(implicit c: Context): List[Tr] =
+      trees.map(noTailTransform).asInstanceOf[List[Tr]]
 
     override def transform(tree: Tree)(implicit c: Context): Tree = {
       /* A possibly polymorphic apply to be considered for tail call transformation. */
@@ -232,26 +231,18 @@ class TailRec extends MiniPhaseTransform with DenotTransformer with FullParamete
       }
 
       def rewriteTry(tree: Try): Try = {
-        def transformHandlers(t: Tree): Tree = {
-          t match {
-            case Block(List((d: DefDef)), cl@Closure(Nil, _, EmptyTree)) =>
-              val newDef = cpy.DefDef(d)(rhs = transform(d.rhs))
-              Block(List(newDef), cl)
-            case _ => assert(false, s"failed to deconstruct try handler ${t.show}"); ???
-          }
-        }
         if (tree.finalizer eq EmptyTree) {
           // SI-1672 Catches are in tail position when there is no finalizer
           tpd.cpy.Try(tree)(
             noTailTransform(tree.expr),
-            transformHandlers(tree.handler),
+            transformSub(tree.cases),
             EmptyTree
           )
         }
         else {
           tpd.cpy.Try(tree)(
             noTailTransform(tree.expr),
-            noTailTransform(tree.handler),
+            noTailTransforms(tree.cases),
             noTailTransform(tree.finalizer)
           )
         }