Allow to unpickle a skolem type in more cases

Author: jchyb

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

@@ -507,7 +507,8 @@ class TreeUnpickler(reader: TastyReader,
     private def readSymNameRef()(using Context): Type = {
       val sym = readSymRef()
       val prefix = readType()
-      val res = NamedType(prefix, sym)
+      def pre = if TypeOps.isLegalPrefix(prefix) then prefix else QualSkolemType(prefix)
+      val res = NamedType(pre, sym)
       prefix match {
         case prefix: ThisType if (prefix.cls eq sym.owner) && !sym.is(Opaque) =>
           res.withDenot(sym.denot)

tests/pos/i22585-a/inline_1.scala

@@ -0,0 +1,16 @@
+import scala.quoted.*
+
+trait Hammer[I, O] {
+  def hammer(input: I): O
+}
+
+object Hammer {
+  inline def makeHammer[S, O](): Hammer[S, O] =
+    new Hammer[S, O] {
+      lazy val (hammer: Hammer[?, Int], idx: Int) = ???
+
+      override def hammer(input: S): O = {
+        hammer.hammer(???.asInstanceOf).asInstanceOf[O]
+      }
+    }
+}

tests/pos/i22585-a/main_2.scala

@@ -0,0 +1,5 @@
+object HammerSpec {
+  case class A(x: Int)
+  case class B(x: Int)
+  Hammer.makeHammer[A, B]()
+}