Widen skolem types when adding parent refinements

Author: KacperFKorban

compiler/src/dotty/tools/dotc/core/NamerOps.scala

@@ -44,9 +44,10 @@ object NamerOps:
           try tp1.separateRefinements(cls, refinements)
           finally
             if refinements != null then
+              val rinfo1 = rinfo.widenSkolem
               refinements(rname) = refinements.get(rname) match
-                case Some(tp) => tp & rinfo
-                case None => rinfo
+                case Some(tp) => tp & rinfo1
+                case None => rinfo1
         case tp @ AnnotatedType(tp1, ann) =>
           tp.derivedAnnotatedType(tp1.separateRefinements(cls, refinements), ann)
         case tp: RecType =>

compiler/src/dotty/tools/dotc/core/tasty/TreeUnpickler.scala

@@ -1080,7 +1080,7 @@ class TreeUnpickler(reader: TastyReader,
       }
       val parentReader = fork
       val parents = readParents(withArgs = false)(using parentCtx)
-      val parentTypes = parents.map(_.tpe.dealiasKeepAnnots.separateRefinements(cls, null))
+      val parentTypes = parents.map(p => p.tpe.dealiasKeepAnnots.separateRefinements(cls, null))
       if cls.is(JavaDefined) && parentTypes.exists(_.derivesFrom(defn.JavaAnnotationClass)) then
         cls.setFlag(JavaAnnotation)
       val self =

tests/pos/i22456.scala

@@ -0,0 +1,4 @@
+import language.experimental.modularity
+
+class T(tracked val y: Int)
+class C(tracked val x: Int) extends T(x + 1)