SI-8285 use correct kind of map for quasiquote positions

Previously mutable.ListMap was used with assumption that it preserved
order of inserted elements (but it doesn't). Surprisingly logic that
assumed ordered elements worked mosly fine on unordered ones. I guess
two bugs can cancel each other out.

2 files changed, 7 insertions, 9 deletions

diff --git a/src/compiler/scala/tools/reflect/quasiquotes/Parsers.scala b/src/compiler/scala/tools/reflect/quasiquotes/Parsers.scala
index 3b93a8933d..b22e0b0e82 100644
--- a/src/compiler/scala/tools/reflect/quasiquotes/Parsers.scala
+++ b/src/compiler/scala/tools/reflect/quasiquotes/Parsers.scala
@@ -30,15 +30,15 @@ trait Parsers { self: Quasiquotes =>
 
     def correspondingPosition(offset: Int): Position = {
       val posMapList = posMap.toList
-      def containsOffset(start: Int, end: Int) = start <= offset && offset <= end
+      def containsOffset(start: Int, end: Int) = start <= offset && offset < end
       def fallbackPosition = posMapList match {
         case (pos1, (start1, end1)) :: _   if start1 > offset => pos1
-        case _ :+ ((pos2, (start2, end2))) if offset > end2   => pos2.withPoint(pos2.point + (end2 - start2))
+        case _ :+ ((pos2, (start2, end2))) if end2 <= offset  => pos2.withPoint(pos2.point + (end2 - start2))
       }
       posMapList.sliding(2).collect {
-        case (pos1, (start1, end1)) :: _                if containsOffset(start1, end1) => (pos1, offset - start1)
-        case (pos1, (_, end1)) :: (_, (start2, _)) :: _ if containsOffset(end1, start2) => (pos1, end1)
-        case _ :: (pos2, (start2, end2)) :: _           if containsOffset(start2, end2) => (pos2, offset - start2)
+        case (pos1, (start1, end1)) :: _                        if containsOffset(start1, end1) => (pos1, offset - start1)
+        case (pos1, (start1, end1)) :: (pos2, (start2, _)) :: _ if containsOffset(end1, start2) => (pos1, end1 - start1)
+        case _ :: (pos2, (start2, end2)) :: _                   if containsOffset(start2, end2) => (pos2, offset - start2)
       }.map { case (pos, offset) =>
         pos.withPoint(pos.point + offset)
       }.toList.headOption.getOrElse(fallbackPosition)
diff --git a/src/compiler/scala/tools/reflect/quasiquotes/Placeholders.scala b/src/compiler/scala/tools/reflect/quasiquotes/Placeholders.scala
index 5986758c2b..b287971815 100644
--- a/src/compiler/scala/tools/reflect/quasiquotes/Placeholders.scala
+++ b/src/compiler/scala/tools/reflect/quasiquotes/Placeholders.scala
@@ -17,7 +17,7 @@ trait Placeholders { self: Quasiquotes =>
 
   // Step 1: Transform Scala source with holes into vanilla Scala source
 
-  lazy val posMap = mutable.ListMap[Position, (Int, Int)]()
+  lazy val posMap = mutable.LinkedHashMap[Position, (Int, Int)]()
   lazy val code = {
     val sb = new StringBuilder()
     val sessionSuffix = randomUUID().toString.replace("-", "").substring(0, 8) + "$"
@@ -40,9 +40,7 @@ trait Placeholders { self: Quasiquotes =>
 
     val iargs = method match {
       case nme.apply   => args
-      case nme.unapply =>
-        val (dummy @ Ident(nme.SELECTOR_DUMMY)) :: Nil = args
-        internal.subpatterns(dummy).get
+      case nme.unapply => internal.subpatterns(args.head).get
       case _           => global.abort("unreachable")
     }