bugfix: Fix issue after backporting

Author: tgodzik

compiler/src/dotty/tools/dotc/transform/PostTyper.scala

@@ -369,10 +369,7 @@ class PostTyper extends MacroTransform with IdentityDenotTransformer { thisPhase
         case UnApply(fun, implicits, patterns) =>
           // Reverse transform order for the same reason as in `app1` above.
           val patterns1 = transform(patterns)
-          val tree1 = cpy.UnApply(tree)(transform(fun), transform(implicits), patterns1)
-          // The pickling of UnApply trees uses the tpe of the tree,
-          // so we need to clean retains from it here
-          tree1.withType(transformAnnotsIn(CleanupRetains()(tree1.tpe)))
+          cpy.UnApply(tree)(transform(fun), transform(implicits), patterns1)
         case tree: TypeApply =>
           if tree.symbol == defn.QuotedTypeModule_of then
             ctx.compilationUnit.needsStaging = true