Remove tpt from Hole (#17455)

Now the type is kept in the `Hole` node.

Author: nicolasstucki

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

@@ -746,6 +746,19 @@ object Trees {
       s"TypeTree${if (hasType) s"[$typeOpt]" else ""}"
   }
 
+  /** Tree that replaces a level 1 splices in pickled (level 0) quotes.
+   *  It is only used when picking quotes (will never be in a TASTy file).
+   *
+   *  @param isTerm If this hole is a term, otherwise it is a type hole.
+   *  @param idx The index of the hole in it's enclosing level 0 quote.
+   *  @param args The arguments of the splice to compute its content
+   *  @param content Lambda that computes the content of the hole. This tree is empty when in a quote pickle.
+   */
+  case class Hole[+T <: Untyped](override val isTerm: Boolean, idx: Int, args: List[Tree[T]], content: Tree[T])(implicit @constructorOnly src: SourceFile) extends Tree[T] {
+    type ThisTree[+T <: Untyped] <: Hole[T]
+    override def isType: Boolean = !isTerm
+  }
+
   /** A type tree whose type is inferred. These trees appear in two contexts
    *    - as an argument of a TypeApply. In that case its type is always a TypeVar
    *    - as a (result-)type of an inferred ValDef or DefDef.
@@ -1035,20 +1048,6 @@ object Trees {
   def genericEmptyValDef[T <: Untyped]: ValDef[T]       = theEmptyValDef.asInstanceOf[ValDef[T]]
   def genericEmptyTree[T <: Untyped]: Thicket[T]        = theEmptyTree.asInstanceOf[Thicket[T]]
 
-  /** Tree that replaces a level 1 splices in pickled (level 0) quotes.
-   *  It is only used when picking quotes (will never be in a TASTy file).
-   *
-   *  @param isTerm If this hole is a term, otherwise it is a type hole.
-   *  @param idx The index of the hole in it's enclosing level 0 quote.
-   *  @param args The arguments of the splice to compute its content
-   *  @param content Lambda that computes the content of the hole. This tree is empty when in a quote pickle.
-   *  @param tpt Type of the hole
-   */
-  case class Hole[+T <: Untyped](override val isTerm: Boolean, idx: Int, args: List[Tree[T]], content: Tree[T], tpt: Tree[T])(implicit @constructorOnly src: SourceFile) extends Tree[T] {
-    type ThisTree[+T <: Untyped] <: Hole[T]
-    override def isType: Boolean = !isTerm
-  }
-
   def flatten[T <: Untyped](trees: List[Tree[T]]): List[Tree[T]] = {
     def recur(buf: ListBuffer[Tree[T]] | Null, remaining: List[Tree[T]]): ListBuffer[Tree[T]] | Null =
       remaining match {
@@ -1406,9 +1405,9 @@ object Trees {
         case tree: Thicket if (trees eq tree.trees) => tree
         case _ => finalize(tree, untpd.Thicket(trees)(sourceFile(tree)))
       }
-      def Hole(tree: Tree)(isTerm: Boolean, idx: Int, args: List[Tree], content: Tree, tpt: Tree)(using Context): Hole = tree match {
+      def Hole(tree: Tree)(isTerm: Boolean, idx: Int, args: List[Tree], content: Tree)(using Context): Hole = tree match {
         case tree: Hole if isTerm == tree.isTerm && idx == tree.idx && args.eq(tree.args) && content.eq(tree.content) && content.eq(tree.content) => tree
-        case _ => finalize(tree, untpd.Hole(isTerm, idx, args, content, tpt)(sourceFile(tree)))
+        case _ => finalize(tree, untpd.Hole(isTerm, idx, args, content)(sourceFile(tree)))
       }
 
       // Copier methods with default arguments; these demand that the original tree
@@ -1431,8 +1430,8 @@ object Trees {
         TypeDef(tree: Tree)(name, rhs)
       def Template(tree: Template)(using Context)(constr: DefDef = tree.constr, parents: List[Tree] = tree.parents, derived: List[untpd.Tree] = tree.derived, self: ValDef = tree.self, body: LazyTreeList = tree.unforcedBody): Template =
         Template(tree: Tree)(constr, parents, derived, self, body)
-      def Hole(tree: Hole)(isTerm: Boolean = tree.isTerm, idx: Int = tree.idx, args: List[Tree] = tree.args, content: Tree = tree.content, tpt: Tree = tree.tpt)(using Context): Hole =
-        Hole(tree: Tree)(isTerm, idx, args, content, tpt)
+      def Hole(tree: Hole)(isTerm: Boolean = tree.isTerm, idx: Int = tree.idx, args: List[Tree] = tree.args, content: Tree = tree.content)(using Context): Hole =
+        Hole(tree: Tree)(isTerm, idx, args, content)
 
     }
 
@@ -1567,8 +1566,8 @@ object Trees {
               cpy.Quote(tree)(transform(body)(using quoteContext), transform(tags))
             case tree @ Splice(expr) =>
               cpy.Splice(tree)(transform(expr)(using spliceContext))
-            case tree @ Hole(isTerm, idx, args, content, tpt) =>
-              cpy.Hole(tree)(isTerm, idx, transform(args), transform(content), transform(tpt))
+            case tree @ Hole(isTerm, idx, args, content) =>
+              cpy.Hole(tree)(isTerm, idx, transform(args), transform(content))
             case _ =>
               transformMoreCases(tree)
           }
@@ -1712,8 +1711,8 @@ object Trees {
               this(this(x, body)(using quoteContext), tags)
             case Splice(expr) =>
               this(x, expr)(using spliceContext)
-            case Hole(_, _, args, content, tpt) =>
-              this(this(this(x, args), content), tpt)
+            case Hole(_, _, args, content) =>
+              this(this(x, args), content)
             case _ =>
               foldMoreCases(x, tree)
           }

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

@@ -176,6 +176,9 @@ object tpd extends Trees.Instance[Type] with TypedTreeInfo {
   def Splice(expr: Tree, tpe: Type)(using Context): Splice =
     untpd.Splice(expr).withType(tpe)
 
+  def Hole(isTerm: Boolean, idx: Int, args: List[Tree], content: Tree, tpe: Type)(using Context): Hole =
+    untpd.Hole(isTerm, idx, args, content).withType(tpe)
+
   def TypeTree(tp: Type, inferred: Boolean = false)(using Context): TypeTree =
     (if inferred then untpd.InferredTypeTree() else untpd.TypeTree()).withType(tp)
 
@@ -397,9 +400,6 @@ object tpd extends Trees.Instance[Type] with TypedTreeInfo {
   def Throw(expr: Tree)(using Context): Tree =
     ref(defn.throwMethod).appliedTo(expr)
 
-  def Hole(isTerm: Boolean, idx: Int, args: List[Tree], content: Tree, tpt: Tree)(using Context): Hole =
-    ta.assignType(untpd.Hole(isTerm, idx, args, content, tpt), tpt)
-
   // ------ Making references ------------------------------------------------------
 
   def prefixIsElidable(tp: NamedType)(using Context): Boolean = {

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

@@ -424,7 +424,7 @@ object untpd extends Trees.Instance[Untyped] with UntypedTreeInfo {
   def Export(expr: Tree, selectors: List[ImportSelector])(implicit src: SourceFile): Export = new Export(expr, selectors)
   def PackageDef(pid: RefTree, stats: List[Tree])(implicit src: SourceFile): PackageDef = new PackageDef(pid, stats)
   def Annotated(arg: Tree, annot: Tree)(implicit src: SourceFile): Annotated = new Annotated(arg, annot)
-  def Hole(isTerm: Boolean, idx: Int, args: List[Tree], content: Tree, tpt: Tree)(implicit src: SourceFile): Hole = new Hole(isTerm, idx, args, content, tpt)
+  def Hole(isTerm: Boolean, idx: Int, args: List[Tree], content: Tree)(implicit src: SourceFile): Hole = new Hole(isTerm, idx, args, content)
 
   // ------ Additional creation methods for untyped only -----------------
 

compiler/src/dotty/tools/dotc/core/tasty/TreePickler.scala

@@ -685,11 +685,11 @@ class TreePickler(pickler: TastyPickler) {
               .appliedTo(expr)
               .withSpan(tree.span)
           )
-        case Hole(_, idx, args, _, tpt) =>
+        case Hole(_, idx, args, _) =>
           writeByte(HOLE)
           withLength {
             writeNat(idx)
-            pickleType(tpt.tpe, richTypes = true)
+            pickleType(tree.tpe, richTypes = true)
             args.foreach(pickleTree)
           }
       }

compiler/src/dotty/tools/dotc/core/tasty/TreeUnpickler.scala

@@ -1457,7 +1457,7 @@ class TreeUnpickler(reader: TastyReader,
               val idx = readNat()
               val tpe = readType()
               val args = until(end)(readTree())
-              Hole(true, idx, args, EmptyTree, TypeTree(tpe)).withType(tpe)
+              Hole(true, idx, args, EmptyTree, tpe)
             case _ =>
               readPathTree()
           }
@@ -1491,7 +1491,7 @@ class TreeUnpickler(reader: TastyReader,
           val idx = readNat()
           val tpe = readType()
           val args = until(end)(readTree())
-          Hole(false, idx, args, EmptyTree, TypeTree(tpe)).withType(tpe)
+          Hole(false, idx, args, EmptyTree, tpe)
         case _ =>
           if (isTypeTreeTag(nextByte)) readTree()
           else {

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

@@ -735,12 +735,12 @@ class RefinedPrinter(_ctx: Context) extends PlainPrinter(_ctx) {
       case Splice(expr) =>
         val spliceTypeText = (keywordStr("[") ~ toTextGlobal(tree.typeOpt) ~ keywordStr("]")).provided(printDebug && tree.typeOpt.exists)
         keywordStr("$") ~ spliceTypeText ~ keywordStr("{") ~ toTextGlobal(expr) ~ keywordStr("}")
-      case Hole(isTerm, idx, args, content, tpt) =>
+      case Hole(isTerm, idx, args, content) =>
         val (prefix, postfix) = if isTerm then ("{{{", "}}}") else ("[[[", "]]]")
         val argsText = toTextGlobal(args, ", ")
         val contentText = toTextGlobal(content)
-        val tptText = toTextGlobal(tpt)
-        prefix ~~ idx.toString ~~ "|" ~~ tptText ~~ "|" ~~ argsText ~~ "|" ~~ contentText ~~ postfix
+        val tpeText = toTextGlobal(tree.typeOpt)
+        prefix ~~ idx.toString ~~ "|" ~~ tpeText ~~ "|" ~~ argsText ~~ "|" ~~ contentText ~~ postfix
       case CapturesAndResult(refs, parent) =>
         changePrec(GlobalPrec)("^{" ~ Text(refs.map(toText), ", ") ~ "}" ~ toText(parent))
       case _ =>

compiler/src/dotty/tools/dotc/quoted/PickledQuotes.scala

@@ -100,7 +100,7 @@ object PickledQuotes {
   private def spliceTerms(tree: Tree, typeHole: TypeHole, termHole: ExprHole)(using Context): Tree = {
     def evaluateHoles = new TreeMap {
       override def transform(tree: tpd.Tree)(using Context): tpd.Tree = tree match {
-        case Hole(isTerm, idx, args, _, _) =>
+        case Hole(isTerm, idx, args, _) =>
           inContext(SpliceScope.contextWithNewSpliceScope(tree.sourcePos)) {
             if isTerm then
               val quotedExpr = termHole match
@@ -165,15 +165,15 @@ object PickledQuotes {
             val tree = typeHole match
               case TypeHole.V1(evalHole) =>
                 tdef.rhs match
-                  case TypeBoundsTree(_, Hole(_, idx, args, _, _), _) =>
+                  case TypeBoundsTree(_, Hole(_, idx, args, _), _) =>
                     // To keep for backwards compatibility. In some older version holes where created in the bounds.
                     val quotedType = evalHole.nn.apply(idx, reifyTypeHoleArgs(args))
                     PickledQuotes.quotedTypeToTree(quotedType)
                   case TypeBoundsTree(_, tpt, _) =>
                     // To keep for backwards compatibility. In some older version we missed the creation of some holes.
                     tpt
               case TypeHole.V2(types) =>
-                val Hole(_, idx, _, _, _) = tdef.rhs: @unchecked
+                val Hole(_, idx, _, _) = tdef.rhs: @unchecked
                 PickledQuotes.quotedTypeToTree(types.nn.apply(idx))
             (tdef.symbol, tree.tpe)
         }.toMap

compiler/src/dotty/tools/dotc/transform/PickleQuotes.scala

@@ -14,6 +14,7 @@ import ast.TreeTypeMap
 import SymUtils._
 import NameKinds._
 import dotty.tools.dotc.ast.tpd
+import dotty.tools.dotc.ast.untpd
 import dotty.tools.dotc.config.ScalaRelease.*
 
 import scala.collection.mutable
@@ -108,12 +109,12 @@ class PickleQuotes extends MacroTransform {
       private val contents = List.newBuilder[Tree]
       override def transform(tree: tpd.Tree)(using Context): tpd.Tree =
         tree match
-          case tree @ Hole(isTerm, _, _, content, _) =>
+          case tree @ Hole(isTerm, _, _, content) =>
             assert(isTerm)
             assert(!content.isEmpty)
             contents += content
             val holeType = getTermHoleType(tree.tpe)
-            val hole = cpy.Hole(tree)(content = EmptyTree, TypeTree(holeType))
+            val hole = untpd.cpy.Hole(tree)(content = EmptyTree).withType(holeType)
             cpy.Inlined(tree)(EmptyTree, Nil, hole)
           case tree: DefTree =>
             val newAnnotations = tree.symbol.annotations.mapconserve { annot =>
@@ -197,7 +198,7 @@ class PickleQuotes extends MacroTransform {
 
   private def mkTagSymbolAndAssignType(typeArg: Tree, idx: Int)(using Context): TypeDef = {
     val holeType = getTypeHoleType(typeArg.tpe.select(tpnme.Underlying))
-    val hole = cpy.Hole(typeArg)(isTerm = false, idx, Nil, EmptyTree, TypeTree(holeType))
+    val hole = untpd.cpy.Hole(typeArg)(isTerm = false, idx, Nil, EmptyTree).withType(holeType)
     val local = newSymbol(
       owner = ctx.owner,
       name = UniqueName.fresh(hole.tpe.dealias.typeSymbol.name.toTypeName),

compiler/src/dotty/tools/dotc/transform/Splicing.scala

@@ -181,7 +181,7 @@ class Splicing extends MacroTransform:
       val ddef = DefDef(meth, List(bindings), newTree.tpe, newTree.changeOwner(ctx.owner, meth))
       val fnType = defn.FunctionType(bindings.size, isContextual = false).appliedTo(bindingsTypes :+ newTree.tpe)
       val closure = Block(ddef :: Nil, Closure(Nil, ref(meth), TypeTree(fnType)))
-      tpd.Hole(true, holeIdx, refs, closure, TypeTree(tpe))
+      tpd.Hole(true, holeIdx, refs, closure, tpe)
 
     override def transform(tree: tpd.Tree)(using Context): tpd.Tree =
       tree match

compiler/src/dotty/tools/dotc/transform/TreeChecker.scala

@@ -688,16 +688,19 @@ object TreeChecker {
       super.typedSplice(tree, pt)
 
     override def typedHole(tree: untpd.Hole, pt: Type)(using Context): Tree = {
-      val tree1 @ Hole(isTerm, _, args, content, tpt) = super.typedHole(tree, pt): @unchecked
+      val tree1 @ Hole(isTerm, idx, args, content) = super.typedHole(tree, pt): @unchecked
+
+      assert(idx >= 0, i"hole should not have negative index: $tree")
+      assert(isTerm || tree.args.isEmpty, i"type hole should not have arguments: $tree")
 
       // Check that we only add the captured type `T` instead of a more complex type like `List[T]`.
       // If we have `F[T]` with captured `F` and `T`, we should list `F` and `T` separately in the args.
       for arg <- args do
         assert(arg.isTerm || arg.tpe.isInstanceOf[TypeRef], "Expected TypeRef in Hole type args but got: " + arg.tpe)
 
       // Check result type of the hole
-      if isTerm then assert(tpt.typeOpt <:< pt)
-      else assert(tpt.typeOpt =:= pt)
+      if isTerm then assert(tree1.typeOpt <:< pt)
+      else assert(tree1.typeOpt =:= pt)
 
       // Check that the types of the args conform to the types of the contents of the hole
       val argQuotedTypes = args.map { arg =>
@@ -712,8 +715,8 @@ object TreeChecker {
         else defn.QuotedTypeClass.typeRef.appliedTo(arg.typeOpt.widenTermRefExpr)
       }
       val expectedResultType =
-        if isTerm then defn.QuotedExprClass.typeRef.appliedTo(tpt.typeOpt)
-        else defn.QuotedTypeClass.typeRef.appliedTo(tpt.typeOpt)
+        if isTerm then defn.QuotedExprClass.typeRef.appliedTo(tree1.typeOpt)
+        else defn.QuotedTypeClass.typeRef.appliedTo(tree1.typeOpt)
       val contextualResult =
         defn.FunctionOf(List(defn.QuotesClass.typeRef), expectedResultType, isContextual = true)
       val expectedContentType =