Fix #7159: Add missing asSeenFrom when updating denotations

Author: odersky

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

@@ -1918,13 +1918,19 @@ object Types {
             finish(symd.current)
       }
 
+      def current(sd: SingleDenotation) = finish {
+        sd.current match
+          case sdc: SymDenotation if prefix ne sdc.owner.thisType => sdc.asSeenFrom(prefix)
+          case sdc => sdc
+      }
+
       lastDenotation match {
         case lastd0: SingleDenotation =>
           val lastd = lastd0.skipRemoved
-          if (lastd.validFor.runId == ctx.runId && (checkedPeriod != Nowhere)) finish(lastd.current)
+          if (lastd.validFor.runId == ctx.runId && (checkedPeriod != Nowhere)) current(lastd)
           else lastd match {
             case lastd: SymDenotation =>
-              if (ctx.stillValid(lastd) && (checkedPeriod != Nowhere)) finish(lastd.current)
+              if (ctx.stillValid(lastd) && (checkedPeriod != Nowhere)) current(lastd)
               else finish(memberDenot(lastd.initial.name, allowPrivate = false))
             case _ =>
               fromDesignator

tests/pos/i7159.scala

@@ -0,0 +1,15 @@
+trait CompilerInterface {
+  type Tree22
+}
+
+class Reflect(val internal: CompilerInterface) {
+  opaque type Tree22 = internal.Tree22
+  def show(t: Tree22): String = ???
+}
+
+object App {
+  val refl: Reflect = ???
+  import refl._
+
+  show(??? : Tree22)
+}