Drop CapturingTypeTree

Author: odersky

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

@@ -1824,14 +1824,6 @@ object desugar {
         flatTree(pats1 map (makePatDef(tree, mods, _, rhs)))
       case ext: ExtMethods =>
         Block(List(ext), Literal(Constant(())).withSpan(ext.span))
-      case CapturingTypeTree(refs, parent) =>
-        // convert   `{refs} T`   to `T @retains refs`
-        //           `{refs}-> T` to `-> (T @retainsByName refs)`
-        parent match
-          case ByNameTypeTree(restpt) =>
-            cpy.ByNameTypeTree(parent)(makeRetaining(restpt, refs, tpnme.retainsByName))
-          case _ =>
-            makeRetaining(parent, refs, tpnme.retains)
       case f: FunctionWithMods if f.hasErasedParams => makeFunctionWithValDefs(f, pt)
     }
     desugared.withSpan(tree.span)
@@ -1991,8 +1983,6 @@ object desugar {
             case _ => traverseChildren(tree)
           }
         }.traverse(expr)
-      case CapturingTypeTree(refs, parent) =>
-        collect(parent)
       case _ =>
     }
     collect(tree)

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

@@ -223,9 +223,6 @@ trait TreeInfo[T <: Untyped] { self: Trees.Instance[T] =>
   /** Strip `=> T` to `T` and (under pureFunctions) `{refs}-> T` to `T` */
   def stripByNameType(tree: Tree)(using Context): Tree = unsplice(tree) match
     case ByNameTypeTree(t1) => t1
-    case untpd.CapturingTypeTree(_, parent) =>
-      val parent1 = stripByNameType(parent)
-      if parent1 eq parent then tree else parent1
     case _ => tree
 
   /** All type and value parameter symbols of this DefDef */

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

@@ -151,9 +151,6 @@ object untpd extends Trees.Instance[Untyped] with UntypedTreeInfo {
     case Floating
   }
 
-  /** {x1, ..., xN} T   (only relevant under captureChecking) */
-  case class CapturingTypeTree(refs: List[Tree], parent: Tree)(implicit @constructorOnly src: SourceFile) extends TypTree
-
   /** {x1, ..., xN} T   (only relevant under captureChecking) */
   case class CapturesAndResult(refs: List[Tree], parent: Tree)(implicit @constructorOnly src: SourceFile) extends TypTree
 
@@ -678,10 +675,6 @@ object untpd extends Trees.Instance[Untyped] with UntypedTreeInfo {
       case tree: CapturesAndResult if (refs eq tree.refs) && (parent eq tree.parent) => tree
       case _ => finalize(tree, untpd.CapturesAndResult(refs, parent))
 
-    def CapturingTypeTree(tree: Tree)(refs: List[Tree], parent: Tree)(using Context): Tree = tree match
-      case tree: CapturingTypeTree if (refs eq tree.refs) && (parent eq tree.parent) => tree
-      case _ => finalize(tree, untpd.CapturingTypeTree(refs, parent))
-
     def TypedSplice(tree: Tree)(splice: tpd.Tree)(using Context): ProxyTree = tree match {
       case tree: TypedSplice if splice `eq` tree.splice => tree
       case _ => finalize(tree, untpd.TypedSplice(splice)(using ctx))
@@ -749,8 +742,6 @@ object untpd extends Trees.Instance[Untyped] with UntypedTreeInfo {
         cpy.MacroTree(tree)(transform(expr))
       case CapturesAndResult(refs, parent) =>
         cpy.CapturesAndResult(tree)(transform(refs), transform(parent))
-      case CapturingTypeTree(refs, parent) =>
-        cpy.CapturingTypeTree(tree)(transform(refs), transform(parent))
       case _ =>
         super.transformMoreCases(tree)
     }
@@ -814,8 +805,6 @@ object untpd extends Trees.Instance[Untyped] with UntypedTreeInfo {
         this(x, expr)
       case CapturesAndResult(refs, parent) =>
         this(this(x, refs), parent)
-      case CapturingTypeTree(refs, parent) =>
-        this(this(x, refs), parent)
       case _ =>
         super.foldMoreCases(x, tree)
     }

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

@@ -742,9 +742,6 @@ class RefinedPrinter(_ctx: Context) extends PlainPrinter(_ctx) {
         prefix ~~ idx.toString ~~ "|" ~~ tptText ~~ "|" ~~ argsText ~~ "|" ~~ contentText ~~ postfix
       case CapturesAndResult(refs, parent) =>
         changePrec(GlobalPrec)("^{" ~ Text(refs.map(toText), ", ") ~ "} " ~ toText(parent))
-      case CapturingTypeTree(refs, parent) =>
-        toText(parent) ~ "^"
-        ~ changePrec(GlobalPrec)("{" ~ Text(refs.map(toText), ", ") ~ "}")
       case _ =>
         tree.fallbackToText(this)
     }