diff --git a/akka-stream-tests/src/test/java/akka/stream/javadsl/BidiFlowTest.java b/akka-stream-tests/src/test/java/akka/stream/javadsl/BidiFlowTest.java
index 3b15ce7b36..d20f398a34 100644
--- a/akka-stream-tests/src/test/java/akka/stream/javadsl/BidiFlowTest.java
+++ b/akka-stream-tests/src/test/java/akka/stream/javadsl/BidiFlowTest.java
@@ -272,4 +272,10 @@ public class BidiFlowTest extends StreamTest {
     Arrays.sort(rr);
     assertArrayEquals(new Long[] { 3L, 12L }, rr);
   }
+  
+  public void mustSuitablyOverrideAttributeHandlingMethods() {
+    @SuppressWarnings("unused")
+    final BidiFlow<Integer, Long, ByteString, String, BoxedUnit> b =
+        bidi.withAttributes(Attributes.name("")).addAttributes(Attributes.asyncBoundary()).named("");
+  }
 }
diff --git a/akka-stream-tests/src/test/java/akka/stream/javadsl/FlowTest.java b/akka-stream-tests/src/test/java/akka/stream/javadsl/FlowTest.java
index 61c7eef48a..bc1d87864e 100644
--- a/akka-stream-tests/src/test/java/akka/stream/javadsl/FlowTest.java
+++ b/akka-stream-tests/src/test/java/akka/stream/javadsl/FlowTest.java
@@ -785,4 +785,9 @@ public class FlowTest extends StreamTest {
     assertEquals((Object) 0, result);
   }
 
+  public void mustSuitablyOverrideAttributeHandlingMethods() {
+    @SuppressWarnings("unused")
+    final Flow<Integer, Integer, BoxedUnit> f =
+        Flow.of(Integer.class).withAttributes(Attributes.name("")).addAttributes(Attributes.asyncBoundary()).named("");
+  }
 }
diff --git a/akka-stream-tests/src/test/java/akka/stream/javadsl/SinkTest.java b/akka-stream-tests/src/test/java/akka/stream/javadsl/SinkTest.java
index b0bbb22a13..80b688a549 100644
--- a/akka-stream-tests/src/test/java/akka/stream/javadsl/SinkTest.java
+++ b/akka-stream-tests/src/test/java/akka/stream/javadsl/SinkTest.java
@@ -13,16 +13,13 @@ import java.util.concurrent.TimeUnit;
 import akka.actor.ActorRef;
 import akka.japi.function.Function;
 import akka.japi.function.Procedure;
-import akka.stream.Graph;
-import akka.stream.UniformFanInShape;
-import akka.stream.UniformFanOutShape;
+import akka.stream.*;
 import org.junit.ClassRule;
 import org.junit.Test;
 import org.reactivestreams.Publisher;
 import scala.concurrent.Await;
 import scala.concurrent.Future;
 import scala.concurrent.duration.Duration;
-import akka.stream.StreamTest;
 import akka.japi.function.Function2;
 import akka.stream.testkit.AkkaSpec;
 import akka.testkit.JavaTestKit;
@@ -101,4 +98,9 @@ public class SinkTest extends StreamTest {
     probe2.expectMsgEquals("done2");
   }
 
+  public void mustSuitablyOverrideAttributeHandlingMethods() {
+    @SuppressWarnings("unused")
+    final Sink<Integer, Future<Integer>> s =
+        Sink.<Integer> head().withAttributes(Attributes.name("")).addAttributes(Attributes.asyncBoundary()).named("");
+  }
 }
diff --git a/akka-stream-tests/src/test/java/akka/stream/javadsl/SourceTest.java b/akka-stream-tests/src/test/java/akka/stream/javadsl/SourceTest.java
index 82543d17d9..cca8422953 100644
--- a/akka-stream-tests/src/test/java/akka/stream/javadsl/SourceTest.java
+++ b/akka-stream-tests/src/test/java/akka/stream/javadsl/SourceTest.java
@@ -11,10 +11,7 @@ import akka.dispatch.OnSuccess;
 import akka.japi.JavaPartialFunction;
 import akka.japi.Pair;
 import akka.japi.function.*;
-import akka.stream.Graph;
-import akka.stream.OverflowStrategy;
-import akka.stream.StreamTest;
-import akka.stream.UniformFanInShape;
+import akka.stream.*;
 import akka.stream.impl.ConstantFun;
 import akka.stream.stage.*;
 import akka.stream.testkit.AkkaSpec;
@@ -776,4 +773,9 @@ public class SourceTest extends StreamTest {
     assertEquals((Object) 0, result);
   }
 
+  public void mustSuitablyOverrideAttributeHandlingMethods() {
+    @SuppressWarnings("unused")
+    final Source<Integer, BoxedUnit> f =
+        Source.single(42).withAttributes(Attributes.name("")).addAttributes(Attributes.asyncBoundary()).named("");
+  }
 }
diff --git a/akka-stream-tests/src/test/scala/akka/stream/scaladsl/BidiFlowSpec.scala b/akka-stream-tests/src/test/scala/akka/stream/scaladsl/BidiFlowSpec.scala
index b05d906a0f..7e87519ca6 100644
--- a/akka-stream-tests/src/test/scala/akka/stream/scaladsl/BidiFlowSpec.scala
+++ b/akka-stream-tests/src/test/scala/akka/stream/scaladsl/BidiFlowSpec.scala
@@ -111,6 +111,11 @@ class BidiFlowSpec extends AkkaSpec with ConversionCheckedTripleEquals {
       Await.result(r, 1.second).toSet should ===(Set(3L, 12L))
     }
 
+    "suitably override attribute handling methods" in {
+      import Attributes._
+      val b: BidiFlow[Int, Long, ByteString, String, Unit] = bidi.withAttributes(name("")).addAttributes(asyncBoundary).named("")
+    }
+
   }
 
 }
diff --git a/akka-stream-tests/src/test/scala/akka/stream/scaladsl/FlowSpec.scala b/akka-stream-tests/src/test/scala/akka/stream/scaladsl/FlowSpec.scala
index 8caa8e8201..a93f305c04 100644
--- a/akka-stream-tests/src/test/scala/akka/stream/scaladsl/FlowSpec.scala
+++ b/akka-stream-tests/src/test/scala/akka/stream/scaladsl/FlowSpec.scala
@@ -586,6 +586,11 @@ class FlowSpec extends AkkaSpec(ConfigFactory.parseString("akka.actor.debug.rece
         }
       }
     }
+
+    "suitably override attribute handling methods" in {
+      import Attributes._
+      val f: Flow[Int, Int, Unit] = Flow[Int].withAttributes(asyncBoundary).addAttributes(none).named("")
+    }
   }
 
   object TestException extends RuntimeException with NoStackTrace
diff --git a/akka-stream-tests/src/test/scala/akka/stream/scaladsl/SinkSpec.scala b/akka-stream-tests/src/test/scala/akka/stream/scaladsl/SinkSpec.scala
index 708c6ee431..aaccae0480 100644
--- a/akka-stream-tests/src/test/scala/akka/stream/scaladsl/SinkSpec.scala
+++ b/akka-stream-tests/src/test/scala/akka/stream/scaladsl/SinkSpec.scala
@@ -3,9 +3,10 @@
  */
 package akka.stream.scaladsl
 
-import akka.stream.{ SinkShape, ActorMaterializer }
+import akka.stream._
 import akka.stream.testkit.TestPublisher.ManualProbe
 import akka.stream.testkit._
+import scala.concurrent.Future
 
 class SinkSpec extends AkkaSpec {
 
@@ -119,6 +120,10 @@ class SinkSpec extends AkkaSpec {
       }
     }
 
+    "suitably override attribute handling methods" in {
+      import Attributes._
+      val s: Sink[Int, Future[Int]] = Sink.head[Int].withAttributes(asyncBoundary).addAttributes(none).named("")
+    }
   }
 
 }
diff --git a/akka-stream-tests/src/test/scala/akka/stream/scaladsl/SourceSpec.scala b/akka-stream-tests/src/test/scala/akka/stream/scaladsl/SourceSpec.scala
index ce3576b635..6bcd64aa69 100644
--- a/akka-stream-tests/src/test/scala/akka/stream/scaladsl/SourceSpec.scala
+++ b/akka-stream-tests/src/test/scala/akka/stream/scaladsl/SourceSpec.scala
@@ -10,7 +10,7 @@ import scala.concurrent.{ Future, Await }
 import scala.concurrent.duration._
 import scala.util.Failure
 import scala.util.control.NoStackTrace
-import akka.stream.{ SourceShape, ActorMaterializer }
+import akka.stream._
 import akka.stream.testkit._
 
 class SourceSpec extends AkkaSpec with DefaultTimeout with ScalaFutures {
@@ -268,4 +268,11 @@ class SourceSpec extends AkkaSpec with DefaultTimeout with ScalaFutures {
     }
   }
 
+  "A Source" must {
+    "suitably override attribute handling methods" in {
+      import Attributes._
+      val s: Source[Int, Unit] = Source.single(42).withAttributes(asyncBoundary).addAttributes(none).named("")
+    }
+  }
+
 }
diff --git a/akka-stream/src/main/scala/akka/stream/impl/SubFlowImpl.scala b/akka-stream/src/main/scala/akka/stream/impl/SubFlowImpl.scala
index cb8951606f..9dbbbdd849 100644
--- a/akka-stream/src/main/scala/akka/stream/impl/SubFlowImpl.scala
+++ b/akka-stream/src/main/scala/akka/stream/impl/SubFlowImpl.scala
@@ -28,6 +28,12 @@ class SubFlowImpl[In, Out, Mat, F[+_], C](val subFlow: Flow[In, Out, Unit],
   override def withAttributes(attr: Attributes): SubFlow[Out, Mat, F, C] =
     new SubFlowImpl[In, Out, Mat, F, C](subFlow.withAttributes(attr), mergeBackFunction, finishFunction)
 
+  override def addAttributes(attr: Attributes): SubFlow[Out, Mat, F, C] =
+    new SubFlowImpl[In, Out, Mat, F, C](subFlow.addAttributes(attr), mergeBackFunction, finishFunction)
+
+  override def named(name: String): SubFlow[Out, Mat, F, C] =
+    new SubFlowImpl[In, Out, Mat, F, C](subFlow.named(name), mergeBackFunction, finishFunction)
+
   override def mergeSubstreamsWithParallelism(breadth: Int): F[Out] = mergeBackFunction(subFlow, breadth)
 
   def to[M](sink: Graph[SinkShape[Out], M]): C = finishFunction(subFlow.to(sink))
diff --git a/akka-stream/src/main/scala/akka/stream/javadsl/BidiFlow.scala b/akka-stream/src/main/scala/akka/stream/javadsl/BidiFlow.scala
index dd1bda470c..490932f5f0 100644
--- a/akka-stream/src/main/scala/akka/stream/javadsl/BidiFlow.scala
+++ b/akka-stream/src/main/scala/akka/stream/javadsl/BidiFlow.scala
@@ -192,6 +192,28 @@ final class BidiFlow[-I1, +O1, -I2, +O2, +Mat](delegate: scaladsl.BidiFlow[I1, O
   def mapMaterializedValue[Mat2](f: function.Function[Mat, Mat2]): BidiFlow[I1, O1, I2, O2, Mat2] =
     new BidiFlow(delegate.mapMaterializedValue(f.apply _))
 
+  /**
+   * Change the attributes of this [[Source]] to the given ones and seal the list
+   * of attributes. This means that further calls will not be able to remove these
+   * attributes, but instead add new ones. Note that this
+   * operation has no effect on an empty Flow (because the attributes apply
+   * only to the contained processing stages).
+   */
   override def withAttributes(attr: Attributes): BidiFlow[I1, O1, I2, O2, Mat] =
     new BidiFlow(delegate.withAttributes(attr))
+
+  /**
+   * Add the given attributes to this Source. Further calls to `withAttributes`
+   * will not remove these attributes. Note that this
+   * operation has no effect on an empty Flow (because the attributes apply
+   * only to the contained processing stages).
+   */
+  override def addAttributes(attr: Attributes): BidiFlow[I1, O1, I2, O2, Mat] =
+    new BidiFlow(delegate.addAttributes(attr))
+
+  /**
+   * Add a ``name`` attribute to this Flow.
+   */
+  override def named(name: String): BidiFlow[I1, O1, I2, O2, Mat] =
+    new BidiFlow(delegate.named(name))
 }
diff --git a/akka-stream/src/main/scala/akka/stream/javadsl/Flow.scala b/akka-stream/src/main/scala/akka/stream/javadsl/Flow.scala
index 54f9477742..b1fbe4b14f 100644
--- a/akka-stream/src/main/scala/akka/stream/javadsl/Flow.scala
+++ b/akka-stream/src/main/scala/akka/stream/javadsl/Flow.scala
@@ -1431,9 +1431,28 @@ final class Flow[-In, +Out, +Mat](delegate: scaladsl.Flow[In, Out, Mat]) extends
   def initialDelay(delay: FiniteDuration): javadsl.Flow[In, Out, Mat] =
     new Flow(delegate.initialDelay(delay))
 
+  /**
+   * Change the attributes of this [[Source]] to the given ones and seal the list
+   * of attributes. This means that further calls will not be able to remove these
+   * attributes, but instead add new ones. Note that this
+   * operation has no effect on an empty Flow (because the attributes apply
+   * only to the contained processing stages).
+   */
   override def withAttributes(attr: Attributes): javadsl.Flow[In, Out, Mat] =
     new Flow(delegate.withAttributes(attr))
 
+  /**
+   * Add the given attributes to this Source. Further calls to `withAttributes`
+   * will not remove these attributes. Note that this
+   * operation has no effect on an empty Flow (because the attributes apply
+   * only to the contained processing stages).
+   */
+  override def addAttributes(attr: Attributes): javadsl.Flow[In, Out, Mat] =
+    new Flow(delegate.addAttributes(attr))
+
+  /**
+   * Add a ``name`` attribute to this Flow.
+   */
   override def named(name: String): javadsl.Flow[In, Out, Mat] =
     new Flow(delegate.named(name))
 
diff --git a/akka-stream/src/main/scala/akka/stream/javadsl/Sink.scala b/akka-stream/src/main/scala/akka/stream/javadsl/Sink.scala
index ef13ce7f40..3c0ed80ab0 100644
--- a/akka-stream/src/main/scala/akka/stream/javadsl/Sink.scala
+++ b/akka-stream/src/main/scala/akka/stream/javadsl/Sink.scala
@@ -259,9 +259,28 @@ final class Sink[-In, +Mat](delegate: scaladsl.Sink[In, Mat]) extends Graph[Sink
   def mapMaterializedValue[Mat2](f: function.Function[Mat, Mat2]): Sink[In, Mat2] =
     new Sink(delegate.mapMaterializedValue(f.apply _))
 
+  /**
+   * Change the attributes of this [[Source]] to the given ones and seal the list
+   * of attributes. This means that further calls will not be able to remove these
+   * attributes, but instead add new ones. Note that this
+   * operation has no effect on an empty Flow (because the attributes apply
+   * only to the contained processing stages).
+   */
   override def withAttributes(attr: Attributes): javadsl.Sink[In, Mat] =
     new Sink(delegate.withAttributes(attr))
 
+  /**
+   * Add the given attributes to this Source. Further calls to `withAttributes`
+   * will not remove these attributes. Note that this
+   * operation has no effect on an empty Flow (because the attributes apply
+   * only to the contained processing stages).
+   */
+  override def addAttributes(attr: Attributes): javadsl.Sink[In, Mat] =
+    new Sink(delegate.addAttributes(attr))
+
+  /**
+   * Add a ``name`` attribute to this Flow.
+   */
   override def named(name: String): javadsl.Sink[In, Mat] =
     new Sink(delegate.named(name))
 }
diff --git a/akka-stream/src/main/scala/akka/stream/javadsl/Source.scala b/akka-stream/src/main/scala/akka/stream/javadsl/Source.scala
index 7baaddb18d..33d214ed58 100644
--- a/akka-stream/src/main/scala/akka/stream/javadsl/Source.scala
+++ b/akka-stream/src/main/scala/akka/stream/javadsl/Source.scala
@@ -1599,9 +1599,28 @@ final class Source[+Out, +Mat](delegate: scaladsl.Source[Out, Mat]) extends Grap
   def initialDelay(delay: FiniteDuration): javadsl.Source[Out, Mat] =
     new Source(delegate.initialDelay(delay))
 
+  /**
+   * Change the attributes of this [[Source]] to the given ones and seal the list
+   * of attributes. This means that further calls will not be able to remove these
+   * attributes, but instead add new ones. Note that this
+   * operation has no effect on an empty Flow (because the attributes apply
+   * only to the contained processing stages).
+   */
   override def withAttributes(attr: Attributes): javadsl.Source[Out, Mat] =
     new Source(delegate.withAttributes(attr))
 
+  /**
+   * Add the given attributes to this Source. Further calls to `withAttributes`
+   * will not remove these attributes. Note that this
+   * operation has no effect on an empty Flow (because the attributes apply
+   * only to the contained processing stages).
+   */
+  override def addAttributes(attr: Attributes): javadsl.Source[Out, Mat] =
+    new Source(delegate.addAttributes(attr))
+
+  /**
+   * Add a ``name`` attribute to this Flow.
+   */
   override def named(name: String): javadsl.Source[Out, Mat] =
     new Source(delegate.named(name))
 
diff --git a/akka-stream/src/main/scala/akka/stream/javadsl/SubFlow.scala b/akka-stream/src/main/scala/akka/stream/javadsl/SubFlow.scala
index 654c29e27a..9a2e2f35f1 100644
--- a/akka-stream/src/main/scala/akka/stream/javadsl/SubFlow.scala
+++ b/akka-stream/src/main/scala/akka/stream/javadsl/SubFlow.scala
@@ -1040,9 +1040,28 @@ class SubFlow[-In, +Out, +Mat](delegate: scaladsl.SubFlow[Out, Mat, scaladsl.Flo
   def initialDelay(delay: FiniteDuration): SubFlow[In, Out, Mat] =
     new SubFlow(delegate.initialDelay(delay))
 
+  /**
+   * Change the attributes of this [[Source]] to the given ones and seal the list
+   * of attributes. This means that further calls will not be able to remove these
+   * attributes, but instead add new ones. Note that this
+   * operation has no effect on an empty Flow (because the attributes apply
+   * only to the contained processing stages).
+   */
   def withAttributes(attr: Attributes): SubFlow[In, Out, Mat] =
     new SubFlow(delegate.withAttributes(attr))
 
+  /**
+   * Add the given attributes to this Source. Further calls to `withAttributes`
+   * will not remove these attributes. Note that this
+   * operation has no effect on an empty Flow (because the attributes apply
+   * only to the contained processing stages).
+   */
+  def addAttributes(attr: Attributes): SubFlow[In, Out, Mat] =
+    new SubFlow(delegate.addAttributes(attr))
+
+  /**
+   * Add a ``name`` attribute to this Flow.
+   */
   def named(name: String): SubFlow[In, Out, Mat] =
     new SubFlow(delegate.named(name))
 
diff --git a/akka-stream/src/main/scala/akka/stream/javadsl/SubSource.scala b/akka-stream/src/main/scala/akka/stream/javadsl/SubSource.scala
index 4e23a20864..cc5121c282 100644
--- a/akka-stream/src/main/scala/akka/stream/javadsl/SubSource.scala
+++ b/akka-stream/src/main/scala/akka/stream/javadsl/SubSource.scala
@@ -1039,9 +1039,28 @@ class SubSource[+Out, +Mat](delegate: scaladsl.SubFlow[Out, Mat, scaladsl.Source
   def initialDelay(delay: FiniteDuration): SubSource[Out, Mat] =
     new SubSource(delegate.initialDelay(delay))
 
+  /**
+   * Change the attributes of this [[Source]] to the given ones and seal the list
+   * of attributes. This means that further calls will not be able to remove these
+   * attributes, but instead add new ones. Note that this
+   * operation has no effect on an empty Flow (because the attributes apply
+   * only to the contained processing stages).
+   */
   def withAttributes(attr: Attributes): SubSource[Out, Mat] =
     new SubSource(delegate.withAttributes(attr))
 
+  /**
+   * Add the given attributes to this Source. Further calls to `withAttributes`
+   * will not remove these attributes. Note that this
+   * operation has no effect on an empty Flow (because the attributes apply
+   * only to the contained processing stages).
+   */
+  def addAttributes(attr: Attributes): SubSource[Out, Mat] =
+    new SubSource(delegate.addAttributes(attr))
+
+  /**
+   * Add a ``name`` attribute to this Flow.
+   */
   def named(name: String): SubSource[Out, Mat] =
     new SubSource(delegate.named(name))
 
diff --git a/akka-stream/src/main/scala/akka/stream/scaladsl/BidiFlow.scala b/akka-stream/src/main/scala/akka/stream/scaladsl/BidiFlow.scala
index fd12c42a8f..9b652997e8 100644
--- a/akka-stream/src/main/scala/akka/stream/scaladsl/BidiFlow.scala
+++ b/akka-stream/src/main/scala/akka/stream/scaladsl/BidiFlow.scala
@@ -128,9 +128,28 @@ final class BidiFlow[-I1, +O1, -I2, +O2, +Mat](private[stream] override val modu
   def mapMaterializedValue[Mat2](f: Mat ⇒ Mat2): BidiFlow[I1, O1, I2, O2, Mat2] =
     new BidiFlow(module.transformMaterializedValue(f.asInstanceOf[Any ⇒ Any]))
 
+  /**
+   * Change the attributes of this [[Source]] to the given ones and seal the list
+   * of attributes. This means that further calls will not be able to remove these
+   * attributes, but instead add new ones. Note that this
+   * operation has no effect on an empty Flow (because the attributes apply
+   * only to the contained processing stages).
+   */
   override def withAttributes(attr: Attributes): BidiFlow[I1, O1, I2, O2, Mat] =
     new BidiFlow(module.withAttributes(attr).nest())
 
+  /**
+   * Add the given attributes to this Source. Further calls to `withAttributes`
+   * will not remove these attributes. Note that this
+   * operation has no effect on an empty Flow (because the attributes apply
+   * only to the contained processing stages).
+   */
+  override def addAttributes(attr: Attributes): BidiFlow[I1, O1, I2, O2, Mat] =
+    withAttributes(module.attributes and attr)
+
+  /**
+   * Add a ``name`` attribute to this Flow.
+   */
   override def named(name: String): BidiFlow[I1, O1, I2, O2, Mat] =
     withAttributes(Attributes.name(name))
 }
diff --git a/akka-stream/src/main/scala/akka/stream/scaladsl/Flow.scala b/akka-stream/src/main/scala/akka/stream/scaladsl/Flow.scala
index ed1c966b65..7be555689b 100644
--- a/akka-stream/src/main/scala/akka/stream/scaladsl/Flow.scala
+++ b/akka-stream/src/main/scala/akka/stream/scaladsl/Flow.scala
@@ -202,14 +202,27 @@ final class Flow[-In, +Out, +Mat](private[stream] override val module: Module)
   }
 
   /**
-   * Change the attributes of this [[Flow]] to the given ones. Note that this
+   * Change the attributes of this [[Flow]] to the given ones and seal the list
+   * of attributes. This means that further calls will not be able to remove these
+   * attributes, but instead add new ones. Note that this
    * operation has no effect on an empty Flow (because the attributes apply
    * only to the contained processing stages).
    */
   override def withAttributes(attr: Attributes): Repr[Out] =
-    if (this.module eq EmptyModule) this
+    if (isIdentity) this
     else new Flow(module.withAttributes(attr).nest())
 
+  /**
+   * Add the given attributes to this Flow. Further calls to `withAttributes`
+   * will not remove these attributes. Note that this
+   * operation has no effect on an empty Flow (because the attributes apply
+   * only to the contained processing stages).
+   */
+  override def addAttributes(attr: Attributes): Repr[Out] = withAttributes(module.attributes and attr)
+
+  /**
+   * Add a ``name`` attribute to this Flow.
+   */
   override def named(name: String): Repr[Out] = withAttributes(Attributes.name(name))
 
   /**
@@ -1585,7 +1598,9 @@ trait FlowOps[+Out, +Mat] {
 
   def withAttributes(attr: Attributes): Repr[Out]
 
-  def named(name: String): Repr[Out] = withAttributes(Attributes.name(name))
+  def addAttributes(attr: Attributes): Repr[Out]
+
+  def named(name: String): Repr[Out]
 
   /** INTERNAL API */
   private[scaladsl] def andThen[T](op: SymbolicStage[Out, T]): Repr[T] =
diff --git a/akka-stream/src/main/scala/akka/stream/scaladsl/Graph.scala b/akka-stream/src/main/scala/akka/stream/scaladsl/Graph.scala
index 0caa93b1b8..1a2d07037c 100644
--- a/akka-stream/src/main/scala/akka/stream/scaladsl/Graph.scala
+++ b/akka-stream/src/main/scala/akka/stream/scaladsl/Graph.scala
@@ -904,6 +904,12 @@ object GraphDSL extends GraphApply {
       override def withAttributes(attr: Attributes): Repr[Out] =
         throw new UnsupportedOperationException("Cannot set attributes on chained ops from a junction output port")
 
+      override def addAttributes(attr: Attributes): Repr[Out] =
+        throw new UnsupportedOperationException("Cannot set attributes on chained ops from a junction output port")
+
+      override def named(name: String): Repr[Out] =
+        throw new UnsupportedOperationException("Cannot set attributes on chained ops from a junction output port")
+
       override def importAndGetPort(b: Builder[_]): Outlet[Out @uncheckedVariance] = outlet
 
       override def via[T, Mat2](flow: Graph[FlowShape[Out, T], Mat2]): Repr[T] =
diff --git a/akka-stream/src/main/scala/akka/stream/scaladsl/Sink.scala b/akka-stream/src/main/scala/akka/stream/scaladsl/Sink.scala
index bc02859882..686a7d3451 100644
--- a/akka-stream/src/main/scala/akka/stream/scaladsl/Sink.scala
+++ b/akka-stream/src/main/scala/akka/stream/scaladsl/Sink.scala
@@ -40,9 +40,28 @@ final class Sink[-In, +Mat](private[stream] override val module: Module)
   def mapMaterializedValue[Mat2](f: Mat ⇒ Mat2): Sink[In, Mat2] =
     new Sink(module.transformMaterializedValue(f.asInstanceOf[Any ⇒ Any]))
 
+  /**
+   * Change the attributes of this [[Source]] to the given ones and seal the list
+   * of attributes. This means that further calls will not be able to remove these
+   * attributes, but instead add new ones. Note that this
+   * operation has no effect on an empty Flow (because the attributes apply
+   * only to the contained processing stages).
+   */
   override def withAttributes(attr: Attributes): Sink[In, Mat] =
     new Sink(module.withAttributes(attr).nest())
 
+  /**
+   * Add the given attributes to this Source. Further calls to `withAttributes`
+   * will not remove these attributes. Note that this
+   * operation has no effect on an empty Flow (because the attributes apply
+   * only to the contained processing stages).
+   */
+  override def addAttributes(attr: Attributes): Sink[In, Mat] =
+    withAttributes(module.attributes and attr)
+
+  /**
+   * Add a ``name`` attribute to this Flow.
+   */
   override def named(name: String): Sink[In, Mat] = withAttributes(Attributes.name(name))
 
   /** Converts this Scala DSL element to it's Java DSL counterpart. */
diff --git a/akka-stream/src/main/scala/akka/stream/scaladsl/Source.scala b/akka-stream/src/main/scala/akka/stream/scaladsl/Source.scala
index cb648c947d..82586f5b99 100644
--- a/akka-stream/src/main/scala/akka/stream/scaladsl/Source.scala
+++ b/akka-stream/src/main/scala/akka/stream/scaladsl/Source.scala
@@ -110,13 +110,26 @@ final class Source[+Out, +Mat](private[stream] override val module: Module)
   def runForeach(f: Out ⇒ Unit)(implicit materializer: Materializer): Future[Unit] = runWith(Sink.foreach(f))
 
   /**
-   * Nests the current Source and returns a Source with the given Attributes
-   * @param attr the attributes to add
-   * @return a new Source with the added attributes
+   * Change the attributes of this [[Source]] to the given ones and seal the list
+   * of attributes. This means that further calls will not be able to remove these
+   * attributes, but instead add new ones. Note that this
+   * operation has no effect on an empty Flow (because the attributes apply
+   * only to the contained processing stages).
    */
   override def withAttributes(attr: Attributes): Repr[Out] =
-    new Source(module.withAttributes(attr).nest()) // User API
+    new Source(module.withAttributes(attr).nest())
 
+  /**
+   * Add the given attributes to this Source. Further calls to `withAttributes`
+   * will not remove these attributes. Note that this
+   * operation has no effect on an empty Flow (because the attributes apply
+   * only to the contained processing stages).
+   */
+  override def addAttributes(attr: Attributes): Repr[Out] = withAttributes(module.attributes and attr)
+
+  /**
+   * Add a ``name`` attribute to this Flow.
+   */
   override def named(name: String): Repr[Out] = withAttributes(Attributes.name(name))
 
   /** Converts this Scala DSL element to it's Java DSL counterpart. */