Give better names to UnliftHelper1 and UnliftHelper2

Previous ones were inscrutable but thankfully @xeno_by
helped me out to find better alternatives.;

src/compiler/scala/tools/reflect/quasiquotes/Holes.scala

@@ -166,16 +166,15 @@ trait Holes { self: Quasiquotes =>
   /** Full support for unliftable implies that it's possible to interleave
    *  deconstruction with higher cardinality and unlifting of the values.
    *  In particular extraction of List[Tree] as List[T: Unliftable] requires
-   *  helper extractors that would do the job: UnliftHelper1[T]. Similarly
-   *  List[List[Tree]] needs UnliftHelper2[T].
+   *  helper extractors that would do the job: UnliftListElementwise[T]. Similarly
+   *  List[List[Tree]] needs UnliftListOfListsElementwise[T].
    *
    *  See also "unlift list" tests in UnapplyProps.scala
    */
   object unlifters {
     private var records = List.empty[(Type, Cardinality)]
-    // Request an UnliftHelperN[T] where n == card and T == tpe.
-    // If card == 0 then helper is not needed and plain instance
-    // of unliftable is returned.
+    // Materialize unlift helper that does elementwise
+    // unlifting for corresponding cardinality and type.
     def spawn(tpe: Type, card: Cardinality): Option[Tree] = {
       val unlifter = inferUnliftable(tpe)
       if (unlifter == EmptyTree) None
@@ -190,7 +189,10 @@ trait Holes { self: Quasiquotes =>
     def preamble(): List[Tree] =
       records.zipWithIndex.map { case ((tpe, card), idx) =>
         val name = TermName(nme.QUASIQUOTE_UNLIFT_HELPER + idx)
-        val helperName = card match { case DotDot => nme.UnliftHelper1 case DotDotDot => nme.UnliftHelper2 }
+        val helperName = card match {
+          case DotDot    => nme.UnliftListElementwise
+          case DotDotDot => nme.UnliftListOfListsElementwise
+        }
         val lifter = inferUnliftable(tpe)
         assert(helperName.isTermName)
         // q"val $name: $u.build.${helperName.toTypeName} = $u.build.$helperName($lifter)"

src/reflect/scala/reflect/api/BuildUtils.scala

@@ -246,13 +246,13 @@ private[reflect] trait BuildUtils { self: Universe =>
       def unapply(tree: Tree): Option[(List[Tree], Tree)]
     }
 
-    def UnliftHelper1[T](unliftable: Unliftable[T]): UnliftHelper1[T]
-    trait UnliftHelper1[T] {
+    def UnliftListElementwise[T](unliftable: Unliftable[T]): UnliftListElementwise[T]
+    trait UnliftListElementwise[T] {
       def unapply(lst: List[Tree]): Option[List[T]]
     }
 
-    def UnliftHelper2[T](unliftable: Unliftable[T]): UnliftHelper2[T]
-    trait UnliftHelper2[T] {
+    def UnliftListOfListsElementwise[T](unliftable: Unliftable[T]): UnliftListOfListsElementwise[T]
+    trait UnliftListOfListsElementwise[T] {
       def unapply(lst: List[List[Tree]]): Option[List[List[T]]]
     }
 

src/reflect/scala/reflect/internal/BuildUtils.scala

@@ -455,14 +455,14 @@ trait BuildUtils { self: SymbolTable =>
       }
     }
 
-    def UnliftHelper1[T](unliftable: Unliftable[T]) = new UnliftHelper1[T] {
+    def UnliftListElementwise[T](unliftable: Unliftable[T]) = new UnliftListElementwise[T] {
       def unapply(lst: List[Tree]): Option[List[T]] = {
         val unlifted = lst.flatMap { unliftable.unapply(_) }
         if (unlifted.length == lst.length) Some(unlifted) else None
       }
     }
 
-    def UnliftHelper2[T](unliftable: Unliftable[T]) = new UnliftHelper2[T] {
+    def UnliftListOfListsElementwise[T](unliftable: Unliftable[T]) = new UnliftListOfListsElementwise[T] {
       def unapply(lst: List[List[Tree]]): Option[List[List[T]]] = {
         val unlifted = lst.map { l => l.flatMap { unliftable.unapply(_) } }
         if (unlifted.flatten.length == lst.flatten.length) Some(unlifted) else None

src/reflect/scala/reflect/internal/StdNames.scala

@@ -763,8 +763,8 @@ trait StdNames {
     val unapplySeq: NameType           = "unapplySeq"
     val unbox: NameType                = "unbox"
     val universe: NameType             = "universe"
-    val UnliftHelper1: NameType        = "UnliftHelper1"
-    val UnliftHelper2: NameType        = "UnliftHelper2"
+    val UnliftListElementwise: NameType = "UnliftListElementwise"
+    val UnliftListOfListsElementwise: NameType = "UnliftListOfListsElementwise"
     val update: NameType               = "update"
     val updateDynamic: NameType        = "updateDynamic"
     val value: NameType                = "value"