Fix #4380: Revert optimization that breaks owners

Implementation for optimization bf13d5b needs to be revisited.

Author: nicolasstucki

tests/pos/i4380a.scala

@@ -0,0 +1,23 @@
+import scala.quoted._
+
+object Test {
+
+  trait Producer[A] { self =>
+    def step(k: (A => Expr[Unit])): Expr[Unit]
+  }
+
+  trait Foo[A]
+  case class Bar[A, B](producer: Producer[B], nestedf: B => Expr[Unit]) extends Foo[A]
+
+  def meth[A](stream: Foo[Expr[A]]): Producer[Expr[A]] = {
+    stream match {
+      case Bar(producer, nestedf) => {
+        new Producer[Expr[A]] {
+          def step(k: Expr[A] => Expr[Unit]): Expr[Unit] = '{
+            val adv: Unit => Unit = { _ => ~producer.step((el) => nestedf(el))}
+          }
+        }
+      }
+    }
+  }
+}

tests/pos/i4380b.scala

@@ -0,0 +1,8 @@
+import scala.quoted._
+
+object Test {
+  def step(k: (String => Expr[Unit])): Expr[Unit] = '()
+  def meth(): Unit = '{
+    (i: Int) => ~step(el => '() )
+  }
+}