diff --git a/async/shared/src/main/scala/dev/tauri/choam/async/AsyncReactive.scala b/async/shared/src/main/scala/dev/tauri/choam/async/AsyncReactive.scala
index 7876c2543..78b112cf3 100644
--- a/async/shared/src/main/scala/dev/tauri/choam/async/AsyncReactive.scala
+++ b/async/shared/src/main/scala/dev/tauri/choam/async/AsyncReactive.scala
@@ -63,7 +63,7 @@ object AsyncReactive {
     final override def promise[A]: Axn[Promise[F, A]] =
       Promise.forAsync[F, A](this, F)
 
-    final override def monadCancel =
+    final override def monadCancel: MonadCancel[F, Throwable] =
       F
   }
 }
diff --git a/async/shared/src/main/scala/dev/tauri/choam/async/OverflowQueue.scala b/async/shared/src/main/scala/dev/tauri/choam/async/OverflowQueue.scala
index 60ad87923..bd401c0cf 100644
--- a/async/shared/src/main/scala/dev/tauri/choam/async/OverflowQueue.scala
+++ b/async/shared/src/main/scala/dev/tauri/choam/async/OverflowQueue.scala
@@ -18,6 +18,8 @@
 package dev.tauri.choam
 package async
 
+import cats.effect.std.{ Queue => CatsQueue }
+
 abstract class OverflowQueue[F[_], A]
   extends UnboundedQueue.WithSize[F, A] {
 
@@ -62,7 +64,7 @@ object OverflowQueue {
     final override def size: F[Int] =
       F.run(buff.size)
 
-    final override def toCats =
+    final override def toCats: CatsQueue[F, A] =
       new AsyncQueue.CatsQueueAdapter(this)
 
     final override def tryEnqueue: Rxn[A, Boolean] =
@@ -87,7 +89,7 @@ object OverflowQueue {
     final def size: F[Int] =
       F.run(q.size)
 
-    final def toCats =
+    final def toCats: CatsQueue[F, A] =
       new AsyncQueue.CatsQueueAdapter(this)
 
     final def tryEnqueue: Rxn[A, Boolean] =
diff --git a/async/shared/src/main/scala/dev/tauri/choam/async/UnboundedQueue.scala b/async/shared/src/main/scala/dev/tauri/choam/async/UnboundedQueue.scala
index d772878b3..b97bd4167 100644
--- a/async/shared/src/main/scala/dev/tauri/choam/async/UnboundedQueue.scala
+++ b/async/shared/src/main/scala/dev/tauri/choam/async/UnboundedQueue.scala
@@ -64,7 +64,7 @@ object UnboundedQueue {
             F.monad.widen(wl.asyncGet)
           final override def size: F[Int] =
             q.size.run[F]
-          final override def toCats =
+          final override def toCats: CatsQueue[F, A] =
             new AsyncQueue.CatsQueueAdapter(this)
         }
       }
diff --git a/bench/src/main/scala/dev/tauri/choam/bench/DataMapBench.scala b/bench/src/main/scala/dev/tauri/choam/bench/DataMapBench.scala
index c51754f90..e122db809 100644
--- a/bench/src/main/scala/dev/tauri/choam/bench/DataMapBench.scala
+++ b/bench/src/main/scala/dev/tauri/choam/bench/DataMapBench.scala
@@ -439,24 +439,24 @@ object DataMapBench {
   @State(Scope.Benchmark)
   class ChmSt extends JucCmSt {
 
-    import java.util.concurrent.ConcurrentHashMap
+    import java.util.concurrent.{ ConcurrentMap, ConcurrentHashMap }
 
     private[this] val chm: ConcurrentHashMap[String, String] =
       new ConcurrentHashMap[String, String]
 
-    final override def cm =
+    final override def cm: ConcurrentMap[String, String] =
       chm
   }
 
   @State(Scope.Benchmark)
   class CslmSt extends JucCmSt {
 
-    import java.util.concurrent.ConcurrentSkipListMap
+    import java.util.concurrent.{ ConcurrentMap, ConcurrentSkipListMap }
 
     val cslm: ConcurrentSkipListMap[String, String] =
       new ConcurrentSkipListMap[String, String]
 
-    final override def cm =
+    final override def cm:ConcurrentMap[String, String] =
       cslm
   }
 
diff --git a/core/shared/src/main/scala/dev/tauri/choam/core/Reactive.scala b/core/shared/src/main/scala/dev/tauri/choam/core/Reactive.scala
index 67faf1b5f..bf3aa55a5 100644
--- a/core/shared/src/main/scala/dev/tauri/choam/core/Reactive.scala
+++ b/core/shared/src/main/scala/dev/tauri/choam/core/Reactive.scala
@@ -53,7 +53,7 @@ object Reactive {
       }
     }
 
-    final override def monad =
+    final override def monad: Monad[F] =
       F
   }
 
diff --git a/mcas/shared/src/main/scala/dev/tauri/choam/internal/mcas/LogMap.scala b/mcas/shared/src/main/scala/dev/tauri/choam/internal/mcas/LogMap.scala
index 11a8aa045..db0825b38 100644
--- a/mcas/shared/src/main/scala/dev/tauri/choam/internal/mcas/LogMap.scala
+++ b/mcas/shared/src/main/scala/dev/tauri/choam/internal/mcas/LogMap.scala
@@ -49,7 +49,7 @@ private object LogMap {
     final override def size =
       0
 
-    final override def valuesIterator =
+    final override def valuesIterator: Iterator[HalfWordDescriptor[_]] =
       Iterator.empty
 
     final override def nonEmpty =