Merge pull request scala#3671 from densh/si/8466

SI-8466 fix quasiquote crash on recursively iterable unlifting

Author: retronym

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

@@ -43,13 +43,13 @@ trait Holes { self: Quasiquotes =>
     tpe <:< NothingClass.tpe || tpe <:< NullClass.tpe
   private def extractIterableTParam(tpe: Type) =
     IterableTParam.asSeenFrom(tpe, IterableClass)
-  private def stripIterable(tpe: Type, limit: Option[Rank] = None): (Rank, Type) =
-    if (limit.map { _ == NoDot }.getOrElse { false }) (NoDot, tpe)
+  private def stripIterable(tpe: Type, limit: Rank = DotDotDot): (Rank, Type) =
+    if (limit == NoDot) (NoDot, tpe)
     else if (tpe != null && !isIterableType(tpe)) (NoDot, tpe)
     else if (isBottomType(tpe)) (NoDot, tpe)
     else {
       val targ = extractIterableTParam(tpe)
-      val (rank, innerTpe) = stripIterable(targ, limit.map { _.pred })
+      val (rank, innerTpe) = stripIterable(targ, limit.pred)
       (rank.succ, innerTpe)
     }
   private def iterableTypeFromRank(n: Rank, tpe: Type): Type = {
@@ -76,7 +76,7 @@ trait Holes { self: Quasiquotes =>
 
   class ApplyHole(annotatedRank: Rank, unquotee: Tree) extends Hole {
     val (strippedTpe, tpe): (Type, Type) = {
-      val (strippedRank, strippedTpe) = stripIterable(unquotee.tpe, limit = Some(annotatedRank))
+      val (strippedRank, strippedTpe) = stripIterable(unquotee.tpe, limit = annotatedRank)
       if (isBottomType(strippedTpe)) cantSplice()
       else if (isNativeType(strippedTpe)) {
         if (strippedRank != NoDot && !(strippedTpe <:< treeType) && !isLiftableType(strippedTpe)) cantSplice()
@@ -193,7 +193,7 @@ trait Holes { self: Quasiquotes =>
         val (iterableRank, _) = stripIterable(tpe)
         if (iterableRank.value < rank.value)
           c.abort(pat.pos, s"Can't extract $tpe with $rank, consider using $iterableRank")
-        val (_, strippedTpe) = stripIterable(tpe, limit = Some(rank))
+        val (_, strippedTpe) = stripIterable(tpe, limit = rank)
         if (strippedTpe <:< treeType) treeNoUnlift
         else
           unlifters.spawn(strippedTpe, rank).map {

test/files/scalacheck/quasiquotes/LiftableProps.scala

@@ -164,4 +164,11 @@ object LiftableProps extends QuasiquoteProperties("liftable") {
     val right3: Either[Int, Int] = Right(1)
     assert(q"$right3" ≈ q"scala.util.Right(1)")
   }
+
+  property("lift xml comment") = test {
+    implicit val liftXmlComment = Liftable[xml.Comment] { comment =>
+      q"new _root_.scala.xml.Comment(${comment.commentText})"
+    }
+    assert(q"${xml.Comment("foo")}" ≈ q"<!--foo-->")
+  }
 }

test/files/scalacheck/quasiquotes/UnliftableProps.scala

@@ -155,4 +155,12 @@ object UnliftableProps extends QuasiquoteProperties("unliftable") {
     assert(t21 == (1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21))
     assert(t22 == (1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22))
   }
+
+  property("unlift xml comment") = test {
+    implicit val unliftXmlComment = Unliftable[xml.Comment] {
+      case q"new _root_.scala.xml.Comment(${value: String})" => xml.Comment(value)
+    }
+    val q"${comment: xml.Comment}" = q"<!--foo-->"
+    assert(comment.commentText == "foo")
+  }
 }