Get rid of ExceptionHandlerSel.

It's not used anymore as superseded by previous commit.

Author: DarkDimius

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

@@ -804,7 +804,7 @@ object Trees {
     type ThisTree[-T >: Untyped] = Thicket[T]
     override def isEmpty: Boolean = trees.isEmpty
     override def toList: List[Tree[T]] = flatten(trees)
-    override def toString = if(this eq theExceptionHandlerSel) "ExceptionSel" else if (isEmpty) "EmptyTree" else "Thicket(" + trees.mkString(", ") + ")"
+    override def toString = if (isEmpty) "EmptyTree" else "Thicket(" + trees.mkString(", ") + ")"
     override def withPos(pos: Position): this.type = {
       val newTrees = trees.map(_.withPos(pos))
       new Thicket[T](newTrees).asInstanceOf[this.type]
@@ -818,11 +818,9 @@ object Trees {
 
   val theEmptyTree: Thicket[Type] = Thicket(Nil)
   val theEmptyValDef = new EmptyValDef[Type]
-  val theExceptionHandlerSel: Thicket[Type] = Thicket(Nil)
 
   def genericEmptyValDef[T >: Untyped]: ValDef[T] = theEmptyValDef.asInstanceOf[ValDef[T]]
   def genericEmptyTree[T >: Untyped]: Thicket[T] = theEmptyTree.asInstanceOf[Thicket[T]]
-  def genericExceptionHandlerSel[T >: Untyped]: Thicket[T] = theExceptionHandlerSel.asInstanceOf[Thicket[T]]
 
   def flatten[T >: Untyped](trees: List[Tree[T]]): List[Tree[T]] = {
     var buf: ListBuffer[Tree[T]] = null
@@ -913,7 +911,6 @@ object Trees {
     type Thicket = Trees.Thicket[T]
 
     val EmptyTree: Thicket = genericEmptyTree
-    val ExceptionHandlerSel: Thicket = genericExceptionHandlerSel // selector used in exception hanlder of Try nodes
     val EmptyValDef: ValDef = genericEmptyValDef
 
     // ----- Auxiliary creation methods ------------------

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

@@ -1139,9 +1139,7 @@ class PatternMatcher extends MiniPhaseTransform with DenotTransformer {thisTrans
 
       val selectorTp = elimAnonymousClass(sel.tpe.widen/*withoutAnnotations*/)
 
-      val selectorSym =
-        if (sel ne ExceptionHandlerSel) freshSym(sel.pos, selectorTp, "selector")
-        else freshSym(match_.pos, defn.ThrowableType, "ex")
+      val selectorSym = freshSym(sel.pos, selectorTp, "selector")
 
       val (nonSyntheticCases, defaultOverride) = cases match {
         case init :+ last if isSyntheticDefaultCase(last) => (init, Some(((scrut: Symbol) => last.body)))

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

@@ -231,17 +231,6 @@ 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 Match(Typed(ExceptionHandlerSel, _), _) =>
-              transform(t)
-            case _: Ident|_: Apply| _: TypeApply => t // handler is an external function
-            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)(

src/dotty/tools/dotc/typer/Typer.scala

@@ -345,8 +345,6 @@ class Typer extends Namer with TypeAssigner with Applications with Implicits wit
       assignType(cpy.Typed(tree)(expr1, tpt1), tpt1)
     }
     tree.expr match {
-      case ExceptionHandlerSel if (tree.tpt.tpe == defn.ThrowableType) =>
-        tree withType defn.ThrowableType
       case id: untpd.Ident if (ctx.mode is Mode.Pattern) && isVarPattern(id) =>
         if (id.name == nme.WILDCARD) regularTyped(isWildcard = true)
         else {