diff --git a/akka-stream/src/main/scala/akka/stream/impl/ActorFlowMaterializerImpl.scala b/akka-stream/src/main/scala/akka/stream/impl/ActorFlowMaterializerImpl.scala
index 9026ffee96..637ed30a84 100644
--- a/akka-stream/src/main/scala/akka/stream/impl/ActorFlowMaterializerImpl.scala
+++ b/akka-stream/src/main/scala/akka/stream/impl/ActorFlowMaterializerImpl.scala
@@ -60,7 +60,7 @@ private[akka] case class ActorFlowMaterializerImpl(
   }
 
   override def materialize[Mat](runnableFlow: Graph[ClosedShape, Mat]): Mat = {
-    runnableFlow.module.validate()
+    if (StreamLayout.Debug) runnableFlow.module.validate()
 
     val session = new MaterializerSession(runnableFlow.module) {
       private val flowName = createFlowName()
diff --git a/akka-stream/src/main/scala/akka/stream/impl/StreamLayout.scala b/akka-stream/src/main/scala/akka/stream/impl/StreamLayout.scala
index f2160a4347..0e3a704e16 100644
--- a/akka-stream/src/main/scala/akka/stream/impl/StreamLayout.scala
+++ b/akka-stream/src/main/scala/akka/stream/impl/StreamLayout.scala
@@ -19,7 +19,7 @@ import akka.event.Logging.simpleName
 private[akka] object StreamLayout {
 
   // compile-time constant
-  final val Debug = true
+  final val Debug = false
 
   // TODO: Materialization order
   // TODO: Special case linear composites
diff --git a/akka-stream/src/main/scala/akka/stream/impl/fusing/Interpreter.scala b/akka-stream/src/main/scala/akka/stream/impl/fusing/Interpreter.scala
index ed4bbc1963..330b5bc29c 100644
--- a/akka-stream/src/main/scala/akka/stream/impl/fusing/Interpreter.scala
+++ b/akka-stream/src/main/scala/akka/stream/impl/fusing/Interpreter.scala
@@ -12,11 +12,6 @@ import scala.annotation.{ switch, tailrec }
 import scala.collection.breakOut
 import scala.util.control.NonFatal
 
-// TODO:
-// fix jumpback table with keep-going-on-complete ops (we might jump between otherwise isolated execution regions)
-// implement grouped, buffer
-// add recover
-
 /**
  * INTERNAL API
  */