Fix info of ASF nested class

Class M1#F asSeenFrom M2 has type parameters with info of the original owner/prefix (M1). So running asSeenFrom against that info fixes the eta-expanded lambda.
dwijnand · Oct 4, 2023 · 3b99291 · 3b99291
1 parent de4ad2b
commit 3b99291
Show file tree

Hide file tree

Showing 2 changed files with 15 additions and 2 deletions.
diff --git a/compiler/src/dotty/tools/dotc/typer/Namer.scala b/compiler/src/dotty/tools/dotc/typer/Namer.scala
@@ -1175,8 +1175,12 @@ class Namer { typer: Typer =>
             if mbr.isType then
               val forwarderName = checkNoConflict(alias.toTypeName, isPrivate = false, span)
               var target = pathType.select(sym)
-              if target.typeParams.nonEmpty then
-                target = target.EtaExpand(target.typeParams)
+              val tparams = target.typeParamSymbols
+              if tparams.nonEmpty then
+                target = HKTypeLambda(tparams.map(_.paramName))(
+                  tl => tparams.map(p =>
+                    HKTypeLambda.toPInfo(tl.integrate(tparams, p.info.asSeenFrom(pathType, sym.owner)))),
+                  tl => tl.integrate(tparams, target.appliedTo(tparams.map(_.paramRef))))
               newSymbol(
                 cls, forwarderName,
                 Exported | Final,

diff --git a/tests/pos/i18569.scala b/tests/pos/i18569.scala
@@ -0,0 +1,9 @@
+trait M1:
+  trait A
+  trait F[T <: A]
+
+object M2 extends M1
+
+trait Test:
+  export M2.*
+  def y: F[A]