Drop Pair

Drop tree node class 'Pair'. It was used only in imports, where
it can easily be replaced by Thicket.

The envisaged use for generic pairs is almost sure better modelled
by a "Pair" class in Dotty's standard library.

4 files changed, 5 insertions, 11 deletions

diff --git a/src/dotty/tools/dotc/core/tasty/TastyFormat.scala b/src/dotty/tools/dotc/core/tasty/TastyFormat.scala
index 394d8f11a..e9de68e7f 100644
--- a/src/dotty/tools/dotc/core/tasty/TastyFormat.scala
+++ b/src/dotty/tools/dotc/core/tasty/TastyFormat.scala
@@ -74,7 +74,6 @@ Standard-Section: "ASTs" TopLevelStat*
                   SELECT                possiblySigned_NameRef qual_Term
                   NEW                   cls_Type
                   SUPER          Length this_Term mixinTrait_Type?
-                  PAIR           Length left_Term right_Term
                   TYPED          Length expr_Term ascription_Type
                   NAMEDARG       Length paramName_NameRef arg_Term
                   ASSIGN         Length lhs_Term rhs_Term
@@ -300,7 +299,8 @@ object TastyFormat {
   final val RENAMED = 138
   final val APPLY = 139
   final val TYPEAPPLY = 140
-  final val PAIR = 142
+
+
   final val TYPED = 143
   final val NAMEDARG = 144
   final val ASSIGN = 145
@@ -452,7 +452,6 @@ object TastyFormat {
     case APPLY => "APPLY"
     case TYPEAPPLY => "TYPEAPPLY"
     case NEW => "NEW"
-    case PAIR => "PAIR"
     case TYPED => "TYPED"
     case NAMEDARG => "NAMEDARG"
     case ASSIGN => "ASSIGN"
diff --git a/src/dotty/tools/dotc/core/tasty/TreePickler.scala b/src/dotty/tools/dotc/core/tasty/TreePickler.scala
index be3999533..e5cacfc00 100644
--- a/src/dotty/tools/dotc/core/tasty/TreePickler.scala
+++ b/src/dotty/tools/dotc/core/tasty/TreePickler.scala
@@ -392,9 +392,6 @@ class TreePickler(pickler: TastyPickler) {
       case New(tpt) =>
         writeByte(NEW)
         pickleTpt(tpt)
-      case Pair(left, right) =>
-        writeByte(PAIR)
-        withLength { pickleTree(left); pickleTree(right) }
       case Typed(expr, tpt) =>
         writeByte(TYPED)
         withLength { pickleTree(expr); pickleTpt(tpt) }
@@ -496,7 +493,7 @@ class TreePickler(pickler: TastyPickler) {
         withLength {
           pickleTree(expr)
           selectors foreach {
-            case Pair(Ident(from), Ident(to)) =>
+            case Thicket(Ident(from) :: Ident(to) :: Nil) =>
               writeByte(RENAMED)
               withLength { pickleName(from); pickleName(to) }
             case Ident(name) =>
diff --git a/src/dotty/tools/dotc/core/tasty/TreeUnpickler.scala b/src/dotty/tools/dotc/core/tasty/TreeUnpickler.scala
index 31247c005..f7363e72b 100644
--- a/src/dotty/tools/dotc/core/tasty/TreeUnpickler.scala
+++ b/src/dotty/tools/dotc/core/tasty/TreeUnpickler.scala
@@ -831,7 +831,7 @@ class TreeUnpickler(reader: TastyReader, tastyName: TastyName.Table) {
         case RENAMED =>
           readByte()
           readEnd()
-          untpd.Pair(untpd.Ident(readName()), untpd.Ident(readName())) :: readSelectors()
+          untpd.Thicket(untpd.Ident(readName()), untpd.Ident(readName())) :: readSelectors()
         case IMPORTED =>
           readByte()
           untpd.Ident(readName()) :: readSelectors()
@@ -915,8 +915,6 @@ class TreeUnpickler(reader: TastyReader, tastyName: TastyName.Table) {
               tpd.Apply(fn, until(end)(readArg()))
             case TYPEAPPLY =>
               tpd.TypeApply(readTerm(), until(end)(readTpt()))
-            case PAIR =>
-              Pair(readTerm(), readTerm())
             case TYPED =>
               val expr = readTerm()
               val tpt = readTpt()
diff --git a/src/dotty/tools/dotc/core/unpickleScala2/Scala2Unpickler.scala b/src/dotty/tools/dotc/core/unpickleScala2/Scala2Unpickler.scala
index 371d20e60..a667438be 100644
--- a/src/dotty/tools/dotc/core/unpickleScala2/Scala2Unpickler.scala
+++ b/src/dotty/tools/dotc/core/unpickleScala2/Scala2Unpickler.scala
@@ -1044,7 +1044,7 @@ class Scala2Unpickler(bytes: Array[Byte], classRoot: ClassDenotation, moduleClas
           val toName = readNameRef()
           val from = untpd.Ident(fromName)
           val to = untpd.Ident(toName)
-          if (toName.isEmpty) from else untpd.Pair(from, untpd.Ident(toName))
+          if (toName.isEmpty) from else untpd.Thicket(from, untpd.Ident(toName))
         })
 
         Import(expr, selectors)