diff --git a/.gitignore b/.gitignore
index 86fb982..41ed2bf 100644
--- a/.gitignore
+++ b/.gitignore
@@ -5,3 +5,4 @@ target
 /.settings
 /.target
 /bin
+benchmark/JmhBench.scala
\ No newline at end of file
diff --git a/benchmark/README.md b/benchmark/README.md
index eb68ef9..c7d3491 100644
--- a/benchmark/README.md
+++ b/benchmark/README.md
@@ -6,11 +6,9 @@ Because the benchmarking is **very computationally expensive** it should be done
 
 ## Code generation step
 
-1. Run `sbt console`
-
-2. If the `JmhBench.scala` file already exists, delete it.
+1. Make sure the parent project has been built by running `sbt package` in it.
 
-3. Enter `bench.codegen.Generate.jmhBench()` to generate the `JmhBench.scala` file.
+2. `cd` to the benchmark project and run `sbt generateJmh`
 
 ## Benchmarking step
 
diff --git a/benchmark/build.sbt b/benchmark/build.sbt
index 5365275..5a7420f 100644
--- a/benchmark/build.sbt
+++ b/benchmark/build.sbt
@@ -1,10 +1,15 @@
 enablePlugins(JmhPlugin)
 
+val generateJmh = TaskKey[Unit]("generateJmh", "Generates JMH benchmark sources.")
+
 lazy val root = (project in file(".")).settings(
   name := "java8-compat-bench",
-  scalaVersion := "2.11.7",
-  crossScalaVersions := List("2.11.7" /* TODO, "2.12.0-M3"*/),
+  scalaVersion := "2.11.8",
+  crossScalaVersions := List("2.11.8" /* TODO, "2.12.0-M4"*/),
   organization := "org.scala-lang.modules",
   version := "0.6.0-SNAPSHOT",
-  unmanagedJars in Compile ++= Seq(baseDirectory.value / "../target/scala-2.11/scala-java8-compat_2.11-0.6.0-SNAPSHOT.jar")
+  unmanagedJars in Compile ++= Seq(baseDirectory.value / "../target/scala-2.11/scala-java8-compat_2.11-0.8.0-SNAPSHOT.jar"),
+  // This would be nicer but sbt-jmh doesn't like it:
+  //unmanagedClasspath in Compile += Attributed.blank(baseDirectory.value / "../target/scala-2.11/classes"),
+  generateJmh := (runMain in Compile).toTask(" bench.codegen.GenJmhBench").value
 )
diff --git a/benchmark/project/plugins.sbt b/benchmark/project/plugins.sbt
index c5220d0..f5319fb 100644
--- a/benchmark/project/plugins.sbt
+++ b/benchmark/project/plugins.sbt
@@ -1 +1 @@
-addSbtPlugin("pl.project13.scala" % "sbt-jmh" % "0.2.5")
+addSbtPlugin("pl.project13.scala" % "sbt-jmh" % "0.2.6")
diff --git a/benchmark/src/main/scala/bench/CodeGen.scala b/benchmark/src/main/scala/bench/CodeGen.scala
index 4e206ce..09a1af3 100644
--- a/benchmark/src/main/scala/bench/CodeGen.scala
+++ b/benchmark/src/main/scala/bench/CodeGen.scala
@@ -232,3 +232,11 @@ object Generator {
     }
   }
 }
+
+object GenJmhBench {
+  def main(args: Array[String]): Unit = {
+    val f = new java.io.File("JmhBench.scala")
+    f.delete()
+    Generator.jmhBench(f)
+  }
+}
diff --git a/benchmark/src/main/scala/bench/CollectionSource.scala b/benchmark/src/main/scala/bench/CollectionSource.scala
index 689aa42..5f40a33 100644
--- a/benchmark/src/main/scala/bench/CollectionSource.scala
+++ b/benchmark/src/main/scala/bench/CollectionSource.scala
@@ -25,30 +25,30 @@ package object generate {
   }
 
   object Pstep {
-    def i[CC](cc: CC)(implicit steppize: CC => MakesIntStepper): IntStepper =
+    def i[CC](cc: CC)(implicit steppize: CC => MakesStepper[IntStepper with EfficientSubstep]): IntStepper =
       steppize(cc).stepper
-    def s[CC](cc: CC)(implicit steppize: CC => MakesAnyStepper[String]): AnyStepper[String] =
+    def s[CC](cc: CC)(implicit steppize: CC => MakesStepper[AnyStepper[String] with EfficientSubstep]): AnyStepper[String] =
       steppize(cc).stepper
   }
 
   object Sstep {
-    def i[CC](cc: CC)(implicit steppize: CC => MakesIntSeqStepper): IntStepper =
+    def i[CC](cc: CC)(implicit steppize: CC => MakesStepper[IntStepper]): IntStepper =
       steppize(cc).stepper
-    def s[CC](cc: CC)(implicit steppize: CC => MakesAnySeqStepper[String]): AnyStepper[String] =
+    def s[CC](cc: CC)(implicit steppize: CC => MakesStepper[AnyStepper[String]]): AnyStepper[String] =
       steppize(cc).stepper
   }
 
   object PsStream {
-    def i[CC](cc: CC)(implicit steppize: CC => MakesIntStepper): IntStream =
+    def i[CC](cc: CC)(implicit steppize: CC => MakesStepper[IntStepper with EfficientSubstep]): IntStream =
       steppize(cc).stepper.parStream
-    def s[CC](cc: CC)(implicit steppize: CC => MakesAnyStepper[String]): Stream[String] =
+    def s[CC](cc: CC)(implicit steppize: CC => MakesStepper[AnyStepper[String] with EfficientSubstep]): Stream[String] =
       steppize(cc).stepper.parStream
   }
 
   object SsStream {
-    def i[CC](cc: CC)(implicit steppize: CC => MakesIntSeqStepper): IntStream =
+    def i[CC](cc: CC)(implicit steppize: CC => MakesStepper[IntStepper]): IntStream =
       steppize(cc).stepper.seqStream
-    def s[CC](cc: CC)(implicit steppize: CC => MakesAnySeqStepper[String]): Stream[String] =
+    def s[CC](cc: CC)(implicit steppize: CC => MakesStepper[AnyStepper[String]]): Stream[String] =
       steppize(cc).stepper.seqStream
   }
 
@@ -78,14 +78,14 @@ package object generate {
     // Iterator
     def iI(j: Int)(implicit x: CC[Int] => Iterator[Int]) = x(cI(j))
     // Steppers (second letter--s = sequential, p = parallel)
-    def tsI(j: Int)(implicit x: CC[Int] => MakesIntSeqStepper) = Sstep i cI(j)
-    def tpI(j: Int)(implicit x: CC[Int] => MakesIntStepper) = Pstep i cI(j)
+    def tsI(j: Int)(implicit x: CC[Int] => MakesStepper[IntStepper]) = Sstep i cI(j)
+    def tpI(j: Int)(implicit x: CC[Int] => MakesStepper[IntStepper with EfficientSubstep]) = Pstep i cI(j)
     // Streams
     def ssI(j: Int)(implicit x: CC[Int] => MakesSequentialStream[java.lang.Integer, IntStream]) = Sstream i cI(j)
     def spI(j: Int)(implicit x: CC[Int] => MakesParallelStream[java.lang.Integer, IntStream]) = Pstream i cI(j)
     // Streams via steppers
-    def zsI(j: Int)(implicit x: CC[Int] => MakesIntSeqStepper) = SsStream i cI(j)
-    def zpI(j: Int)(implicit x: CC[Int] => MakesIntStepper) = PsStream i cI(j)
+    def zsI(j: Int)(implicit x: CC[Int] => MakesStepper[IntStepper]) = SsStream i cI(j)
+    def zpI(j: Int)(implicit x: CC[Int] => MakesStepper[IntStepper with EfficientSubstep]) = PsStream i cI(j)
   }
 
   trait StringThingsOf[CC[_]] extends GenThingsOf[CC] {
@@ -95,14 +95,14 @@ package object generate {
     // Iterator
     def iS(j: Int)(implicit x: CC[String] => Iterator[String]) = x(cS(j))
     // Steppers (second letter--s = sequential, p = parallel)
-    def tsS(j: Int)(implicit x: CC[String] => MakesAnySeqStepper[String]) = Sstep s cS(j)
-    def tpS(j: Int)(implicit x: CC[String] => MakesAnyStepper[String]) = Pstep s cS(j)
+    def tsS(j: Int)(implicit x: CC[String] => MakesStepper[AnyStepper[String]]) = Sstep s cS(j)
+    def tpS(j: Int)(implicit x: CC[String] => MakesStepper[AnyStepper[String] with EfficientSubstep]) = Pstep s cS(j)
     // Streams
     def ssS(j: Int)(implicit x: CC[String] => MakesSequentialStream[String, Stream[String]]) = Sstream s cS(j)
     def spS(j: Int)(implicit x: CC[String] => MakesParallelStream[String, Stream[String]]) = Pstream s cS(j)
     // Streams via steppers
-    def zsS(j: Int)(implicit x: CC[String] => MakesAnySeqStepper[String]) = SsStream s cS(j)
-    def zpS(j: Int)(implicit x: CC[String] => MakesAnyStepper[String]) = PsStream s cS(j)
+    def zsS(j: Int)(implicit x: CC[String] => MakesStepper[AnyStepper[String]]) = SsStream s cS(j)
+    def zpS(j: Int)(implicit x: CC[String] => MakesStepper[AnyStepper[String] with EfficientSubstep]) = PsStream s cS(j)
   }
 
   trait ThingsOf[CC[_]] extends IntThingsOf[CC] with StringThingsOf[CC] {}
diff --git a/build.sbt b/build.sbt
index 9c0d927..c2da864 100644
--- a/build.sbt
+++ b/build.sbt
@@ -109,6 +109,6 @@ lazy val root = (project in file(".")).
     """|import scala.concurrent._
        |import ExecutionContext.Implicits.global
        |import java.util.concurrent.{CompletionStage,CompletableFuture}
-       |import scala.compat.java8.FutureConverter._
+       |import scala.compat.java8.FutureConverters._
        |""".stripMargin
   )