Merge branch 'master' into bump-zinc

179 files changed, 640 insertions, 354 deletions

diff --git a/build.sc b/build.sc
index bffec005..f11a3caf 100755
--- a/build.sc
+++ b/build.sc
@@ -27,7 +27,7 @@ trait MillPublishModule extends PublishModule{
   def javacOptions = Seq("-source", "1.8", "-target", "1.8")
 }
 trait MillApiModule extends MillPublishModule with ScalaModule{
-  def scalaVersion = T{ "2.12.6" }
+  def scalaVersion = T{ "2.12.8" }
   def compileIvyDeps = Agg(ivy"com.lihaoyi::acyclic:0.1.7")
   def scalacOptions = Seq("-P:acyclic:force")
   def scalacPluginIvyDeps = Agg(ivy"com.lihaoyi::acyclic:0.1.7")
@@ -105,7 +105,7 @@ object main extends MillModule {
   }
 
   object moduledefs extends MillPublishModule with ScalaModule{
-    def scalaVersion = T{ "2.12.6" }
+    def scalaVersion = T{ "2.12.8" }
     def ivyDeps = Agg(
       ivy"org.scala-lang:scala-compiler:${scalaVersion()}",
       ivy"com.lihaoyi::sourcecode:0.1.4",
diff --git a/ci/shared.sc b/ci/shared.sc
index 2f133486..a496fd1f 100644
--- a/ci/shared.sc
+++ b/ci/shared.sc
@@ -74,7 +74,7 @@ def generateEval(dir: Path) = {
     s"""package mill.main
        |import mill.eval.Evaluator
        |import mill.define.Task
-       |import mill.util.Strict.Agg
+       |import mill.api.Strict.Agg
        |class EvalGenerated(evaluator: Evaluator) {
        |  type TT[+X] = Task[X]
        |  ${(1 to 22).map(generate).mkString("\n")}
diff --git a/contrib/buildinfo/src/mill/contrib/BuildInfo.scala b/contrib/buildinfo/src/BuildInfo.scala
index 1c8d9d9e..1c8d9d9e 100644
--- a/contrib/buildinfo/src/mill/contrib/BuildInfo.scala
+++ b/contrib/buildinfo/src/BuildInfo.scala
diff --git a/contrib/buildinfo/test/src/mill/contrib/BuildInfoTests.scala b/contrib/buildinfo/test/src/BuildInfoTests.scala
index 4293bba7..4293bba7 100644
--- a/contrib/buildinfo/test/src/mill/contrib/BuildInfoTests.scala
+++ b/contrib/buildinfo/test/src/BuildInfoTests.scala
diff --git a/contrib/scalapblib/src/mill/contrib/scalapblib/ScalaPBModule.scala b/contrib/scalapblib/src/ScalaPBModule.scala
index db5c5c8b..57bfdd40 100644
--- a/contrib/scalapblib/src/mill/contrib/scalapblib/ScalaPBModule.scala
+++ b/contrib/scalapblib/src/ScalaPBModule.scala
@@ -7,7 +7,7 @@ import mill.define.Sources
 import mill.api.PathRef
 import mill.scalalib.Lib.resolveDependencies
 import mill.scalalib._
-import mill.util.Loose
+import mill.api.Loose
 
 trait ScalaPBModule extends ScalaModule {
 
diff --git a/contrib/scalapblib/src/mill/contrib/scalapblib/ScalaPBWorker.scala b/contrib/scalapblib/src/ScalaPBWorker.scala
index 125cd3fd..125cd3fd 100644
--- a/contrib/scalapblib/src/mill/contrib/scalapblib/ScalaPBWorker.scala
+++ b/contrib/scalapblib/src/ScalaPBWorker.scala
diff --git a/contrib/scalapblib/test/src/mill/contrib/scalapblib/TutorialTests.scala b/contrib/scalapblib/test/src/TutorialTests.scala
index fe0ce8d5..fe0ce8d5 100644
--- a/contrib/scalapblib/test/src/mill/contrib/scalapblib/TutorialTests.scala
+++ b/contrib/scalapblib/test/src/TutorialTests.scala
diff --git a/contrib/testng/src/mill/testng/ResultEvent.java b/contrib/testng/src/ResultEvent.java
index 6e2a50d6..6e2a50d6 100644
--- a/contrib/testng/src/mill/testng/ResultEvent.java
+++ b/contrib/testng/src/ResultEvent.java
diff --git a/contrib/testng/src/mill/testng/TestNGFramework.java b/contrib/testng/src/TestNGFramework.java
index 6e993fcc..6e993fcc 100644
--- a/contrib/testng/src/mill/testng/TestNGFramework.java
+++ b/contrib/testng/src/TestNGFramework.java
diff --git a/contrib/testng/src/mill/testng/TestNGInstance.java b/contrib/testng/src/TestNGInstance.java
index 4cf274d3..4cf274d3 100644
--- a/contrib/testng/src/mill/testng/TestNGInstance.java
+++ b/contrib/testng/src/TestNGInstance.java
diff --git a/contrib/testng/src/mill/testng/TestNGRunner.java b/contrib/testng/src/TestNGRunner.java
index 0ad05f76..0ad05f76 100644
--- a/contrib/testng/src/mill/testng/TestNGRunner.java
+++ b/contrib/testng/src/TestNGRunner.java
diff --git a/contrib/tut/src/mill/contrib/tut/TutModule.scala b/contrib/tut/src/TutModule.scala
index e51a8d7b..e51a8d7b 100644
--- a/contrib/tut/src/mill/contrib/tut/TutModule.scala
+++ b/contrib/tut/src/TutModule.scala
diff --git a/contrib/tut/test/src/mill/contrib/tut/TutTests.scala b/contrib/tut/test/src/TutTests.scala
index 468654bb..468654bb 100644
--- a/contrib/tut/test/src/mill/contrib/tut/TutTests.scala
+++ b/contrib/tut/test/src/TutTests.scala
diff --git a/contrib/twirllib/src/mill/twirllib/TwirlModule.scala b/contrib/twirllib/src/TwirlModule.scala
index 328afc47..985765fc 100644
--- a/contrib/twirllib/src/mill/twirllib/TwirlModule.scala
+++ b/contrib/twirllib/src/TwirlModule.scala
@@ -6,7 +6,7 @@ import mill.define.Sources
 import mill.api.PathRef
 import mill.scalalib.Lib.resolveDependencies
 import mill.scalalib._
-import mill.util.Loose
+import mill.api.Loose
 
 import scala.io.Codec
 import scala.util.Properties
diff --git a/contrib/twirllib/src/mill/twirllib/TwirlWorker.scala b/contrib/twirllib/src/TwirlWorker.scala
index 09376a6f..09376a6f 100644
--- a/contrib/twirllib/src/mill/twirllib/TwirlWorker.scala
+++ b/contrib/twirllib/src/TwirlWorker.scala
diff --git a/contrib/twirllib/test/src/mill/twirllib/HelloWorldTests.scala b/contrib/twirllib/test/src/HelloWorldTests.scala
index 71f25ff4..71f25ff4 100644
--- a/contrib/twirllib/test/src/mill/twirllib/HelloWorldTests.scala
+++ b/contrib/twirllib/test/src/HelloWorldTests.scala
diff --git a/docs/example-1/foo/src/foo/Example.scala b/docs/example-1/foo/src/Example.scala
index f84f91f9..f84f91f9 100644
--- a/docs/example-1/foo/src/foo/Example.scala
+++ b/docs/example-1/foo/src/Example.scala
diff --git a/docs/example-2/foo/src/foo/Example.scala b/docs/example-2/foo/src/Example.scala
index f84f91f9..f84f91f9 100644
--- a/docs/example-2/foo/src/foo/Example.scala
+++ b/docs/example-2/foo/src/Example.scala
diff --git a/docs/pages/9 - Contrib Modules.md b/docs/pages/9 - Contrib Modules.md
index 4d811cde..cf63039a 100644
--- a/docs/pages/9 - Contrib Modules.md
+++ b/docs/pages/9 - Contrib Modules.md
@@ -276,18 +276,21 @@ Project home: https://github.com/lefou/mill-osgi
 #### Quickstart
 
 ```scala
-import $ivy.`de.tototec::de.tobiasroeser.mill.osgi:0.0.2`
+import mill._, mill.scalalib._
+import $ivy.`de.tototec::de.tobiasroeser.mill.osgi:0.0.5`
 import de.tobiasroeser.mill.osgi._
 
 object project extends ScalaModule with OsgiBundleModule {
 
   def bundleSymbolicName = "com.example.project"
 
-  def osgiHeaders = T{ osgiHeaders().copy(
+  def osgiHeaders = T{ super.osgiHeaders().copy(
     `Export-Package`   = Seq("com.example.api"),
     `Bundle-Activator` = Some("com.example.internal.Activator")
   )}
 
+  // other settings ...
+
 }
 ```
 
diff --git a/integration/test/resources/large-project/build.sc b/integration/test/resources/large-project/build.sc
new file mode 100644
index 00000000..27844c90
--- /dev/null
+++ b/integration/test/resources/large-project/build.sc
@@ -0,0 +1,293 @@
+import mill._, scalalib._
+
+trait TModule extends SbtModule {
+  def scalaVersion = "2.12.7"
+}
+
+object foo extends Module {
+  object common extends Module {
+    object one extends TModule {
+      def moduleDeps = Seq()
+    }
+    object two extends TModule {
+      def moduleDeps = Seq(foo.common.one)
+    }
+    object three extends TModule {
+      def moduleDeps = Seq(foo.common.two)
+    }
+  }
+  object domain extends Module {
+    object one extends TModule {
+      def moduleDeps = Seq(foo.common.one)
+    }
+    object two extends TModule {
+      def moduleDeps = Seq(foo.domain.one)
+    }
+    object three extends TModule {
+      def moduleDeps = Seq(foo.domain.two)
+    }
+  }
+  object server extends Module {
+    object one extends TModule {
+      def moduleDeps = Seq(foo.domain.three)
+    }
+    object two extends TModule {
+      def moduleDeps = Seq(foo.server.one)
+    }
+    object three extends TModule {
+      def moduleDeps = Seq(foo.server.two)
+    }
+  }
+}
+
+object bar extends Module {
+  object common extends Module {
+    object one extends TModule {
+      def moduleDeps = Seq(foo.common.three)
+    }
+    object two extends TModule {
+      def moduleDeps = Seq(bar.common.one)
+    }
+    object three extends TModule {
+      def moduleDeps = Seq(bar.common.two)
+    }
+  }
+  object domain extends Module {
+    object one extends TModule {
+      def moduleDeps = Seq(foo.domain.three)
+    }
+    object two extends TModule {
+      def moduleDeps = Seq(bar.domain.one)
+    }
+    object three extends TModule {
+      def moduleDeps = Seq(bar.domain.two)
+    }
+  }
+  object server extends Module {
+    object one extends TModule {
+      def moduleDeps = Seq(foo.server.one)
+    }
+    object two extends TModule {
+      def moduleDeps = Seq(bar.server.one)
+    }
+    object three extends TModule {
+      def moduleDeps = Seq(bar.server.two)
+    }
+  }
+}
+
+object ham extends Module {
+  object common extends Module {
+    object one extends TModule {
+      def moduleDeps = Seq(bar.common.one)
+    }
+    object two extends TModule {
+      def moduleDeps = Seq(bar.common.two)
+    }
+    object three extends TModule {
+      def moduleDeps = Seq(bar.common.three)
+    }
+  }
+  object domain extends Module {
+    object one extends TModule {
+      def moduleDeps = Seq(bar.domain.three)
+    }
+    object two extends TModule {
+      def moduleDeps = Seq(bar.domain.two, ham.common.three)
+    }
+    object three extends TModule {
+      def moduleDeps = Seq(bar.domain.two)
+    }
+  }
+  object server extends Module {
+    object one extends TModule {
+      def moduleDeps = Seq()
+    }
+    object two extends TModule {
+      def moduleDeps = Seq()
+    }
+    object three extends TModule {
+      def moduleDeps = Seq()
+    }
+  }
+}
+
+object eggs extends Module {
+  object common extends Module {
+    object one extends TModule {
+      def moduleDeps = Seq()
+    }
+    object two extends TModule {
+      def moduleDeps = Seq()
+    }
+    object three extends TModule {
+      def moduleDeps = Seq()
+    }
+  }
+  object domain extends Module {
+    object one extends TModule {
+      def moduleDeps = Seq()
+    }
+    object two extends TModule {
+      def moduleDeps = Seq()
+    }
+    object three extends TModule {
+      def moduleDeps = Seq()
+    }
+  }
+  object server extends Module {
+    object one extends TModule {
+      def moduleDeps = Seq()
+    }
+    object two extends TModule {
+      def moduleDeps = Seq()
+    }
+    object three extends TModule {
+      def moduleDeps = Seq()
+    }
+  }
+}
+
+object salt extends Module {
+  object common extends Module {
+    object one extends TModule {
+      def moduleDeps = Seq()
+    }
+    object two extends TModule {
+      def moduleDeps = Seq()
+    }
+    object three extends TModule {
+      def moduleDeps = Seq()
+    }
+  }
+  object domain extends Module {
+    object one extends TModule {
+      def moduleDeps = Seq()
+    }
+    object two extends TModule {
+      def moduleDeps = Seq()
+    }
+    object three extends TModule {
+      def moduleDeps = Seq()
+    }
+  }
+  object server extends Module {
+    object one extends TModule {
+      def moduleDeps = Seq()
+    }
+    object two extends TModule {
+      def moduleDeps = Seq()
+    }
+    object three extends TModule {
+      def moduleDeps = Seq()
+    }
+  }
+}
+
+object pepper extends Module {
+  object common extends Module {
+    object one extends TModule {
+      def moduleDeps = Seq()
+    }
+    object two extends TModule {
+      def moduleDeps = Seq()
+    }
+    object three extends TModule {
+      def moduleDeps = Seq()
+    }
+  }
+  object domain extends Module {
+    object one extends TModule {
+      def moduleDeps = Seq()
+    }
+    object two extends TModule {
+      def moduleDeps = Seq()
+    }
+    object three extends TModule {
+      def moduleDeps = Seq()
+    }
+  }
+  object server extends Module {
+    object one extends TModule {
+      def moduleDeps = Seq()
+    }
+    object two extends TModule {
+      def moduleDeps = Seq()
+    }
+    object three extends TModule {
+      def moduleDeps = Seq()
+    }
+  }
+}
+
+object oregano extends Module {
+  object common extends Module {
+    object one extends TModule {
+      def moduleDeps = Seq()
+    }
+    object two extends TModule {
+      def moduleDeps = Seq()
+    }
+    object three extends TModule {
+      def moduleDeps = Seq()
+    }
+  }
+  object domain extends Module {
+    object one extends TModule {
+      def moduleDeps = Seq()
+    }
+    object two extends TModule {
+      def moduleDeps = Seq()
+    }
+    object three extends TModule {
+      def moduleDeps = Seq()
+    }
+  }
+  object server extends Module {
+    object one extends TModule {
+      def moduleDeps = Seq()
+    }
+    object two extends TModule {
+      def moduleDeps = Seq()
+    }
+    object three extends TModule {
+      def moduleDeps = Seq()
+    }
+  }
+}
+
+object rosmarin extends Module {
+  object common extends Module {
+    object one extends TModule {
+      def moduleDeps = Seq()
+    }
+    object two extends TModule {
+      def moduleDeps = Seq()
+    }
+    object three extends TModule {
+      def moduleDeps = Seq()
+    }
+  }
+  object domain extends Module {
+    object one extends TModule {
+      def moduleDeps = Seq()
+    }
+    object two extends TModule {
+      def moduleDeps = Seq()
+    }
+    object three extends TModule {
+      def moduleDeps = Seq()
+    }
+  }
+  object server extends Module {
+    object one extends TModule {
+      def moduleDeps = Seq()
+    }
+    object two extends TModule {
+      def moduleDeps = Seq()
+    }
+    object three extends TModule {
+      def moduleDeps = Seq()
+    }
+  }
+}
diff --git a/integration/test/resources/large-project/foo/common/one/src/main/scala/foo/common/one/Main.scala b/integration/test/resources/large-project/foo/common/one/src/main/scala/foo/common/one/Main.scala
new file mode 100644
index 00000000..4fd74836
--- /dev/null
+++ b/integration/test/resources/large-project/foo/common/one/src/main/scala/foo/common/one/Main.scala
@@ -0,0 +1,5 @@
+package foo.common.one
+
+object Main extends App {
+  println("large-project")
+}
diff --git a/integration/test/src/mill/integration/AcyclicTests.scala b/integration/test/src/AcyclicTests.scala
index 145c106d..145c106d 100644
--- a/integration/test/src/mill/integration/AcyclicTests.scala
+++ b/integration/test/src/AcyclicTests.scala
diff --git a/integration/test/src/mill/integration/AmmoniteTests.scala b/integration/test/src/AmmoniteTests.scala
index 5851a393..5851a393 100644
--- a/integration/test/src/mill/integration/AmmoniteTests.scala
+++ b/integration/test/src/AmmoniteTests.scala
diff --git a/integration/test/src/mill/integration/BetterFilesTests.scala b/integration/test/src/BetterFilesTests.scala
index bdbaa2e3..bdbaa2e3 100644
--- a/integration/test/src/mill/integration/BetterFilesTests.scala
+++ b/integration/test/src/BetterFilesTests.scala
diff --git a/integration/test/src/mill/integration/CaffeineTests.scala b/integration/test/src/CaffeineTests.scala
index 56c66b21..56c66b21 100644
--- a/integration/test/src/mill/integration/CaffeineTests.scala
+++ b/integration/test/src/CaffeineTests.scala
diff --git a/integration/test/src/mill/integration/DocAnnotationsTests.scala b/integration/test/src/DocAnnotationsTests.scala
index 4d7ef11b..4d7ef11b 100644
--- a/integration/test/src/mill/integration/DocAnnotationsTests.scala
+++ b/integration/test/src/DocAnnotationsTests.scala
diff --git a/integration/test/src/mill/integration/IntegrationTestSuite.scala b/integration/test/src/IntegrationTestSuite.scala
index ca041eea..ca041eea 100644
--- a/integration/test/src/mill/integration/IntegrationTestSuite.scala
+++ b/integration/test/src/IntegrationTestSuite.scala
diff --git a/integration/test/src/mill/integration/JawnTests.scala b/integration/test/src/JawnTests.scala
index eafd1009..eafd1009 100644
--- a/integration/test/src/mill/integration/JawnTests.scala
+++ b/integration/test/src/JawnTests.scala
diff --git a/integration/test/src/LargeProjectTests.scala b/integration/test/src/LargeProjectTests.scala
new file mode 100644
index 00000000..e20bc932
--- /dev/null
+++ b/integration/test/src/LargeProjectTests.scala
@@ -0,0 +1,19 @@
+package mill.integration
+
+import mill.util.ScriptTestSuite
+import utest._
+
+class LargeProjectTests(fork: Boolean)
+  extends ScriptTestSuite(fork) {
+  def workspaceSlug: String = "large-project"
+  def scriptSourcePath: os.Path = os.pwd / 'integration / 'test / 'resources / workspaceSlug
+
+  val tests = Tests{
+    initWorkspace()
+    'test - {
+
+      assert(eval("foo.common.one.compile"))
+    }
+
+  }
+}
diff --git a/integration/test/src/mill/integration/PlayJsonTests.scala b/integration/test/src/PlayJsonTests.scala
index 262dcb36..262dcb36 100644
--- a/integration/test/src/mill/integration/PlayJsonTests.scala
+++ b/integration/test/src/PlayJsonTests.scala
diff --git a/integration/test/src/mill/integration/UpickleTests.scala b/integration/test/src/UpickleTests.scala
index 133188d3..133188d3 100644
--- a/integration/test/src/mill/integration/UpickleTests.scala
+++ b/integration/test/src/UpickleTests.scala
diff --git a/integration/test/src/mill/integration/forked/Tests.scala b/integration/test/src/forked/Tests.scala
index 41844b58..b31042bb 100644
--- a/integration/test/src/mill/integration/forked/Tests.scala
+++ b/integration/test/src/forked/Tests.scala
@@ -3,6 +3,7 @@ package mill.integration.forked
 object AcyclicTests extends mill.integration.AcyclicTests(fork = true)
 object AmmoniteTests extends mill.integration.AmmoniteTests(fork = true)
 object BetterFilesTests extends mill.integration.BetterFilesTests(fork = true)
+object LargeProjectTests extends mill.integration.LargeProjectTests(fork = true)
 object JawnTests extends mill.integration.JawnTests(fork = true)
 object UpickleTests extends mill.integration.UpickleTests(fork = true)
 object PlayJsonTests extends mill.integration.PlayJsonTests(fork = true)
diff --git a/integration/test/src/mill/integration/local/Tests.scala b/integration/test/src/local/Tests.scala
index e95aac54..efc45b94 100644
--- a/integration/test/src/mill/integration/local/Tests.scala
+++ b/integration/test/src/local/Tests.scala
@@ -3,8 +3,9 @@ package mill.integration.local
 object AcyclicTests extends mill.integration.AcyclicTests(fork = false)
 object AmmoniteTests extends mill.integration.AmmoniteTests(fork = false)
 object BetterFilesTests extends mill.integration.BetterFilesTests(fork = false)
+object LargeProjectTests extends mill.integration.LargeProjectTests(fork = false)
 object JawnTests extends mill.integration.JawnTests(fork = false)
 object UpickleTests extends mill.integration.UpickleTests(fork = false)
 object PlayJsonTests extends mill.integration.PlayJsonTests(fork = false)
 object CaffeineTests extends mill.integration.CaffeineTests(fork = false)
-object DocAnnotationsTests extends mill.integration.DocAnnotationsTests(fork = false)
\ No newline at end of file
+object DocAnnotationsTests extends mill.integration.DocAnnotationsTests(fork = false)
diff --git a/main/api/src/mill/api/KeyedLockedCache.scala b/main/api/src/mill/api/KeyedLockedCache.scala
new file mode 100644
index 00000000..47fdd888
--- /dev/null
+++ b/main/api/src/mill/api/KeyedLockedCache.scala
@@ -0,0 +1,44 @@
+package mill.api
+
+/**
+  * A combination lock & cache; users provide a key, value-factory, and a
+  * body function to be called with the value. [[KeyedLockedCache]] ensures that
+  * the body function is called with the computed/cached value sequentially.
+  */
+trait KeyedLockedCache[T]{
+  def withCachedValue[V](key: Long)(f: => T)(f2: T => V): V
+}
+
+object KeyedLockedCache{
+  class RandomBoundedCache[T](hotParallelism: Int, coldCacheSize: Int) extends KeyedLockedCache[T]{
+    private[this] val random = new scala.util.Random(313373)
+    val available = new java.util.concurrent.Semaphore(hotParallelism)
+
+    // Awful asymptotic complexity, but our caches are tiny n < 10 so it doesn't matter
+    var cache = Array.fill[Option[(Long, T)]](coldCacheSize)(None)
+
+    def withCachedValue[V](key: Long)(f: => T)(f2: T => V): V = {
+      available.acquire()
+      val pickedValue = synchronized{
+        cache.indexWhere(_.exists(_._1 == key)) match {
+          case -1 => f
+          case i =>
+            val (k, v) = cache(i).get
+            cache(i) = None
+            v
+        }
+      }
+      val result = f2(pickedValue)
+      synchronized{
+        cache.indexWhere(_.isEmpty) match{
+          // Random eviction #YOLO
+          case -1 => cache(random.nextInt(cache.length)) = Some((key, pickedValue))
+          case i => cache(i) = Some((key, pickedValue))
+        }
+      }
+
+      available.release()
+      result
+    }
+  }
+}
diff --git a/main/client/src/mill/main/client/InputPumper.java b/main/client/src/InputPumper.java
index 5205be0b..5205be0b 100644
--- a/main/client/src/mill/main/client/InputPumper.java
+++ b/main/client/src/InputPumper.java
diff --git a/main/client/src/mill/main/client/Lock.java b/main/client/src/Lock.java
index 6e5f18b0..6e5f18b0 100644
--- a/main/client/src/mill/main/client/Lock.java
+++ b/main/client/src/Lock.java
diff --git a/main/client/src/mill/main/client/Locked.java b/main/client/src/Locked.java
index e6ad3d63..e6ad3d63 100644
--- a/main/client/src/mill/main/client/Locked.java
+++ b/main/client/src/Locked.java
diff --git a/main/client/src/mill/main/client/Locks.java b/main/client/src/Locks.java
index 64259293..64259293 100644
--- a/main/client/src/mill/main/client/Locks.java
+++ b/main/client/src/Locks.java
diff --git a/main/client/src/mill/main/client/MillClientMain.java b/main/client/src/MillClientMain.java
index 3857caff..3857caff 100644
--- a/main/client/src/mill/main/client/MillClientMain.java
+++ b/main/client/src/MillClientMain.java
diff --git a/main/client/src/mill/main/client/ProxyOutputStream.java b/main/client/src/ProxyOutputStream.java
index 339e0150..339e0150 100644
--- a/main/client/src/mill/main/client/ProxyOutputStream.java
+++ b/main/client/src/ProxyOutputStream.java
diff --git a/main/client/src/mill/main/client/ProxyStreamPumper.java b/main/client/src/ProxyStreamPumper.java
index 977323f3..977323f3 100644
--- a/main/client/src/mill/main/client/ProxyStreamPumper.java
+++ b/main/client/src/ProxyStreamPumper.java
diff --git a/main/client/src/mill/main/client/Util.java b/main/client/src/Util.java
index 54361734..54361734 100644
--- a/main/client/src/mill/main/client/Util.java
+++ b/main/client/src/Util.java
diff --git a/main/client/test/src/mill/main/client/ClientTests.java b/main/client/test/src/ClientTests.java
index f3fcf154..f3fcf154 100644
--- a/main/client/test/src/mill/main/client/ClientTests.java
+++ b/main/client/test/src/ClientTests.java
diff --git a/main/core/src/mill/define/Applicative.scala b/main/core/src/define/Applicative.scala
index 5e63b1cc..5e63b1cc 100644
--- a/main/core/src/mill/define/Applicative.scala
+++ b/main/core/src/define/Applicative.scala
diff --git a/main/core/src/mill/define/BaseModule.scala b/main/core/src/define/BaseModule.scala
index cd79f73e..cd79f73e 100644
--- a/main/core/src/mill/define/BaseModule.scala
+++ b/main/core/src/define/BaseModule.scala
diff --git a/main/core/src/mill/define/Caller.scala b/main/core/src/define/Caller.scala
index 6d2d4d1d..6d2d4d1d 100644
--- a/main/core/src/mill/define/Caller.scala
+++ b/main/core/src/define/Caller.scala
diff --git a/main/core/src/mill/define/Cross.scala b/main/core/src/define/Cross.scala
index aa730e0d..aa730e0d 100644
--- a/main/core/src/mill/define/Cross.scala
+++ b/main/core/src/define/Cross.scala
diff --git a/main/core/src/mill/define/Ctx.scala b/main/core/src/define/Ctx.scala
index c21e53b4..c21e53b4 100644
--- a/main/core/src/mill/define/Ctx.scala
+++ b/main/core/src/define/Ctx.scala
diff --git a/main/core/src/mill/define/Discover.scala b/main/core/src/define/Discover.scala
index f0c668e6..c7dab54c 100644
--- a/main/core/src/mill/define/Discover.scala
+++ b/main/core/src/define/Discover.scala
@@ -79,9 +79,12 @@ object Discover {
       }
       if overridesRoutes.nonEmpty
     } yield {
+      // by wrapping the `overridesRoutes` in a lambda function we kind of work around
+      // the problem of generating a *huge* macro method body that finally exceeds the
+      // JVM's maximum allowed method size
+      val overridesLambda = q"(() => $overridesRoutes)()"
       val lhs =  q"classOf[${discoveredModuleType.typeSymbol.asClass}]"
-      val rhs = q"scala.Seq[(Int, mill.util.Router.EntryPoint[_])](..$overridesRoutes)"
-      q"$lhs -> $rhs"
+      q"$lhs -> $overridesLambda"
     }
 
     c.Expr[Discover[T]](q"mill.define.Discover(scala.collection.immutable.Map(..$mapping))")
diff --git a/main/core/src/mill/define/Graph.scala b/main/core/src/define/Graph.scala
index 3119f2fb..5b29bd7b 100644
--- a/main/core/src/mill/define/Graph.scala
+++ b/main/core/src/define/Graph.scala
@@ -2,7 +2,7 @@ package mill.define
 
 import mill.eval.Tarjans
 import mill.util.MultiBiMap
-import mill.util.Strict.Agg
+import mill.api.Strict.Agg
 
 object Graph {
 
diff --git a/main/core/src/mill/define/Module.scala b/main/core/src/define/Module.scala
index a8fc5be7..a8fc5be7 100644
--- a/main/core/src/mill/define/Module.scala
+++ b/main/core/src/define/Module.scala
diff --git a/main/core/src/mill/define/Task.scala b/main/core/src/define/Task.scala
index a464bf18..a464bf18 100644
--- a/main/core/src/mill/define/Task.scala
+++ b/main/core/src/define/Task.scala
diff --git a/main/core/src/mill/eval/Evaluator.scala b/main/core/src/eval/Evaluator.scala
index 8709064e..dbaf9433 100644
--- a/main/core/src/mill/eval/Evaluator.scala
+++ b/main/core/src/eval/Evaluator.scala
@@ -10,7 +10,7 @@ import mill.define.{Ctx => _, _}
 import mill.api.Result.OuterStack
 import mill.util
 import mill.util._
-import mill.util.Strict.Agg
+import mill.api.Strict.Agg
 
 import scala.collection.mutable
 import scala.util.control.NonFatal
diff --git a/main/core/src/mill/eval/Tarjans.scala b/main/core/src/eval/Tarjans.scala
index ade335a9..ade335a9 100644
--- a/main/core/src/mill/eval/Tarjans.scala
+++ b/main/core/src/eval/Tarjans.scala
diff --git a/main/core/src/mill/eval/package.scala b/main/core/src/eval/package.scala
index 433f9074..433f9074 100644
--- a/main/core/src/mill/eval/package.scala
+++ b/main/core/src/eval/package.scala
diff --git a/main/core/src/mill/util/AggWrapper.scala b/main/core/src/mill/util/AggWrapper.scala
deleted file mode 100644
index 6c107875..00000000
--- a/main/core/src/mill/util/AggWrapper.scala
+++ /dev/null
@@ -1,119 +0,0 @@
-package mill.util
-
-
-
-import scala.collection.mutable
-object Strict extends AggWrapper(true)
-object Loose extends AggWrapper(false)
-sealed class AggWrapper(strictUniqueness: Boolean){
-  /**
-    * A collection with enforced uniqueness, fast contains and deterministic
-    * ordering. Raises an exception if a duplicate is found; call
-    * `toSeq.distinct` if you explicitly want to make it swallow duplicates
-    */
-  trait Agg[V] extends TraversableOnce[V]{
-    def contains(v: V): Boolean
-    def items: Iterator[V]
-    def indexed: IndexedSeq[V]
-    def flatMap[T](f: V => TraversableOnce[T]): Agg[T]
-    def map[T](f: V => T): Agg[T]
-    def filter(f: V => Boolean): Agg[V]
-    def withFilter(f: V => Boolean): Agg[V]
-    def collect[T](f: PartialFunction[V, T]): Agg[T]
-    def zipWithIndex: Agg[(V, Int)]
-    def reverse: Agg[V]
-    def zip[T](other: Agg[T]): Agg[(V, T)]
-    def ++[T >: V](other: TraversableOnce[T]): Agg[T]
-    def length: Int
-  }
-
-  object Agg{
-    def empty[V]: Agg[V] = new Agg.Mutable[V]
-    implicit def jsonFormat[T: upickle.default.ReadWriter]: upickle.default.ReadWriter[Agg[T]] =
-      upickle.default.readwriter[Seq[T]].bimap[Agg[T]](
-        _.toList,
-        Agg.from(_)
-      )
-
-    def apply[V](items: V*) = from(items)
-
-    implicit def from[V](items: TraversableOnce[V]): Agg[V] = {
-      val set = new Agg.Mutable[V]()
-      items.foreach(set.append)
-      set
-    }
-
-
-    class Mutable[V]() extends Agg[V]{
-
-      private[this] val set0 = mutable.LinkedHashSet.empty[V]
-      def contains(v: V) = set0.contains(v)
-      def append(v: V) = if (!contains(v)){
-        set0.add(v)
-
-      }else if (strictUniqueness){
-        throw new Exception("Duplicated item inserted into OrderedSet: " + v)
-      }
-      def appendAll(vs: Seq[V]) = vs.foreach(append)
-      def items = set0.iterator
-      def indexed: IndexedSeq[V] = items.toIndexedSeq
-      def set: collection.Set[V] = set0
-
-      def map[T](f: V => T): Agg[T] = {
-        val output = new Agg.Mutable[T]
-        for(i <- items) output.append(f(i))
-        output
-      }
-      def flatMap[T](f: V => TraversableOnce[T]): Agg[T] = {
-        val output = new Agg.Mutable[T]
-        for(i <- items) for(i0 <- f(i)) output.append(i0)
-        output
-      }
-      def filter(f: V => Boolean): Agg[V] = {
-        val output = new Agg.Mutable[V]
-        for(i <- items) if (f(i)) output.append(i)
-        output
-      }
-      def withFilter(f: V => Boolean): Agg[V] = filter(f)
-
-      def collect[T](f: PartialFunction[V, T]) = this.filter(f.isDefinedAt).map(x => f(x))
-
-      def zipWithIndex = {
-        var i = 0
-        this.map{ x =>
-          i += 1
-          (x, i-1)
-        }
-      }
-
-      def reverse = Agg.from(indexed.reverseIterator)
-
-      def zip[T](other: Agg[T]) = Agg.from(items.zip(other.items))
-      def ++[T >: V](other: TraversableOnce[T]) = Agg.from(items ++ other)
-      def length: Int = set0.size
-
-      // Members declared in scala.collection.GenTraversableOnce
-      def isTraversableAgain: Boolean = items.isTraversableAgain
-      def toIterator: Iterator[V] = items.toIterator
-      def toStream: Stream[V] = items.toStream
-
-      // Members declared in scala.collection.TraversableOnce
-      def copyToArray[B >: V](xs: Array[B], start: Int,len: Int): Unit = items.copyToArray(xs, start, len)
-      def exists(p: V => Boolean): Boolean = items.exists(p)
-      def find(p: V => Boolean): Option[V] = items.find(p)
-      def forall(p: V => Boolean): Boolean = items.forall(p)
-      def foreach[U](f: V => U): Unit = items.foreach(f)
-      def hasDefiniteSize: Boolean = items.hasDefiniteSize
-      def isEmpty: Boolean = items.isEmpty
-      def seq: scala.collection.TraversableOnce[V] = items
-      def toTraversable: Traversable[V] = items.toTraversable
-
-      override def hashCode() = items.map(_.hashCode()).sum
-      override def equals(other: Any) = other match{
-        case s: Agg[_] => items.sameElements(s.items)
-        case _ => super.equals(other)
-      }
-      override def toString = items.mkString("Agg(", ", ", ")")
-    }
-  }
-}
diff --git a/main/core/src/mill/util/EitherOps.scala b/main/core/src/util/EitherOps.scala
index da2552c8..da2552c8 100644
--- a/main/core/src/mill/util/EitherOps.scala
+++ b/main/core/src/util/EitherOps.scala
diff --git a/main/core/src/mill/util/EnclosingClass.scala b/main/core/src/util/EnclosingClass.scala
index a69cc525..a69cc525 100644
--- a/main/core/src/mill/util/EnclosingClass.scala
+++ b/main/core/src/util/EnclosingClass.scala
diff --git a/main/core/src/mill/util/JsonFormatters.scala b/main/core/src/util/JsonFormatters.scala
index 830782c6..830782c6 100644
--- a/main/core/src/mill/util/JsonFormatters.scala
+++ b/main/core/src/util/JsonFormatters.scala
diff --git a/main/core/src/mill/util/Loggers.scala b/main/core/src/util/Loggers.scala
index aab1a324..aab1a324 100644
--- a/main/core/src/mill/util/Loggers.scala
+++ b/main/core/src/util/Loggers.scala
diff --git a/main/core/src/mill/util/MultiBiMap.scala b/main/core/src/util/MultiBiMap.scala
index 73bb42c4..51ea63f2 100644
--- a/main/core/src/mill/util/MultiBiMap.scala
+++ b/main/core/src/util/MultiBiMap.scala
@@ -1,7 +1,7 @@
 package mill.util
 
 import scala.collection.mutable
-import Strict.Agg
+import mill.api.Strict.Agg
 
 /**
   * A map from keys to collections of values: you can assign multiple values
diff --git a/main/core/src/mill/util/ParseArgs.scala b/main/core/src/util/ParseArgs.scala
index fc1a8ab3..fc1a8ab3 100644
--- a/main/core/src/mill/util/ParseArgs.scala
+++ b/main/core/src/util/ParseArgs.scala
diff --git a/main/core/src/mill/util/Router.scala b/main/core/src/util/Router.scala
index 5dd3c947..5dd3c947 100644
--- a/main/core/src/mill/util/Router.scala
+++ b/main/core/src/util/Router.scala
diff --git a/main/core/src/mill/util/Scripts.scala b/main/core/src/util/Scripts.scala
index 65eb6b2b..65eb6b2b 100644
--- a/main/core/src/mill/util/Scripts.scala
+++ b/main/core/src/util/Scripts.scala
diff --git a/main/core/src/mill/util/Watched.scala b/main/core/src/util/Watched.scala
index 29be53c3..29be53c3 100644
--- a/main/core/src/mill/util/Watched.scala
+++ b/main/core/src/util/Watched.scala
diff --git a/main/core/src/mill/util/package.scala b/main/core/src/util/package.scala
index ec5d2efc..ec5d2efc 100644
--- a/main/core/src/mill/util/package.scala
+++ b/main/core/src/util/package.scala
diff --git a/main/graphviz/src/mill/main/graphviz/GraphvizTools.scala b/main/graphviz/src/GraphvizTools.scala
index 9812c81f..9812c81f 100644
--- a/main/graphviz/src/mill/main/graphviz/GraphvizTools.scala
+++ b/main/graphviz/src/GraphvizTools.scala
diff --git a/main/moduledefs/src/mill/moduledefs/AutoOverridePlugin.scala b/main/moduledefs/src/AutoOverridePlugin.scala
index a870e7ec..a870e7ec 100644
--- a/main/moduledefs/src/mill/moduledefs/AutoOverridePlugin.scala
+++ b/main/moduledefs/src/AutoOverridePlugin.scala
diff --git a/main/moduledefs/src/mill/moduledefs/Cacher.scala b/main/moduledefs/src/Cacher.scala
index 023f03be..023f03be 100644
--- a/main/moduledefs/src/mill/moduledefs/Cacher.scala
+++ b/main/moduledefs/src/Cacher.scala
diff --git a/main/moduledefs/src/mill/moduledefs/Scaladoc.java b/main/moduledefs/src/Scaladoc.java
index 7a7d700b..7a7d700b 100644
--- a/main/moduledefs/src/mill/moduledefs/Scaladoc.java
+++ b/main/moduledefs/src/Scaladoc.java
diff --git a/main/src/mill/MillMain.scala b/main/src/MillMain.scala
index e953e65d..e953e65d 100644
--- a/main/src/mill/MillMain.scala
+++ b/main/src/MillMain.scala
diff --git a/main/src/mill/main/MainModule.scala b/main/src/main/MainModule.scala
index 34145668..dbe92cc2 100644
--- a/main/src/mill/main/MainModule.scala
+++ b/main/src/main/MainModule.scala
@@ -32,6 +32,10 @@ trait MainModule extends mill.Module{
   implicit def millDiscover: mill.define.Discover[_]
   implicit def millScoptTasksReads[T] = new mill.main.Tasks.Scopt[T]()
   implicit def millScoptEvaluatorReads[T] = new mill.main.EvaluatorScopt[T]()
+
+  /**
+    * Show the mill version.
+    */
   def version() = mill.T.command {
     val res = System.getProperty("MILL_VERSION")
     println(res)
diff --git a/main/src/mill/main/MainRunner.scala b/main/src/main/MainRunner.scala
index e50ed370..e50ed370 100644
--- a/main/src/mill/main/MainRunner.scala
+++ b/main/src/main/MainRunner.scala
diff --git a/main/src/mill/main/MainScopts.scala b/main/src/main/MainScopts.scala
index 718a30e6..718a30e6 100644
--- a/main/src/mill/main/MainScopts.scala
+++ b/main/src/main/MainScopts.scala
diff --git a/main/src/mill/main/MillServerMain.scala b/main/src/main/MillServerMain.scala
index 26ca99e6..26ca99e6 100644
--- a/main/src/mill/main/MillServerMain.scala
+++ b/main/src/main/MillServerMain.scala
diff --git a/main/src/mill/main/ReplApplyHandler.scala b/main/src/main/ReplApplyHandler.scala
index a8e467d4..786a1409 100644
--- a/main/src/mill/main/ReplApplyHandler.scala
+++ b/main/src/main/ReplApplyHandler.scala
@@ -6,7 +6,7 @@ import mill.define.Segment.Label
 import mill.define._
 import mill.eval.{Evaluator, Result}
 
-import mill.util.Strict.Agg
+import mill.api.Strict.Agg
 
 import scala.collection.mutable
 object ReplApplyHandler{
diff --git a/main/src/mill/main/Resolve.scala b/main/src/main/Resolve.scala
index a2c186ed..a2c186ed 100644
--- a/main/src/mill/main/Resolve.scala
+++ b/main/src/main/Resolve.scala
diff --git a/main/src/mill/main/RunScript.scala b/main/src/main/RunScript.scala
index 47526631..b858c8b9 100644
--- a/main/src/mill/main/RunScript.scala
+++ b/main/src/main/RunScript.scala
@@ -11,7 +11,7 @@ import mill.define._
 import mill.eval.{Evaluator, PathRef, Result}
 import mill.util.{EitherOps, ParseArgs, Watched}
 import mill.api.Logger
-import mill.util.Strict.Agg
+import mill.api.Strict.Agg
 
 import scala.collection.mutable
 import scala.reflect.ClassTag
diff --git a/main/src/mill/main/VisualizeModule.scala b/main/src/main/VisualizeModule.scala
index e950973f..e950973f 100644
--- a/main/src/mill/main/VisualizeModule.scala
+++ b/main/src/main/VisualizeModule.scala
diff --git a/main/src/mill/modules/Assembly.scala b/main/src/modules/Assembly.scala
index 141bc226..141bc226 100644
--- a/main/src/mill/modules/Assembly.scala
+++ b/main/src/modules/Assembly.scala
diff --git a/main/src/mill/modules/Jvm.scala b/main/src/modules/Jvm.scala
index 1a51ed8b..e17631e3 100644
--- a/main/src/mill/modules/Jvm.scala
+++ b/main/src/modules/Jvm.scala
@@ -15,7 +15,7 @@ import mill.main.client.InputPumper
 import mill.eval.{PathRef, Result}
 import mill.util.Ctx
 import mill.api.IO
-import mill.util.Loose.Agg
+import mill.api.Loose.Agg
 
 import scala.collection.mutable
 import scala.collection.JavaConverters._
diff --git a/main/src/mill/modules/Util.scala b/main/src/modules/Util.scala
index 2b98a304..029626fe 100644
--- a/main/src/mill/modules/Util.scala
+++ b/main/src/modules/Util.scala
@@ -3,7 +3,8 @@ package mill.modules
 
 import coursier.Repository
 import mill.api.{PathRef, IO}
-import mill.util.{Ctx, Loose}
+import mill.util.Ctx
+import mill.api.Loose
 
 
 object Util {
@@ -55,7 +56,7 @@ object Util {
     val localPath = sys.props(key)
     if (localPath != null) {
       mill.api.Result.Success(
-        Loose.Agg.from(localPath.split(',').map(p => PathRef(os.Path(p), quick = true)))
+        mill.api.Loose.Agg.from(localPath.split(',').map(p => PathRef(os.Path(p), quick = true)))
       )
     } else {
       mill.modules.Jvm.resolveDependencies(
diff --git a/main/src/mill/package.scala b/main/src/package.scala
index 0ccd094f..6bcb1bdf 100644
--- a/main/src/mill/package.scala
+++ b/main/src/package.scala
@@ -7,6 +7,6 @@ package object mill extends JsonFormatters{
   type PathRef = mill.api.PathRef
   type Module = define.Module
   type Cross[T] = define.Cross[T]
-  type Agg[T] = util.Loose.Agg[T]
-  val Agg = util.Loose.Agg
+  type Agg[T] = mill.api.Loose.Agg[T]
+  val Agg = mill.api.Loose.Agg
 }
diff --git a/main/test/resources/examples/javac/build.sc b/main/test/resources/examples/javac/build.sc
index 2ed9f915..17366219 100644
--- a/main/test/resources/examples/javac/build.sc
+++ b/main/test/resources/examples/javac/build.sc
@@ -2,7 +2,7 @@ import mill.T
 import mill.eval.JavaCompileJarTests.compileAll
 import mill.api.PathRef
 import mill.modules.Jvm
-import mill.util.Loose
+import mill.api.Loose
 
 def sourceRootPath = millSourcePath / 'src
 def resourceRootPath = millSourcePath / 'resources
diff --git a/main/test/src/mill/TestMain.scala b/main/test/src/TestMain.scala
index 80e7e627..80e7e627 100644
--- a/main/test/src/mill/TestMain.scala
+++ b/main/test/src/TestMain.scala
diff --git a/main/test/src/mill/UTestFramework.scala b/main/test/src/UTestFramework.scala
index c234151b..c234151b 100644
--- a/main/test/src/mill/UTestFramework.scala
+++ b/main/test/src/UTestFramework.scala
diff --git a/main/test/src/mill/define/ApplicativeTests.scala b/main/test/src/define/ApplicativeTests.scala
index 9dd2132f..9dd2132f 100644
--- a/main/test/src/mill/define/ApplicativeTests.scala
+++ b/main/test/src/define/ApplicativeTests.scala
diff --git a/main/test/src/mill/define/BasePathTests.scala b/main/test/src/define/BasePathTests.scala
index b8a653c8..b8a653c8 100644
--- a/main/test/src/mill/define/BasePathTests.scala
+++ b/main/test/src/define/BasePathTests.scala
diff --git a/main/test/src/mill/define/CacherTests.scala b/main/test/src/define/CacherTests.scala
index 59ebf3f6..1524e5c1 100644
--- a/main/test/src/mill/define/CacherTests.scala
+++ b/main/test/src/define/CacherTests.scala
@@ -1,7 +1,7 @@
 package mill.define
 
 import mill.util.{DummyLogger, TestEvaluator, TestUtil}
-import mill.util.Strict.Agg
+import mill.api.Strict.Agg
 import mill.T
 import mill.api.Result.Success
 import utest._
diff --git a/main/test/src/mill/define/DiscoverTests.scala b/main/test/src/define/DiscoverTests.scala
index 248d6afe..248d6afe 100644
--- a/main/test/src/mill/define/DiscoverTests.scala
+++ b/main/test/src/define/DiscoverTests.scala
diff --git a/main/test/src/mill/define/GraphTests.scala b/main/test/src/define/GraphTests.scala
index 224ce59f..b36dbf95 100644
--- a/main/test/src/mill/define/GraphTests.scala
+++ b/main/test/src/define/GraphTests.scala
@@ -4,7 +4,7 @@ package mill.define
 import mill.eval.Evaluator
 import mill.util.{TestGraphs, TestUtil}
 import utest._
-import mill.util.Strict.Agg
+import mill.api.Strict.Agg
 object GraphTests extends TestSuite{
 
   val tests = Tests{
diff --git a/main/test/src/mill/define/MacroErrorTests.scala b/main/test/src/define/MacroErrorTests.scala
index c8b140fa..c8b140fa 100644
--- a/main/test/src/mill/define/MacroErrorTests.scala
+++ b/main/test/src/define/MacroErrorTests.scala
diff --git a/main/test/src/mill/eval/CrossTests.scala b/main/test/src/eval/CrossTests.scala
index f194924e..f194924e 100644
--- a/main/test/src/mill/eval/CrossTests.scala
+++ b/main/test/src/eval/CrossTests.scala
diff --git a/main/test/src/mill/eval/EvaluationTests.scala b/main/test/src/eval/EvaluationTests.scala
index 74f9088c..7f924db2 100644
--- a/main/test/src/mill/eval/EvaluationTests.scala
+++ b/main/test/src/eval/EvaluationTests.scala
@@ -5,7 +5,7 @@ import mill.util.TestUtil.{Test, test}
 import mill.define.{Discover, Graph, Target, Task}
 import mill.{Module, T}
 import mill.util.{DummyLogger, TestEvaluator, TestGraphs, TestUtil}
-import mill.util.Strict.Agg
+import mill.api.Strict.Agg
 import utest._
 import utest.framework.TestPath
 
diff --git a/main/test/src/mill/eval/FailureTests.scala b/main/test/src/eval/FailureTests.scala
index dcfbcb60..dcfbcb60 100644
--- a/main/test/src/mill/eval/FailureTests.scala
+++ b/main/test/src/eval/FailureTests.scala
diff --git a/main/test/src/mill/eval/JavaCompileJarTests.scala b/main/test/src/eval/JavaCompileJarTests.scala
index 426c6ea6..0f9002df 100644
--- a/main/test/src/mill/eval/JavaCompileJarTests.scala
+++ b/main/test/src/eval/JavaCompileJarTests.scala
@@ -4,12 +4,13 @@ import mill.define.{Discover, Input, Target, Task}
 import mill.modules.Jvm
 import mill.api.Ctx.Dest
 import mill.{Module, T}
-import mill.util.{DummyLogger, Loose, TestEvaluator, TestUtil}
-import mill.util.Strict.Agg
+import mill.util.{DummyLogger, TestEvaluator, TestUtil}
+import mill.api.Strict.Agg
+import mill.api.Loose
 import utest._
 import mill._
 object JavaCompileJarTests extends TestSuite{
-  def compileAll(sources: mill.util.Loose.Agg[PathRef])(implicit ctx: Dest) = {
+  def compileAll(sources: mill.api.Loose.Agg[PathRef])(implicit ctx: Dest) = {
     os.makeDir.all(ctx.dest)
 
     os.proc("javac", sources.map(_.path.toString()).toSeq, "-d", ctx.dest).call(ctx.dest)
diff --git a/main/test/src/mill/eval/ModuleTests.scala b/main/test/src/eval/ModuleTests.scala
index f28fc9b6..f28fc9b6 100644
--- a/main/test/src/mill/eval/ModuleTests.scala
+++ b/main/test/src/eval/ModuleTests.scala
diff --git a/main/test/src/mill/eval/TarjanTests.scala b/main/test/src/eval/TarjanTests.scala
index 2f9d0a4d..2f9d0a4d 100644
--- a/main/test/src/mill/eval/TarjanTests.scala
+++ b/main/test/src/eval/TarjanTests.scala
diff --git a/main/test/src/mill/eval/TaskTests.scala b/main/test/src/eval/TaskTests.scala
index 0bfd8efc..0bfd8efc 100644
--- a/main/test/src/mill/eval/TaskTests.scala
+++ b/main/test/src/eval/TaskTests.scala
diff --git a/main/test/src/mill/main/ClientServerTests.scala b/main/test/src/main/ClientServerTests.scala
index 05238a5f..05238a5f 100644
--- a/main/test/src/mill/main/ClientServerTests.scala
+++ b/main/test/src/main/ClientServerTests.scala
diff --git a/main/test/src/mill/main/ForeignBuildsTest.scala b/main/test/src/main/ForeignBuildsTest.scala
index cfc8d00c..cfc8d00c 100644
--- a/main/test/src/mill/main/ForeignBuildsTest.scala
+++ b/main/test/src/main/ForeignBuildsTest.scala
diff --git a/main/test/src/mill/main/ForeignConflictTest.scala b/main/test/src/main/ForeignConflictTest.scala
index a4352bb6..a4352bb6 100644
--- a/main/test/src/mill/main/ForeignConflictTest.scala
+++ b/main/test/src/main/ForeignConflictTest.scala
diff --git a/main/test/src/mill/main/JavaCompileJarTests.scala b/main/test/src/main/JavaCompileJarTests.scala
index 37c64b05..37c64b05 100644
--- a/main/test/src/mill/main/JavaCompileJarTests.scala
+++ b/main/test/src/main/JavaCompileJarTests.scala
diff --git a/main/test/src/mill/main/MainTests.scala b/main/test/src/main/MainTests.scala
index e836099c..e836099c 100644
--- a/main/test/src/mill/main/MainTests.scala
+++ b/main/test/src/main/MainTests.scala
diff --git a/main/test/src/mill/util/ParseArgsTest.scala b/main/test/src/util/ParseArgsTest.scala
index e31baf4f..e31baf4f 100644
--- a/main/test/src/mill/util/ParseArgsTest.scala
+++ b/main/test/src/util/ParseArgsTest.scala
diff --git a/main/test/src/mill/util/ScriptTestSuite.scala b/main/test/src/util/ScriptTestSuite.scala
index f448aaaf..f448aaaf 100644
--- a/main/test/src/mill/util/ScriptTestSuite.scala
+++ b/main/test/src/util/ScriptTestSuite.scala
diff --git a/main/test/src/mill/util/TestEvaluator.scala b/main/test/src/util/TestEvaluator.scala
index 9a235679..81c8fe12 100644
--- a/main/test/src/mill/util/TestEvaluator.scala
+++ b/main/test/src/util/TestEvaluator.scala
@@ -3,7 +3,7 @@ package mill.util
 import mill.define.{Input, Target, Task}
 import mill.api.Result.OuterStack
 import mill.eval.{Evaluator, Result}
-import mill.util.Strict.Agg
+import mill.api.Strict.Agg
 import utest.assert
 import utest.framework.TestPath
 
diff --git a/main/test/src/mill/util/TestGraphs.scala b/main/test/src/util/TestGraphs.scala
index d3b35ddc..d3b35ddc 100644
--- a/main/test/src/mill/util/TestGraphs.scala
+++ b/main/test/src/util/TestGraphs.scala
diff --git a/main/test/src/mill/util/TestUtil.scala b/main/test/src/util/TestUtil.scala
index baab2992..462b7f5c 100644
--- a/main/test/src/mill/util/TestUtil.scala
+++ b/main/test/src/util/TestUtil.scala
@@ -5,7 +5,7 @@ import mill.define._
 import mill.api.Result
 import mill.api.Result.OuterStack
 import utest.assert
-import mill.util.Strict.Agg
+import mill.api.Strict.Agg
 import utest.framework.TestPath
 
 import scala.collection.mutable
diff --git a/scalajslib/api/src/mill/scalajslib/api/ScalaJSWorkerApi.scala b/scalajslib/api/src/ScalaJSWorkerApi.scala
index 4e44a8df..4e44a8df 100644
--- a/scalajslib/api/src/mill/scalajslib/api/ScalaJSWorkerApi.scala
+++ b/scalajslib/api/src/ScalaJSWorkerApi.scala
diff --git a/scalajslib/src/mill/scalajslib/ScalaJSModule.scala b/scalajslib/src/ScalaJSModule.scala
index 8568c39b..137e8ee2 100644
--- a/scalajslib/src/mill/scalajslib/ScalaJSModule.scala
+++ b/scalajslib/src/ScalaJSModule.scala
@@ -7,7 +7,8 @@ import mill.eval.{PathRef, Result}
 import mill.api.Result.Success
 import mill.scalalib.Lib.resolveDependencies
 import mill.scalalib.{DepSyntax, Lib, TestModule, TestRunner}
-import mill.util.{Ctx, Loose}
+import mill.util.Ctx
+import mill.api.Loose
 import mill.scalajslib.api._
 trait ScalaJSModule extends scalalib.ScalaModule { outer =>
 
diff --git a/scalajslib/src/mill/scalajslib/ScalaJSWorkerApi.scala b/scalajslib/src/ScalaJSWorkerApi.scala
index bcaeb2d3..bcaeb2d3 100644
--- a/scalajslib/src/mill/scalajslib/ScalaJSWorkerApi.scala
+++ b/scalajslib/src/ScalaJSWorkerApi.scala
diff --git a/scalajslib/test/resources/multi-module/shared/src/shared/Utils.scala b/scalajslib/test/resources/multi-module/shared/src/Utils.scala
index fad61a31..fad61a31 100644
--- a/scalajslib/test/resources/multi-module/shared/src/shared/Utils.scala
+++ b/scalajslib/test/resources/multi-module/shared/src/Utils.scala
diff --git a/scalajslib/test/src/mill/scalajslib/HelloJSWorldTests.scala b/scalajslib/test/src/HelloJSWorldTests.scala
index 1b3e9bb3..1b3e9bb3 100644
--- a/scalajslib/test/src/mill/scalajslib/HelloJSWorldTests.scala
+++ b/scalajslib/test/src/HelloJSWorldTests.scala
diff --git a/scalajslib/test/src/mill/scalajslib/MultiModuleTests.scala b/scalajslib/test/src/MultiModuleTests.scala
index 2ffea2cf..2ffea2cf 100644
--- a/scalajslib/test/src/mill/scalajslib/MultiModuleTests.scala
+++ b/scalajslib/test/src/MultiModuleTests.scala
diff --git a/scalajslib/test/src/mill/scalajslib/NodeJSConfigTests.scala b/scalajslib/test/src/NodeJSConfigTests.scala
index d9e6b45b..d9e6b45b 100644
--- a/scalajslib/test/src/mill/scalajslib/NodeJSConfigTests.scala
+++ b/scalajslib/test/src/NodeJSConfigTests.scala
diff --git a/scalajslib/test/src/mill/scalajslib/ScalaJsUtils.scala b/scalajslib/test/src/ScalaJsUtils.scala
index 68f2f7ee..68f2f7ee 100644
--- a/scalajslib/test/src/mill/scalajslib/ScalaJsUtils.scala
+++ b/scalajslib/test/src/ScalaJsUtils.scala
diff --git a/scalajslib/worker/0.6/src/mill/scalajslib/worker/ScalaJSWorkerImpl.scala b/scalajslib/worker/0.6/src/ScalaJSWorkerImpl.scala
index 64b668e5..64b668e5 100644
--- a/scalajslib/worker/0.6/src/mill/scalajslib/worker/ScalaJSWorkerImpl.scala
+++ b/scalajslib/worker/0.6/src/ScalaJSWorkerImpl.scala
diff --git a/scalajslib/worker/1.0/src/mill/scalajslib/worker/ScalaJSWorkerImpl.scala b/scalajslib/worker/1.0/src/ScalaJSWorkerImpl.scala
index f40f7a6b..f40f7a6b 100644
--- a/scalajslib/worker/1.0/src/mill/scalajslib/worker/ScalaJSWorkerImpl.scala
+++ b/scalajslib/worker/1.0/src/ScalaJSWorkerImpl.scala
diff --git a/scalalib/api/src/mill/scalalib/api/ZincWorkerApi.scala b/scalalib/api/src/ZincWorkerApi.scala
index c5230ec5..d42be9f3 100644
--- a/scalalib/api/src/mill/scalalib/api/ZincWorkerApi.scala
+++ b/scalalib/api/src/ZincWorkerApi.scala
@@ -3,14 +3,16 @@ package mill.scalalib.api
 import mill.api.Loose.Agg
 import mill.api.PathRef
 import mill.api.JsonFormatters._
-
+object ZincWorkerApi{
+  type Ctx = mill.api.Ctx.Dest with mill.api.Ctx.Log with mill.api.Ctx.Home
+}
 trait ZincWorkerApi {
   /** Compile a Java-only project */
   def compileJava(upstreamCompileOutput: Seq[CompilationResult],
                   sources: Agg[os.Path],
                   compileClasspath: Agg[os.Path],
                   javacOptions: Seq[String])
-                 (implicit ctx: mill.api.Ctx): mill.api.Result[CompilationResult]
+                 (implicit ctx: ZincWorkerApi.Ctx): mill.api.Result[CompilationResult]
 
   /** Compile a mixed Scala/Java or Scala-only project */
   def compileMixed(upstreamCompileOutput: Seq[CompilationResult],
@@ -18,21 +20,21 @@ trait ZincWorkerApi {
                    compileClasspath: Agg[os.Path],
                    javacOptions: Seq[String],
                    scalaVersion: String,
+                   scalaOrganization: String,
                    scalacOptions: Seq[String],
-                   compilerBridgeSources: os.Path,
                    compilerClasspath: Agg[os.Path],
                    scalacPluginClasspath: Agg[os.Path])
-                  (implicit ctx: mill.api.Ctx): mill.api.Result[CompilationResult]
+                  (implicit ctx: ZincWorkerApi.Ctx): mill.api.Result[CompilationResult]
 
   def discoverMainClasses(compilationResult: CompilationResult)
-                         (implicit ctx: mill.api.Ctx): Seq[String]
+                         (implicit ctx: ZincWorkerApi.Ctx): Seq[String]
 
   def docJar(scalaVersion: String,
-             compilerBridgeSources: os.Path,
+             scalaOrganization: String,
              compilerClasspath: Agg[os.Path],
              scalacPluginClasspath: Agg[os.Path],
              args: Seq[String])
-            (implicit ctx: mill.api.Ctx): Boolean
+            (implicit ctx: ZincWorkerApi.Ctx): Boolean
 }
 
 
diff --git a/scalalib/backgroundwrapper/src/mill/scalalib/backgroundwrapper/BackgroundWrapper.java b/scalalib/backgroundwrapper/src/BackgroundWrapper.java
index 02ee23eb..02ee23eb 100644
--- a/scalalib/backgroundwrapper/src/mill/scalalib/backgroundwrapper/BackgroundWrapper.java
+++ b/scalalib/backgroundwrapper/src/BackgroundWrapper.java
diff --git a/scalalib/src/mill/scalalib/Dep.scala b/scalalib/src/Dep.scala
index 714fa21e..714fa21e 100644
--- a/scalalib/src/mill/scalalib/Dep.scala
+++ b/scalalib/src/Dep.scala
diff --git a/scalalib/src/mill/scalalib/Dependency.scala b/scalalib/src/Dependency.scala
index 0c589663..0c589663 100644
--- a/scalalib/src/mill/scalalib/Dependency.scala
+++ b/scalalib/src/Dependency.scala
diff --git a/scalalib/src/mill/scalalib/GenIdeaImpl.scala b/scalalib/src/GenIdeaImpl.scala
index 2d76d804..b8f9d35e 100644
--- a/scalalib/src/mill/scalalib/GenIdeaImpl.scala
+++ b/scalalib/src/GenIdeaImpl.scala
@@ -5,8 +5,8 @@ import coursier.{Cache, CoursierPaths, Repository}
 import mill.define._
 import mill.eval.{Evaluator, PathRef, Result}
 import mill.api.Ctx.{Home, Log}
-import mill.util.Strict.Agg
-import mill.util.{Loose, Strict}
+import mill.api.Strict.Agg
+import mill.api.{Loose, Strict}
 import mill.{T, scalalib}
 
 import scala.util.Try
@@ -43,7 +43,7 @@ object GenIdeaImpl {
     val evaluator = new Evaluator(ctx.home, os.pwd / 'out, os.pwd / 'out, rootModule, ctx.log)
 
     for((relPath, xml) <- xmlFileLayout(evaluator, rootModule, jdkInfo)){
-      os.write.over(os.pwd/relPath, pp.format(xml))
+      os.write.over(os.pwd/relPath, pp.format(xml), createFolders = true)
     }
   }
 
diff --git a/scalalib/src/mill/scalalib/JavaModule.scala b/scalalib/src/JavaModule.scala
index 78be8893..72c0a5a6 100644
--- a/scalalib/src/mill/scalalib/JavaModule.scala
+++ b/scalalib/src/JavaModule.scala
@@ -9,7 +9,7 @@ import mill.modules.{Assembly, Jvm}
 import mill.modules.Jvm.{createAssembly, createJar}
 import Lib._
 import mill.scalalib.publish.{Artifact, Scope}
-import mill.util.Loose.Agg
+import mill.api.Loose.Agg
 
 /**
   * Core configuration required to compile a single Scala compilation target
diff --git a/scalalib/src/mill/scalalib/Lib.scala b/scalalib/src/Lib.scala
index b8b253bd..b8b253bd 100644
--- a/scalalib/src/mill/scalalib/Lib.scala
+++ b/scalalib/src/Lib.scala
diff --git a/scalalib/src/mill/scalalib/MiscModule.scala b/scalalib/src/MiscModule.scala
index c6449d6e..bf64f1f3 100644
--- a/scalalib/src/mill/scalalib/MiscModule.scala
+++ b/scalalib/src/MiscModule.scala
@@ -4,7 +4,7 @@ package scalalib
 import mill.define.Cross.Resolver
 import mill.define.{Cross, Task}
 import mill.eval.{PathRef, Result}
-import mill.util.Loose.Agg
+import mill.api.Loose.Agg
 object CrossModuleBase{
   def scalaVersionPaths(scalaVersion: String, f: String => os.Path) = {
     for(segments <- scalaVersion.split('.').inits.filter(_.nonEmpty))
diff --git a/scalalib/src/mill/scalalib/PublishModule.scala b/scalalib/src/PublishModule.scala
index 588781f4..588781f4 100644
--- a/scalalib/src/mill/scalalib/PublishModule.scala
+++ b/scalalib/src/PublishModule.scala
diff --git a/scalalib/src/mill/scalalib/ScalaModule.scala b/scalalib/src/ScalaModule.scala
index 9d669bf4..5fad1664 100644
--- a/scalalib/src/mill/scalalib/ScalaModule.scala
+++ b/scalalib/src/ScalaModule.scala
@@ -8,7 +8,7 @@ import mill.modules.Jvm
 import mill.modules.Jvm.createJar
 import mill.scalalib.api.Util.isDotty
 import Lib._
-import mill.util.Loose.Agg
+import mill.api.Loose.Agg
 import mill.api.DummyInputStream
 
 /**
@@ -79,36 +79,7 @@ trait ScalaModule extends JavaModule { outer =>
 
   def scalaDocOptions = T{ scalacOptions() }
 
-  private val Milestone213 = raw"""2.13.(\d+)-M(\d+)""".r
 
-  def scalaCompilerBridgeSources = T {
-    val (scalaVersion0, scalaBinaryVersion0) = scalaVersion() match {
-      case Milestone213(_, _) => ("2.13.0-M2", "2.13.0-M2")
-      case _ => (scalaVersion(), mill.scalalib.api.Util.scalaBinaryVersion(scalaVersion()))
-    }
-
-    val (bridgeDep, bridgeName, bridgeVersion) =
-      if (isDotty(scalaVersion0)) {
-        val org = scalaOrganization()
-        val name = "dotty-sbt-bridge"
-        val version = scalaVersion()
-        (ivy"$org:$name:$version", name, version)
-      } else {
-        val org = "org.scala-sbt"
-        val name = "compiler-bridge"
-        val version = Versions.zinc
-        (ivy"$org::$name:$version", s"${name}_$scalaBinaryVersion0", version)
-      }
-
-    resolveDependencies(
-      repositories,
-      Lib.depToDependency(_, scalaVersion0, platformSuffix()),
-      Seq(bridgeDep),
-      sources = true
-    ).map(deps =>
-      mill.scalalib.api.Util.grepJar(deps.map(_.path), bridgeName, bridgeVersion, sources = true)
-    )
-  }
 
   /**
     * The local classpath of Scala compiler plugins on-disk; you can add
@@ -159,8 +130,8 @@ trait ScalaModule extends JavaModule { outer =>
       compileClasspath().map(_.path),
       javacOptions(),
       scalaVersion(),
+      scalaOrganization(),
       scalacOptions(),
-      scalaCompilerBridgeSources(),
       scalaCompilerClasspath().map(_.path),
       scalacPluginClasspath().map(_.path),
     )
@@ -187,7 +158,7 @@ trait ScalaModule extends JavaModule { outer =>
     else {
       zincWorker.worker().docJar(
         scalaVersion(),
-        scalaCompilerBridgeSources(),
+        scalaOrganization(),
         scalaCompilerClasspath().map(_.path),
         scalacPluginClasspath().map(_.path),
         files ++ options
diff --git a/scalalib/src/mill/scalalib/TestRunner.scala b/scalalib/src/TestRunner.scala
index 42e65d63..42e65d63 100644
--- a/scalalib/src/mill/scalalib/TestRunner.scala
+++ b/scalalib/src/TestRunner.scala
diff --git a/scalalib/src/mill/scalalib/Versions.scala b/scalalib/src/Versions.scala
index e3697abb..e3697abb 100644
--- a/scalalib/src/mill/scalalib/Versions.scala
+++ b/scalalib/src/Versions.scala
diff --git a/scalalib/src/ZincWorkerModule.scala b/scalalib/src/ZincWorkerModule.scala
new file mode 100644
index 00000000..97d84aaf
--- /dev/null
+++ b/scalalib/src/ZincWorkerModule.scala
@@ -0,0 +1,109 @@
+package mill.scalalib
+
+import coursier.Cache
+import coursier.maven.MavenRepository
+import mill.Agg
+import mill.T
+import mill.api.KeyedLockedCache
+import mill.define.{Discover, Worker}
+import mill.scalalib.Lib.resolveDependencies
+import mill.scalalib.api.Util.isDotty
+import mill.scalalib.api.ZincWorkerApi
+import mill.api.Loose
+import mill.util.JsonFormatters._
+
+object ZincWorkerModule extends mill.define.ExternalModule with ZincWorkerModule{
+  lazy val millDiscover = Discover[this.type]
+}
+trait ZincWorkerModule extends mill.Module{
+  def repositories = Seq(
+    Cache.ivy2Local,
+    MavenRepository("https://repo1.maven.org/maven2"),
+    MavenRepository("https://oss.sonatype.org/content/repositories/releases")
+  )
+
+  def classpath = T{
+    mill.modules.Util.millProjectModule("MILL_SCALA_WORKER", "mill-scalalib-worker", repositories)
+  }
+
+  def scalalibClasspath = T{
+    mill.modules.Util.millProjectModule("MILL_SCALA_LIB", "mill-scalalib", repositories)
+  }
+
+  def backgroundWrapperClasspath = T{
+    mill.modules.Util.millProjectModule(
+      "MILL_BACKGROUNDWRAPPER", "mill-scalalib-backgroundwrapper",
+      repositories, artifactSuffix = ""
+    )
+  }
+
+  def worker: Worker[mill.scalalib.api.ZincWorkerApi] = T.worker{
+    val cl = mill.api.ClassLoader.create(
+      classpath().map(_.path.toNIO.toUri.toURL).toVector,
+      getClass.getClassLoader
+    )
+    val cls = cl.loadClass("mill.scalalib.worker.ZincWorkerImpl")
+    val instance = cls.getConstructor(
+      classOf[
+        Either[
+          (ZincWorkerApi.Ctx, Array[os.Path], (String, String) => os.Path),
+          String => os.Path
+        ]
+      ],
+      classOf[(Agg[os.Path], String) => os.Path],
+      classOf[(Agg[os.Path], String) => os.Path],
+      classOf[KeyedLockedCache[_]]
+    )
+      .newInstance(
+        Left((
+          T.ctx(),
+          compilerInterfaceClasspath().map(_.path).toArray,
+          (x: String, y: String) => scalaCompilerBridgeSourceJar(x, y).asSuccess.get.value
+        )),
+        mill.scalalib.api.Util.grepJar(_, "scala-library", _, sources = false),
+        mill.scalalib.api.Util.grepJar(_, "scala-compiler", _, sources = false),
+        new KeyedLockedCache.RandomBoundedCache(1, 1)
+      )
+    instance.asInstanceOf[mill.scalalib.api.ZincWorkerApi]
+  }
+
+  private val Milestone213 = raw"""2.13.(\d+)-M(\d+)""".r
+  def scalaCompilerBridgeSourceJar(scalaVersion: String,
+                                   scalaOrganization: String) = {
+    val (scalaVersion0, scalaBinaryVersion0) = scalaVersion match {
+      case Milestone213(_, _) => ("2.13.0-M2", "2.13.0-M2")
+      case _ => (scalaVersion, mill.scalalib.api.Util.scalaBinaryVersion(scalaVersion))
+    }
+
+    val (bridgeDep, bridgeName, bridgeVersion) =
+      if (isDotty(scalaVersion0)) {
+        val org = scalaOrganization
+        val name = "dotty-sbt-bridge"
+        val version = scalaVersion
+        (ivy"$org:$name:$version", name, version)
+      } else {
+        val org = "org.scala-sbt"
+        val name = "compiler-bridge"
+        val version = Versions.zinc
+        (ivy"$org::$name:$version", s"${name}_$scalaBinaryVersion0", version)
+      }
+
+    resolveDependencies(
+      repositories,
+      Lib.depToDependency(_, scalaVersion0, ""),
+      Seq(bridgeDep),
+      sources = true
+    ).map(deps =>
+      mill.scalalib.api.Util.grepJar(deps.map(_.path), bridgeName, bridgeVersion, sources = true)
+    )
+  }
+
+  def compilerInterfaceClasspath = T{
+    resolveDependencies(
+      repositories,
+      Lib.depToDependency(_, "2.12.4", ""),
+      Seq(ivy"org.scala-sbt:compiler-interface:${Versions.zinc}")
+    )
+  }
+
+}
diff --git a/scalalib/src/mill/scalalib/dependency/DependencyUpdatesImpl.scala b/scalalib/src/dependency/DependencyUpdatesImpl.scala
index 3bb94202..3bb94202 100644
--- a/scalalib/src/mill/scalalib/dependency/DependencyUpdatesImpl.scala
+++ b/scalalib/src/dependency/DependencyUpdatesImpl.scala
diff --git a/scalalib/src/mill/scalalib/dependency/metadata/MavenMetadataLoader.scala b/scalalib/src/dependency/metadata/MavenMetadataLoader.scala
index 491911bf..491911bf 100644
--- a/scalalib/src/mill/scalalib/dependency/metadata/MavenMetadataLoader.scala
+++ b/scalalib/src/dependency/metadata/MavenMetadataLoader.scala
diff --git a/scalalib/src/mill/scalalib/dependency/metadata/MetadataLoader.scala b/scalalib/src/dependency/metadata/MetadataLoader.scala
index 20271f0e..20271f0e 100644
--- a/scalalib/src/mill/scalalib/dependency/metadata/MetadataLoader.scala
+++ b/scalalib/src/dependency/metadata/MetadataLoader.scala
diff --git a/scalalib/src/mill/scalalib/dependency/metadata/MetadataLoaderFactory.scala b/scalalib/src/dependency/metadata/MetadataLoaderFactory.scala
index 4495d6b0..4495d6b0 100644
--- a/scalalib/src/mill/scalalib/dependency/metadata/MetadataLoaderFactory.scala
+++ b/scalalib/src/dependency/metadata/MetadataLoaderFactory.scala
diff --git a/scalalib/src/mill/scalalib/dependency/updates/ModuleDependenciesUpdates.scala b/scalalib/src/dependency/updates/ModuleDependenciesUpdates.scala
index a989cd31..a989cd31 100644
--- a/scalalib/src/mill/scalalib/dependency/updates/ModuleDependenciesUpdates.scala
+++ b/scalalib/src/dependency/updates/ModuleDependenciesUpdates.scala
diff --git a/scalalib/src/mill/scalalib/dependency/updates/UpdatesFinder.scala b/scalalib/src/dependency/updates/UpdatesFinder.scala
index 3430592f..3430592f 100644
--- a/scalalib/src/mill/scalalib/dependency/updates/UpdatesFinder.scala
+++ b/scalalib/src/dependency/updates/UpdatesFinder.scala
diff --git a/scalalib/src/mill/scalalib/dependency/versions/ModuleDependenciesVersions.scala b/scalalib/src/dependency/versions/ModuleDependenciesVersions.scala
index 12d57059..12d57059 100644
--- a/scalalib/src/mill/scalalib/dependency/versions/ModuleDependenciesVersions.scala
+++ b/scalalib/src/dependency/versions/ModuleDependenciesVersions.scala
diff --git a/scalalib/src/mill/scalalib/dependency/versions/Version.scala b/scalalib/src/dependency/versions/Version.scala
index a2719023..a2719023 100644
--- a/scalalib/src/mill/scalalib/dependency/versions/Version.scala
+++ b/scalalib/src/dependency/versions/Version.scala
diff --git a/scalalib/src/mill/scalalib/dependency/versions/VersionParser.scala b/scalalib/src/dependency/versions/VersionParser.scala
index 10aebd73..10aebd73 100644
--- a/scalalib/src/mill/scalalib/dependency/versions/VersionParser.scala
+++ b/scalalib/src/dependency/versions/VersionParser.scala
diff --git a/scalalib/src/mill/scalalib/dependency/versions/VersionsFinder.scala b/scalalib/src/dependency/versions/VersionsFinder.scala
index a831ffc3..a9ecc763 100644
--- a/scalalib/src/mill/scalalib/dependency/versions/VersionsFinder.scala
+++ b/scalalib/src/dependency/versions/VersionsFinder.scala
@@ -5,7 +5,7 @@ import mill.eval.Evaluator
 import mill.scalalib.dependency.metadata.MetadataLoaderFactory
 import mill.scalalib.{Dep, JavaModule, Lib}
 import mill.api.Ctx.{Home, Log}
-import mill.util.{Loose, Strict}
+import mill.api.{Loose, Strict}
 
 private[dependency] object VersionsFinder {
 
diff --git a/scalalib/src/mill/scalalib/ZincWorkerModule.scala b/scalalib/src/mill/scalalib/ZincWorkerModule.scala
deleted file mode 100644
index 5ca824ce..00000000
--- a/scalalib/src/mill/scalalib/ZincWorkerModule.scala
+++ /dev/null
@@ -1,56 +0,0 @@
-package mill.scalalib
-
-import coursier.Cache
-import coursier.maven.MavenRepository
-import mill.Agg
-import mill.T
-import mill.define.{Discover, Worker}
-import mill.scalalib.Lib.resolveDependencies
-import mill.util.Loose
-import mill.util.JsonFormatters._
-
-object ZincWorkerModule extends mill.define.ExternalModule with ZincWorkerModule{
-  lazy val millDiscover = Discover[this.type]
-}
-trait ZincWorkerModule extends mill.Module{
-  def repositories = Seq(
-    Cache.ivy2Local,
-    MavenRepository("https://repo1.maven.org/maven2"),
-    MavenRepository("https://oss.sonatype.org/content/repositories/releases")
-  )
-
-  def classpath = T{
-    mill.modules.Util.millProjectModule("MILL_SCALA_WORKER", "mill-scalalib-worker", repositories)
-  }
-
-  def scalalibClasspath = T{
-    mill.modules.Util.millProjectModule("MILL_SCALA_LIB", "mill-scalalib", repositories)
-  }
-
-  def backgroundWrapperClasspath = T{
-    mill.modules.Util.millProjectModule(
-      "MILL_BACKGROUNDWRAPPER", "mill-scalalib-backgroundwrapper",
-      repositories, artifactSuffix = ""
-    )
-  }
-
-  def worker: Worker[mill.scalalib.api.ZincWorkerApi] = T.worker{
-    val cl = mill.api.ClassLoader.create(
-      classpath().map(_.path.toNIO.toUri.toURL).toVector,
-      getClass.getClassLoader
-    )
-    val cls = cl.loadClass("mill.scalalib.worker.ZincWorkerImpl")
-    val instance = cls.getConstructor(classOf[mill.api.Ctx], classOf[Array[String]])
-      .newInstance(T.ctx(), compilerInterfaceClasspath().map(_.path.toString).toArray[String])
-    instance.asInstanceOf[mill.scalalib.api.ZincWorkerApi]
-  }
-
-  def compilerInterfaceClasspath = T{
-    resolveDependencies(
-      repositories,
-      Lib.depToDependency(_, "2.12.4", ""),
-      Seq(ivy"org.scala-sbt:compiler-interface:${Versions.zinc}")
-    )
-  }
-
-}
diff --git a/scalalib/src/mill/scalalib/package.scala b/scalalib/src/package.scala
index 5a282e82..5a282e82 100644
--- a/scalalib/src/mill/scalalib/package.scala
+++ b/scalalib/src/package.scala
diff --git a/scalalib/src/mill/scalalib/publish/Ivy.scala b/scalalib/src/publish/Ivy.scala
index 22e26ff6..e06efadd 100644
--- a/scalalib/src/mill/scalalib/publish/Ivy.scala
+++ b/scalalib/src/publish/Ivy.scala
@@ -1,6 +1,6 @@
 package mill.scalalib.publish
 
-import mill.util.Loose.Agg
+import mill.api.Loose.Agg
 
 import scala.xml.PrettyPrinter
 
diff --git a/scalalib/src/mill/scalalib/publish/JsonFormatters.scala b/scalalib/src/publish/JsonFormatters.scala
index 8fc90632..8fc90632 100644
--- a/scalalib/src/mill/scalalib/publish/JsonFormatters.scala
+++ b/scalalib/src/publish/JsonFormatters.scala
diff --git a/scalalib/src/mill/scalalib/publish/Licence.scala b/scalalib/src/publish/Licence.scala
index 8838ef69..8838ef69 100644
--- a/scalalib/src/mill/scalalib/publish/Licence.scala
+++ b/scalalib/src/publish/Licence.scala
diff --git a/scalalib/src/mill/scalalib/publish/LocalPublisher.scala b/scalalib/src/publish/LocalPublisher.scala
index d9839831..d9839831 100644
--- a/scalalib/src/mill/scalalib/publish/LocalPublisher.scala
+++ b/scalalib/src/publish/LocalPublisher.scala
diff --git a/scalalib/src/mill/scalalib/publish/Pom.scala b/scalalib/src/publish/Pom.scala
index 57a0e196..a7f1f6fc 100644
--- a/scalalib/src/mill/scalalib/publish/Pom.scala
+++ b/scalalib/src/publish/Pom.scala
@@ -1,6 +1,6 @@
 package mill.scalalib.publish
 
-import mill.util.Loose.Agg
+import mill.api.Loose.Agg
 
 import scala.xml.{Atom, Elem, NodeSeq, PrettyPrinter}
 
diff --git a/scalalib/src/mill/scalalib/publish/SonatypeHttpApi.scala b/scalalib/src/publish/SonatypeHttpApi.scala
index 12defa93..12defa93 100644
--- a/scalalib/src/mill/scalalib/publish/SonatypeHttpApi.scala
+++ b/scalalib/src/publish/SonatypeHttpApi.scala
diff --git a/scalalib/src/mill/scalalib/publish/SonatypePublisher.scala b/scalalib/src/publish/SonatypePublisher.scala
index 1843943b..1843943b 100644
--- a/scalalib/src/mill/scalalib/publish/SonatypePublisher.scala
+++ b/scalalib/src/publish/SonatypePublisher.scala
diff --git a/scalalib/src/mill/scalalib/publish/VersionControl.scala b/scalalib/src/publish/VersionControl.scala
index aad38ac3..aad38ac3 100644
--- a/scalalib/src/mill/scalalib/publish/VersionControl.scala
+++ b/scalalib/src/publish/VersionControl.scala
diff --git a/scalalib/src/mill/scalalib/publish/package.scala b/scalalib/src/publish/package.scala
index 99eeec14..99eeec14 100644
--- a/scalalib/src/mill/scalalib/publish/package.scala
+++ b/scalalib/src/publish/package.scala
diff --git a/scalalib/src/mill/scalalib/publish/settings.scala b/scalalib/src/publish/settings.scala
index bca81cf0..bca81cf0 100644
--- a/scalalib/src/mill/scalalib/publish/settings.scala
+++ b/scalalib/src/publish/settings.scala
diff --git a/scalalib/src/mill/scalalib/scalafmt/ScalafmtModule.scala b/scalalib/src/scalafmt/ScalafmtModule.scala
index 6a81d975..6a81d975 100644
--- a/scalalib/src/mill/scalalib/scalafmt/ScalafmtModule.scala
+++ b/scalalib/src/scalafmt/ScalafmtModule.scala
diff --git a/scalalib/src/mill/scalalib/scalafmt/ScalafmtWorker.scala b/scalalib/src/scalafmt/ScalafmtWorker.scala
index 47d8375f..47d8375f 100644
--- a/scalalib/src/mill/scalalib/scalafmt/ScalafmtWorker.scala
+++ b/scalalib/src/scalafmt/ScalafmtWorker.scala
diff --git a/scalalib/test/resources/hello-java/app/src/hello/Main.java b/scalalib/test/resources/hello-java/app/src/Main.java
index 23ddd679..23ddd679 100644
--- a/scalalib/test/resources/hello-java/app/src/hello/Main.java
+++ b/scalalib/test/resources/hello-java/app/src/Main.java
diff --git a/scalalib/test/resources/hello-java/app/test/src/hello/MyAppTests.java b/scalalib/test/resources/hello-java/app/test/src/MyAppTests.java
index df0d0351..df0d0351 100644
--- a/scalalib/test/resources/hello-java/app/test/src/hello/MyAppTests.java
+++ b/scalalib/test/resources/hello-java/app/test/src/MyAppTests.java
diff --git a/scalalib/test/resources/hello-java/core/src/hello/Core.java b/scalalib/test/resources/hello-java/core/src/Core.java
index 3ecb1f61..3ecb1f61 100644
--- a/scalalib/test/resources/hello-java/core/src/hello/Core.java
+++ b/scalalib/test/resources/hello-java/core/src/Core.java
diff --git a/scalalib/test/resources/hello-java/core/test/src/hello/MyCoreTests.java b/scalalib/test/resources/hello-java/core/test/src/MyCoreTests.java
index 38bebaeb..38bebaeb 100644
--- a/scalalib/test/resources/hello-java/core/test/src/hello/MyCoreTests.java
+++ b/scalalib/test/resources/hello-java/core/test/src/MyCoreTests.java
diff --git a/scalalib/test/src/mill/scalalib/GenIdeaTests.scala b/scalalib/test/src/GenIdeaTests.scala
index 50db95c0..50db95c0 100644
--- a/scalalib/test/src/mill/scalalib/GenIdeaTests.scala
+++ b/scalalib/test/src/GenIdeaTests.scala
diff --git a/scalalib/test/src/mill/scalalib/HelloJavaTests.scala b/scalalib/test/src/HelloJavaTests.scala
index 5b7b93b2..02c2567f 100644
--- a/scalalib/test/src/mill/scalalib/HelloJavaTests.scala
+++ b/scalalib/test/src/HelloJavaTests.scala
@@ -88,8 +88,8 @@ object HelloJavaTests extends TestSuite {
     'failures - {
       val eval = init()
 
-      val mainJava = HelloJava.millSourcePath / 'app / 'src / 'hello / "Main.java"
-      val coreJava = HelloJava.millSourcePath / 'core / 'src / 'hello / "Core.java"
+      val mainJava = HelloJava.millSourcePath / 'app / 'src / "Main.java"
+      val coreJava = HelloJava.millSourcePath / 'core / 'src / "Core.java"
 
       val Right(_) = eval.apply(HelloJava.core.compile)
       val Right(_) = eval.apply(HelloJava.app.compile)
diff --git a/scalalib/test/src/mill/scalalib/HelloWorldTests.scala b/scalalib/test/src/HelloWorldTests.scala
index da08f056..da08f056 100644
--- a/scalalib/test/src/mill/scalalib/HelloWorldTests.scala
+++ b/scalalib/test/src/HelloWorldTests.scala
diff --git a/scalalib/test/src/mill/scalalib/ResolveDepsTests.scala b/scalalib/test/src/ResolveDepsTests.scala
index 78361625..ce905907 100644
--- a/scalalib/test/src/mill/scalalib/ResolveDepsTests.scala
+++ b/scalalib/test/src/ResolveDepsTests.scala
@@ -4,7 +4,7 @@ import coursier.Cache
 import coursier.maven.MavenRepository
 import mill.api.Result.{Failure, Success}
 import mill.eval.{PathRef, Result}
-import mill.util.Loose.Agg
+import mill.api.Loose.Agg
 import utest._
 
 object ResolveDepsTests extends TestSuite {
diff --git a/scalalib/test/src/mill/scalalib/VersionControlTests.scala b/scalalib/test/src/VersionControlTests.scala
index fafdca2d..fafdca2d 100644
--- a/scalalib/test/src/mill/scalalib/VersionControlTests.scala
+++ b/scalalib/test/src/VersionControlTests.scala
diff --git a/scalalib/test/src/mill/scalalib/dependency/metadata/MetadataLoaderFactoryTests.scala b/scalalib/test/src/dependency/metadata/MetadataLoaderFactoryTests.scala
index 4c2206b8..4c2206b8 100644
--- a/scalalib/test/src/mill/scalalib/dependency/metadata/MetadataLoaderFactoryTests.scala
+++ b/scalalib/test/src/dependency/metadata/MetadataLoaderFactoryTests.scala
diff --git a/scalalib/test/src/mill/scalalib/dependency/updates/UpdatesFinderTests.scala b/scalalib/test/src/dependency/updates/UpdatesFinderTests.scala
index 7b6e6e36..7b6e6e36 100644
--- a/scalalib/test/src/mill/scalalib/dependency/updates/UpdatesFinderTests.scala
+++ b/scalalib/test/src/dependency/updates/UpdatesFinderTests.scala
diff --git a/scalalib/test/src/mill/scalalib/dependency/versions/VersionTests.scala b/scalalib/test/src/dependency/versions/VersionTests.scala
index b916c86f..b916c86f 100644
--- a/scalalib/test/src/mill/scalalib/dependency/versions/VersionTests.scala
+++ b/scalalib/test/src/dependency/versions/VersionTests.scala
diff --git a/scalalib/test/src/mill/scalalib/publish/IvyTests.scala b/scalalib/test/src/publish/IvyTests.scala
index d187f969..d187f969 100644
--- a/scalalib/test/src/mill/scalalib/publish/IvyTests.scala
+++ b/scalalib/test/src/publish/IvyTests.scala
diff --git a/scalalib/test/src/mill/scalalib/publish/PomTests.scala b/scalalib/test/src/publish/PomTests.scala
index 307ae379..307ae379 100644
--- a/scalalib/test/src/mill/scalalib/publish/PomTests.scala
+++ b/scalalib/test/src/publish/PomTests.scala
diff --git a/scalalib/test/src/mill/scalalib/scalafmt/ScalafmtTests.scala b/scalalib/test/src/scalafmt/ScalafmtTests.scala
index dcbdb769..dcbdb769 100644
--- a/scalalib/test/src/mill/scalalib/scalafmt/ScalafmtTests.scala
+++ b/scalalib/test/src/scalafmt/ScalafmtTests.scala
diff --git a/scalalib/worker/src/mill/scalalib/worker/ZincWorkerImpl.scala b/scalalib/worker/src/ZincWorkerImpl.scala
index 705d4682..c37ef162 100644
--- a/scalalib/worker/src/mill/scalalib/worker/ZincWorkerImpl.scala
+++ b/scalalib/worker/src/ZincWorkerImpl.scala
@@ -4,13 +4,13 @@ import java.io.File
 import java.util.Optional
 
 import mill.api.Loose.Agg
-import mill.api.PathRef
+import mill.api.{KeyedLockedCache, PathRef}
 import xsbti.compile.{CompilerCache => _, FileAnalysisStore => _, ScalaInstance => _, _}
-import mill.scalalib.api.Util.{isDotty, grepJar, scalaBinaryVersion}
+import mill.scalalib.api.Util.{grepJar, isDotty, scalaBinaryVersion}
 import sbt.internal.inc._
 import sbt.internal.util.{ConsoleOut, MainAppender}
 import sbt.util.LogExchange
-import mill.scalalib.api.CompilationResult
+import mill.scalalib.api.{CompilationResult, ZincWorkerApi}
 case class MockedLookup(am: File => Optional[CompileAnalysis]) extends PerClasspathEntryLookup {
   override def analysis(classpathEntry: File): Optional[CompileAnalysis] =
     am(classpathEntry)
@@ -19,10 +19,16 @@ case class MockedLookup(am: File => Optional[CompileAnalysis]) extends PerClassp
     Locate.definesClass(classpathEntry)
 }
 
-class ZincWorkerImpl(ctx0: mill.api.Ctx,
-                     compilerBridgeClasspath: Array[String]) extends mill.scalalib.api.ZincWorkerApi{
+class ZincWorkerImpl(compilerBridge: Either[
+                       (ZincWorkerApi.Ctx, Array[os.Path], (String, String) => os.Path),
+                       String => os.Path
+                     ],
+                     libraryJarNameGrep: (Agg[os.Path], String) => os.Path,
+                     compilerJarNameGrep: (Agg[os.Path], String) => os.Path,
+                     compilerCache: KeyedLockedCache[Compilers])
+    extends ZincWorkerApi{
   private val ic = new sbt.internal.inc.IncrementalCompilerImpl()
-  val javaOnlyCompilers = {
+  lazy val javaOnlyCompilers = {
     // Keep the classpath as written by the user
     val classpathOptions = ClasspathOptions.of(false, false, false, false, false)
 
@@ -42,68 +48,68 @@ class ZincWorkerImpl(ctx0: mill.api.Ctx,
     )
   }
 
-  @volatile var mixedCompilersCache = Option.empty[(Long, Compilers)]
-
   def docJar(scalaVersion: String,
-             compilerBridgeSources: os.Path,
+             scalaOrganization: String,
              compilerClasspath: Agg[os.Path],
              scalacPluginClasspath: Agg[os.Path],
              args: Seq[String])
-            (implicit ctx: mill.api.Ctx): Boolean = {
-    val compilers: Compilers = prepareCompilers(
+            (implicit ctx: ZincWorkerApi.Ctx): Boolean = {
+    withCompilers(
       scalaVersion,
-      compilerBridgeSources,
+      scalaOrganization,
       compilerClasspath,
-      scalacPluginClasspath
-    )
-    val scaladocClass = compilers.scalac().scalaInstance().loader().loadClass("scala.tools.nsc.ScalaDoc")
-    val scaladocMethod = scaladocClass.getMethod("process", classOf[Array[String]])
-    scaladocMethod.invoke(scaladocClass.newInstance(), args.toArray).asInstanceOf[Boolean]
+      scalacPluginClasspath,
+    ) { compilers: Compilers =>
+      val scaladocClass = compilers.scalac().scalaInstance().loader().loadClass("scala.tools.nsc.ScalaDoc")
+      val scaladocMethod = scaladocClass.getMethod("process", classOf[Array[String]])
+      scaladocMethod.invoke(scaladocClass.newInstance(), args.toArray).asInstanceOf[Boolean]
+    }
   }
   /** Compile the bridge if it doesn't exist yet and return the output directory.
-   *  TODO: Proper invalidation, see #389
-   */
-  def compileZincBridgeIfNeeded(scalaVersion: String,
-                                sourcesJar: os.Path,
-                                compilerJars: Array[File]): os.Path = {
-    val workingDir = ctx0.dest / scalaVersion
-    val compiledDest = workingDir / 'compiled
-    if (!os.exists(workingDir)) {
-
-      ctx0.log.info("Compiling compiler interface...")
-
-      os.makeDir.all(workingDir)
-      os.makeDir.all(compiledDest)
-
-      val sourceFolder = mill.api.IO.unpackZip(sourcesJar)(workingDir)
-      val classloader = mill.api.ClassLoader.create(compilerJars.map(_.toURI.toURL), null)(ctx0)
-      val compilerMain = classloader.loadClass(
-        if (isDotty(scalaVersion))
-          "dotty.tools.dotc.Main"
-        else
-          "scala.tools.nsc.Main"
-      )
-      val argsArray = Array[String](
-        "-d", compiledDest.toString,
-        "-classpath", (compilerJars ++ compilerBridgeClasspath).mkString(File.pathSeparator)
-      ) ++ os.walk(sourceFolder.path).filter(_.ext == "scala").map(_.toString)
-
-      compilerMain.getMethod("process", classOf[Array[String]])
-        .invoke(null, argsArray)
+    *  TODO: Proper invalidation, see #389
+    */
+  def compileZincBridgeIfNeeded(scalaVersion: String, scalaOrganization: String, compilerJars: Array[File]): os.Path = {
+    compilerBridge match{
+      case Right(compiled) => compiled(scalaVersion)
+      case Left((ctx0, compilerBridgeClasspath, srcJars)) =>
+        val workingDir = ctx0.dest / scalaVersion
+        val compiledDest = workingDir / 'compiled
+        if (!os.exists(workingDir)) {
+          ctx0.log.info("Compiling compiler interface...")
+
+          os.makeDir.all(workingDir)
+          os.makeDir.all(compiledDest)
+
+          val sourceFolder = mill.api.IO.unpackZip(srcJars(scalaVersion, scalaOrganization))(workingDir)
+          val classloader = mill.api.ClassLoader.create(compilerJars.map(_.toURI.toURL), null)(ctx0)
+          val compilerMain = classloader.loadClass(
+            if (isDotty(scalaVersion)) "dotty.tools.dotc.Main"
+            else "scala.tools.nsc.Main"
+          )
+          val argsArray = Array[String](
+            "-d", compiledDest.toString,
+            "-classpath", (compilerJars ++ compilerBridgeClasspath).mkString(File.pathSeparator)
+          ) ++ os.walk(sourceFolder.path).filter(_.ext == "scala").map(_.toString)
+
+          compilerMain.getMethod("process", classOf[Array[String]])
+            .invoke(null, argsArray)
+        }
+        compiledDest
     }
-    compiledDest
+
   }
 
 
 
-  def discoverMainClasses(compilationResult: CompilationResult)(implicit ctx: mill.api.Ctx): Seq[String] = {
+  def discoverMainClasses(compilationResult: CompilationResult)
+                         (implicit ctx: ZincWorkerApi.Ctx): Seq[String] = {
     def toScala[A](o: Optional[A]): Option[A] = if (o.isPresent) Some(o.get) else None
 
     toScala(FileAnalysisStore.binary(compilationResult.analysisFile.toIO).get())
       .map(_.getAnalysis)
       .flatMap{
         case analysis: Analysis =>
-          Some(analysis.infos.allInfos.values.map(_.getMainClasses).flatten.toSeq.sorted)
+          Some(analysis.infos.allInfos.values.flatMap(_.getMainClasses).toSeq.sorted)
         case _ =>
           None
       }
@@ -114,7 +120,7 @@ class ZincWorkerImpl(ctx0: mill.api.Ctx,
                   sources: Agg[os.Path],
                   compileClasspath: Agg[os.Path],
                   javacOptions: Seq[String])
-                 (implicit ctx: mill.api.Ctx): mill.api.Result[CompilationResult] = {
+                 (implicit ctx: ZincWorkerApi.Ctx): mill.api.Result[CompilationResult] = {
     compileInternal(
       upstreamCompileOutput,
       sources,
@@ -130,73 +136,70 @@ class ZincWorkerImpl(ctx0: mill.api.Ctx,
                    compileClasspath: Agg[os.Path],
                    javacOptions: Seq[String],
                    scalaVersion: String,
+                   scalaOrganization: String,
                    scalacOptions: Seq[String],
-                   compilerBridgeSources: os.Path,
                    compilerClasspath: Agg[os.Path],
                    scalacPluginClasspath: Agg[os.Path])
-                  (implicit ctx: mill.api.Ctx): mill.api.Result[CompilationResult] = {
-    val compilers: Compilers = prepareCompilers(
+                  (implicit ctx: ZincWorkerApi.Ctx): mill.api.Result[CompilationResult] = {
+    withCompilers(
       scalaVersion,
-      compilerBridgeSources,
+      scalaOrganization,
       compilerClasspath,
-      scalacPluginClasspath
-    )
-
-    compileInternal(
-      upstreamCompileOutput,
-      sources,
-      compileClasspath,
-      javacOptions,
-      scalacOptions = scalacPluginClasspath.map(jar => s"-Xplugin:${jar}").toSeq ++ scalacOptions,
-      compilers
-    )
+      scalacPluginClasspath,
+    ) {compilers: Compilers =>
+      compileInternal(
+        upstreamCompileOutput,
+        sources,
+        compileClasspath,
+        javacOptions,
+        scalacOptions = scalacPluginClasspath.map(jar => s"-Xplugin:$jar").toSeq ++ scalacOptions,
+        compilers
+      )
+    }
   }
 
-  private def prepareCompilers(scalaVersion: String,
-                               compilerBridgeSources: os.Path,
+  private def withCompilers[T](scalaVersion: String,
+                               scalaOrganization: String,
                                compilerClasspath: Agg[os.Path],
                                scalacPluginClasspath: Agg[os.Path])
-                              (implicit ctx: mill.api.Ctx)= {
+                              (f: Compilers => T)
+                              (implicit ctx: ZincWorkerApi.Ctx)= {
     val combinedCompilerClasspath = compilerClasspath ++ scalacPluginClasspath
     val combinedCompilerJars = combinedCompilerClasspath.toArray.map(_.toIO)
 
-    val compilerBridge = compileZincBridgeIfNeeded(
+    val compiledCompilerBridge = compileZincBridgeIfNeeded(
       scalaVersion,
-      compilerBridgeSources,
+      scalaOrganization,
       compilerClasspath.toArray.map(_.toIO)
     )
-    val compilerBridgeSig = os.mtime(compilerBridge)
+
+    val compilerBridgeSig = os.mtime(compiledCompilerBridge)
 
     val compilersSig =
       compilerBridgeSig +
         combinedCompilerClasspath.map(p => p.toString().hashCode + os.mtime(p)).sum
 
-    val compilers = mixedCompilersCache match {
-      case Some((k, v)) if k == compilersSig => v
-      case _ =>
-        val compilerName =
-          if (isDotty(scalaVersion))
-            s"dotty-compiler_${scalaBinaryVersion(scalaVersion)}"
-          else
-            "scala-compiler"
-        val scalaInstance = new ScalaInstance(
-          version = scalaVersion,
-          loader = mill.api.ClassLoader.create(combinedCompilerJars.map(_.toURI.toURL), null),
-          libraryJar = grepJar(compilerClasspath, "scala-library", scalaVersion).toIO,
-          compilerJar = grepJar(compilerClasspath, compilerName, scalaVersion).toIO,
-          allJars = combinedCompilerJars,
-          explicitActual = None
-        )
-        val compilers = ic.compilers(
-          scalaInstance,
-          ClasspathOptionsUtil.boot,
-          None,
-          ZincUtil.scalaCompiler(scalaInstance, compilerBridge.toIO)
-        )
-        mixedCompilersCache = Some((compilersSig, compilers))
-        compilers
-    }
-    compilers
+    compilerCache.withCachedValue(compilersSig){
+      val compilerJar =
+        if (isDotty(scalaVersion))
+          grepJar(compilerClasspath, s"dotty-compiler_${scalaBinaryVersion(scalaVersion)}", scalaVersion)
+        else
+          compilerJarNameGrep(compilerClasspath, scalaVersion)
+      val scalaInstance = new ScalaInstance(
+        version = scalaVersion,
+        loader = mill.api.ClassLoader.create(combinedCompilerJars.map(_.toURI.toURL), null),
+        libraryJar = libraryJarNameGrep(compilerClasspath, scalaVersion).toIO,
+        compilerJar = compilerJar.toIO,
+        allJars = combinedCompilerJars,
+        explicitActual = None
+      )
+      ic.compilers(
+        scalaInstance,
+        ClasspathOptionsUtil.boot,
+        None,
+        ZincUtil.scalaCompiler(scalaInstance, compiledCompilerBridge.toIO)
+      )
+    }(f)
   }
 
   private def compileInternal(upstreamCompileOutput: Seq[CompilationResult],
@@ -205,7 +208,7 @@ class ZincWorkerImpl(ctx0: mill.api.Ctx,
                               javacOptions: Seq[String],
                               scalacOptions: Seq[String],
                               compilers: Compilers)
-                             (implicit ctx: mill.api.Ctx): mill.api.Result[CompilationResult] = {
+                             (implicit ctx: ZincWorkerApi.Ctx): mill.api.Result[CompilationResult] = {
     os.makeDir.all(ctx.dest)
 
     val logger = {
diff --git a/scalanativelib/api/src/mill/scalanativelib/api/ScalaNativeWorkerApi.scala b/scalanativelib/api/src/ScalaNativeWorkerApi.scala
index e1fee0da..e1fee0da 100644
--- a/scalanativelib/api/src/mill/scalanativelib/api/ScalaNativeWorkerApi.scala
+++ b/scalanativelib/api/src/ScalaNativeWorkerApi.scala
diff --git a/scalanativelib/src/mill/scalanativelib/ScalaNativeModule.scala b/scalanativelib/src/ScalaNativeModule.scala
index a7a2b96b..289ba759 100644
--- a/scalanativelib/src/mill/scalanativelib/ScalaNativeModule.scala
+++ b/scalanativelib/src/ScalaNativeModule.scala
@@ -9,7 +9,7 @@ import mill.define.{Target, Task}
 import mill.api.Result
 import mill.modules.Jvm
 import mill.scalalib.{Dep, DepSyntax, Lib, SbtModule, ScalaModule, TestModule, TestRunner}
-import mill.util.Loose.Agg
+import mill.api.Loose.Agg
 import sbt.testing.{AnnotatedFingerprint, SubclassFingerprint}
 import sbt.testing.Fingerprint
 import upickle.default.{ReadWriter => RW, macroRW}
diff --git a/scalanativelib/src/mill/scalanativelib/ScalaNativeWorkerApi.scala b/scalanativelib/src/ScalaNativeWorkerApi.scala
index 80325f1e..80325f1e 100644
--- a/scalanativelib/src/mill/scalanativelib/ScalaNativeWorkerApi.scala
+++ b/scalanativelib/src/ScalaNativeWorkerApi.scala
diff --git a/scalanativelib/test/resources/hello-native-world/src/hello/ArgsParser.scala b/scalanativelib/test/resources/hello-native-world/src/ArgsParser.scala
index 8ad93598..8ad93598 100644
--- a/scalanativelib/test/resources/hello-native-world/src/hello/ArgsParser.scala
+++ b/scalanativelib/test/resources/hello-native-world/src/ArgsParser.scala
diff --git a/scalanativelib/test/resources/hello-native-world/src/hello/Main.scala b/scalanativelib/test/resources/hello-native-world/src/Main.scala
index 5e04dbb3..5e04dbb3 100644
--- a/scalanativelib/test/resources/hello-native-world/src/hello/Main.scala
+++ b/scalanativelib/test/resources/hello-native-world/src/Main.scala
diff --git a/scalanativelib/test/src/mill/scalanativelib/HelloNativeWorldTests.scala b/scalanativelib/test/src/HelloNativeWorldTests.scala
index 74d4238a..74d4238a 100644
--- a/scalanativelib/test/src/mill/scalanativelib/HelloNativeWorldTests.scala
+++ b/scalanativelib/test/src/HelloNativeWorldTests.scala
diff --git a/scalanativelib/worker/0.3/src/mill/scalanativelib/worker/ScalaNativeWorkerImpl.scala b/scalanativelib/worker/0.3/src/ScalaNativeWorkerImpl.scala
index b32e84ff..b32e84ff 100644
--- a/scalanativelib/worker/0.3/src/mill/scalanativelib/worker/ScalaNativeWorkerImpl.scala
+++ b/scalanativelib/worker/0.3/src/ScalaNativeWorkerImpl.scala