Change encoding of capturing ByNameTypeTrees

Author: odersky

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

@@ -473,13 +473,15 @@ trait UntypedTreeInfo extends TreeInfo[Untyped] { self: Trees.Instance[Untyped]
    */
   object ImpureByNameTypeTree:
 
-    def apply(tp: ByNameTypeTree)(using Context): untpd.CapturingTypeTree =
-      untpd.CapturingTypeTree(
-        untpd.captureRoot.withSpan(tp.span.startPos) :: Nil, tp)
-
-    def unapply(tp: Tree)(using Context): Option[ByNameTypeTree] = tp match
-      case untpd.CapturingTypeTree(id @ Select(_, nme.CAPTURE_ROOT) :: Nil, bntp: ByNameTypeTree)
-      if id.span == bntp.span.startPos => Some(bntp)
+    def apply(tp: Tree)(using Context): untpd.ByNameTypeTree =
+      untpd.ByNameTypeTree(
+        untpd.CapturesAndResult(
+          untpd.captureRoot.withSpan(tp.span.startPos) :: Nil, tp))
+
+    def unapply(tp: Tree)(using Context): Option[Tree] = tp match
+      case untpd.ByNameTypeTree(
+        untpd.CapturesAndResult(id @ Select(_, nme.CAPTURE_ROOT) :: Nil, result))
+      if id.span == result.span.startPos => Some(result)
       case _ => None
   end ImpureByNameTypeTree
 }

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

@@ -1935,9 +1935,10 @@ object Parsers {
     def paramTypeOf(core: () => Tree): Tree =
       if in.token == ARROW || isPureArrow(nme.PUREARROW) then
         val isImpure = in.token == ARROW
-        val tp = atSpan(in.skipToken()):
-          ByNameTypeTree(if isImpure then core() else capturesAndResult(core))
-        if isImpure && Feature.pureFunsEnabled then ImpureByNameTypeTree(tp) else tp
+        atSpan(in.skipToken()):
+          val tp = if isImpure then core() else capturesAndResult(core)
+          if isImpure && Feature.pureFunsEnabled then ImpureByNameTypeTree(tp)
+          else ByNameTypeTree(tp)
       else
         core()
 

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

@@ -570,9 +570,10 @@ class RefinedPrinter(_ctx: Context) extends PlainPrinter(_ctx) {
           toText(sel) ~ keywordStr(" match ") ~ blockText(cases) ~
           (" <: " ~ toText(bound) provided !bound.isEmpty)
         }
+      case ImpureByNameTypeTree(tpt) =>
+        "=> " ~ toTextLocal(tpt)
       case ByNameTypeTree(tpt) =>
-        (if Feature.pureFunsEnabled then "-> " else "=> ")
-        ~ toTextLocal(tpt)
+        (if Feature.pureFunsEnabled then "-> " else "=> ") ~ toTextLocal(tpt)
       case TypeBoundsTree(lo, hi, alias) =>
         if (lo eq hi) && alias.isEmpty then optText(lo)(" = " ~ _)
         else optText(lo)(" >: " ~ _) ~ optText(hi)(" <: " ~ _) ~ optText(alias)(" = " ~ _)
@@ -742,12 +743,8 @@ class RefinedPrinter(_ctx: Context) extends PlainPrinter(_ctx) {
       case CapturesAndResult(refs, parent) =>
         changePrec(GlobalPrec)("^{" ~ Text(refs.map(toText), ", ") ~ "} " ~ toText(parent))
       case CapturingTypeTree(refs, parent) =>
-        parent match
-          case ImpureByNameTypeTree(bntpt) =>
-            "=> " ~ toTextLocal(bntpt)
-          case _ =>
-            toText(parent) ~ "^"
-            ~ changePrec(GlobalPrec)("{" ~ Text(refs.map(toText), ", ") ~ "}")
+        toText(parent) ~ "^"
+        ~ changePrec(GlobalPrec)("{" ~ Text(refs.map(toText), ", ") ~ "}")
       case _ =>
         tree.fallbackToText(this)
     }