diff --git a/modules/core/arrow-free/src/main/kotlin/arrow/free/Free.kt b/modules/core/arrow-free/src/main/kotlin/arrow/free/Free.kt
index 1dd582f2a97..b44daaab0a6 100644
--- a/modules/core/arrow-free/src/main/kotlin/arrow/free/Free.kt
+++ b/modules/core/arrow-free/src/main/kotlin/arrow/free/Free.kt
@@ -2,10 +2,10 @@ package arrow.free
 
 import arrow.Kind
 import arrow.core.Either
+import arrow.core.FunctionK
 import arrow.core.identity
 import arrow.higherkind
 import arrow.typeclasses.Applicative
-import arrow.core.FunctionK
 import arrow.typeclasses.Monad
 
 inline fun <M, S, A> FreeOf<S, A>.foldMapK(f: FunctionK<S, M>, MM: Monad<M>): Kind<M, A> =
@@ -79,20 +79,20 @@ tailrec fun <S, A> Free<S, A>.step(): Free<S, A> =
   }
 
 @Suppress("UNCHECKED_CAST")
-fun <M, S, A> Free<S, A>.foldMap(f: FunctionK<S, M>, MM: Monad<M>): Kind<M, A> = MM.run {
-  tailRecM(this@foldMap) {
+fun <M, S, A> Free<S, A>.foldMap(f: FunctionK<S, M>, MM: Monad<M>): Kind<M, A> =
+  MM.tailRecM(this@foldMap) {
     val x = it.step()
     when (x) {
-      is Free.Pure<S, A> -> just(Either.Right(x.a))
-      is Free.Suspend<S, A> -> f(x.a).map({ Either.Right(it) })
+      is Free.Pure<S, A> -> MM.just(Either.Right(x.a))
+      is Free.Suspend<S, A> -> MM.run { f(x.a).map { Either.Right(it) } }
       is Free.FlatMapped<S, A, *> -> {
         val g = (x.fm as (A) -> Free<S, A>)
         val c = x.c as Free<S, A>
-        c.foldMap(f, MM).map({ cc -> Either.Left(g(cc)) })
+        val folded = c.foldMap(f, MM)
+        MM.run { folded.map { cc -> Either.Left(g(cc)) } }
       }
     }
   }
-}
 
 fun <S, A> A.free(): Free<S, A> = Free.just<S, A>(this)
 
diff --git a/modules/core/arrow-mtl/src/main/kotlin/arrow/mtl/instances/option.kt b/modules/core/arrow-mtl/src/main/kotlin/arrow/mtl/instances/option.kt
index 87820dd9ebf..088a27432d0 100644
--- a/modules/core/arrow-mtl/src/main/kotlin/arrow/mtl/instances/option.kt
+++ b/modules/core/arrow-mtl/src/main/kotlin/arrow/mtl/instances/option.kt
@@ -14,16 +14,16 @@ interface OptionTraverseFilterInstance : TraverseFilter<ForOption> {
   override fun <A> Kind<ForOption, A>.filter(f: (A) -> Boolean): Option<A> =
     fix().filter(f)
 
-  override fun <G, A, B> Kind<ForOption, A>.traverseFilter(AP: Applicative<G>, f: (A) -> Kind<G, Option<B>>): arrow.Kind<G, Option<B>> =
+  override fun <G, A, B> Kind<ForOption, A>.traverseFilter(AP: Applicative<G>, f: (A) -> Kind<G, Option<B>>): Kind<G, Option<B>> =
     optionTraverseFilter(AP, f)
 
   override fun <A, B> Kind<ForOption, A>.map(f: (A) -> B): Option<B> =
     fix().map(f)
 
-  override fun <G, A, B> Kind<ForOption, A>.traverse(AP: Applicative<G>, f: (A) -> Kind<G, B>): arrow.Kind<G, Option<B>> =
+  override fun <G, A, B> Kind<ForOption, A>.traverse(AP: Applicative<G>, f: (A) -> Kind<G, B>): Kind<G, Option<B>> =
     optionTraverse(AP, f)
 
-  override fun <A> Kind<ForOption, A>.exists(p: (A) -> Boolean): kotlin.Boolean =
+  override fun <A> Kind<ForOption, A>.exists(p: (A) -> Boolean): Boolean =
     fix().exists(p)
 
   override fun <A, B> Kind<ForOption, A>.foldLeft(b: B, f: (B, A) -> B): B =
@@ -32,13 +32,13 @@ interface OptionTraverseFilterInstance : TraverseFilter<ForOption> {
   override fun <A, B> Kind<ForOption, A>.foldRight(lb: Eval<B>, f: (A, Eval<B>) -> Eval<B>): Eval<B> =
     fix().foldRight(lb, f)
 
-  override fun <A> OptionOf<A>.forAll(p: (A) -> Boolean): kotlin.Boolean =
+  override fun <A> OptionOf<A>.forAll(p: (A) -> Boolean): Boolean =
     fix().forall(p)
 
-  override fun <A> Kind<ForOption, A>.isEmpty(): kotlin.Boolean =
+  override fun <A> Kind<ForOption, A>.isEmpty(): Boolean =
     fix().isEmpty()
 
-  override fun <A> Kind<ForOption, A>.nonEmpty(): kotlin.Boolean =
+  override fun <A> Kind<ForOption, A>.nonEmpty(): Boolean =
     fix().nonEmpty()
 }
 
@@ -71,7 +71,7 @@ object OptionMtlContext : OptionMonadFilterInstance, OptionTraverseFilterInstanc
     fix().filter(f)
 
   override fun <A, B> Kind<ForOption, A>.mapFilter(f: (A) -> Option<B>): Option<B> =
-    this.flatMap({ a -> f(a).fold({ empty<B>() }, { just(it) }) })
+    flatMap { a -> f(a).fold({ empty<B>() }, { just(it) }) }
 
   override fun <A, B> Kind<ForOption, A>.map(f: (A) -> B): Option<B> =
     fix().map(f)
diff --git a/modules/core/arrow-mtl/src/main/kotlin/arrow/mtl/instances/optiont.kt b/modules/core/arrow-mtl/src/main/kotlin/arrow/mtl/instances/optiont.kt
index 9939eece3cd..76195083cf0 100644
--- a/modules/core/arrow-mtl/src/main/kotlin/arrow/mtl/instances/optiont.kt
+++ b/modules/core/arrow-mtl/src/main/kotlin/arrow/mtl/instances/optiont.kt
@@ -39,9 +39,9 @@ interface OptionTTraverseFilterInstance<F> :
     fix().traverseFilter(f, AP, FFF())
 }
 
-fun <F, G, A, B> OptionT<F, A>.traverseFilter(f: (A) -> Kind<G, Option<B>>, GA: Applicative<G>, FF: Traverse<F>): Kind<G, OptionT<F, B>> = GA.run {
+fun <F, G, A, B> OptionT<F, A>.traverseFilter(f: (A) -> Kind<G, Option<B>>, GA: Applicative<G>, FF: Traverse<F>): Kind<G, OptionT<F, B>> {
   val fa = ComposedTraverseFilter(FF, Option.traverseFilter(), Option.applicative()).traverseFilterC(value, f, GA)
-  fa.map({ OptionT(FF.run { it.unnest().map({ it.fix() }) }) })
+  return GA.run { fa.map { OptionT(FF.run { it.unnest().map { it.fix() } }) } }
 }
 
 class OptionTMtlContext<F>(val MF: Monad<F>, val TF: TraverseFilter<F>) : OptionTMonadInstance<F>, OptionTMonoidKInstance<F>, OptionTTraverseFilterInstance<F> {
diff --git a/modules/effects/arrow-effects-reactor/src/main/kotlin/arrow/effects/CoroutineContextScheduler.kt b/modules/effects/arrow-effects-reactor/src/main/kotlin/arrow/effects/CoroutineContextReactorScheduler.kt
similarity index 97%
rename from modules/effects/arrow-effects-reactor/src/main/kotlin/arrow/effects/CoroutineContextScheduler.kt
rename to modules/effects/arrow-effects-reactor/src/main/kotlin/arrow/effects/CoroutineContextReactorScheduler.kt
index d6637ecbe91..77bc2a0a459 100644
--- a/modules/effects/arrow-effects-reactor/src/main/kotlin/arrow/effects/CoroutineContextScheduler.kt
+++ b/modules/effects/arrow-effects-reactor/src/main/kotlin/arrow/effects/CoroutineContextReactorScheduler.kt
@@ -6,7 +6,7 @@ import kotlin.coroutines.experimental.Continuation
 import kotlin.coroutines.experimental.CoroutineContext
 import kotlin.coroutines.experimental.startCoroutine
 
-object CoroutineContextScheduler {
+object CoroutineContextReactorScheduler {
   private interface NonCancellableContinuation : Continuation<Unit>, Disposable
 
   private val emptyDisposable = object : Disposable {
diff --git a/modules/effects/arrow-effects-reactor/src/main/kotlin/arrow/effects/FluxK.kt b/modules/effects/arrow-effects-reactor/src/main/kotlin/arrow/effects/FluxK.kt
index b893ec4784d..3ae01919f0a 100644
--- a/modules/effects/arrow-effects-reactor/src/main/kotlin/arrow/effects/FluxK.kt
+++ b/modules/effects/arrow-effects-reactor/src/main/kotlin/arrow/effects/FluxK.kt
@@ -6,7 +6,7 @@ import arrow.core.Eval
 import arrow.core.Left
 import arrow.core.Right
 import arrow.core.identity
-import arrow.effects.CoroutineContextScheduler.asScheduler
+import arrow.effects.CoroutineContextReactorScheduler.asScheduler
 import arrow.effects.typeclasses.Proc
 import arrow.higherkind
 import arrow.typeclasses.Applicative
diff --git a/modules/effects/arrow-effects-reactor/src/main/kotlin/arrow/effects/MonoK.kt b/modules/effects/arrow-effects-reactor/src/main/kotlin/arrow/effects/MonoK.kt
index 45fd982df97..6a6f06bf2e9 100644
--- a/modules/effects/arrow-effects-reactor/src/main/kotlin/arrow/effects/MonoK.kt
+++ b/modules/effects/arrow-effects-reactor/src/main/kotlin/arrow/effects/MonoK.kt
@@ -3,7 +3,7 @@ package arrow.effects
 import arrow.core.Either
 import arrow.core.Either.Left
 import arrow.core.Either.Right
-import arrow.effects.CoroutineContextScheduler.asScheduler
+import arrow.effects.CoroutineContextReactorScheduler.asScheduler
 import arrow.effects.typeclasses.Proc
 import arrow.higherkind
 import reactor.core.publisher.Mono
diff --git a/modules/effects/arrow-effects-rx2/src/main/kotlin/arrow/effects/CoroutineContextScheduler.kt b/modules/effects/arrow-effects-rx2/src/main/kotlin/arrow/effects/CoroutineContextRx2Scheduler.kt
similarity index 97%
rename from modules/effects/arrow-effects-rx2/src/main/kotlin/arrow/effects/CoroutineContextScheduler.kt
rename to modules/effects/arrow-effects-rx2/src/main/kotlin/arrow/effects/CoroutineContextRx2Scheduler.kt
index e976502d276..54d154921c1 100644
--- a/modules/effects/arrow-effects-rx2/src/main/kotlin/arrow/effects/CoroutineContextScheduler.kt
+++ b/modules/effects/arrow-effects-rx2/src/main/kotlin/arrow/effects/CoroutineContextRx2Scheduler.kt
@@ -8,7 +8,7 @@ import kotlin.coroutines.experimental.Continuation
 import kotlin.coroutines.experimental.CoroutineContext
 import kotlin.coroutines.experimental.startCoroutine
 
-object CoroutineContextScheduler {
+object CoroutineContextRx2Scheduler {
   private interface NonCancellableContinuation : Continuation<Unit>, Disposable
 
   fun CoroutineContext.asScheduler(): Scheduler =
diff --git a/modules/effects/arrow-effects-rx2/src/main/kotlin/arrow/effects/FlowableK.kt b/modules/effects/arrow-effects-rx2/src/main/kotlin/arrow/effects/FlowableK.kt
index c55cae4a09d..3d1f119839a 100644
--- a/modules/effects/arrow-effects-rx2/src/main/kotlin/arrow/effects/FlowableK.kt
+++ b/modules/effects/arrow-effects-rx2/src/main/kotlin/arrow/effects/FlowableK.kt
@@ -2,7 +2,7 @@ package arrow.effects
 
 import arrow.Kind
 import arrow.core.*
-import arrow.effects.CoroutineContextScheduler.asScheduler
+import arrow.effects.CoroutineContextRx2Scheduler.asScheduler
 import arrow.effects.typeclasses.Proc
 import arrow.higherkind
 import arrow.typeclasses.Applicative
@@ -44,11 +44,10 @@ data class FlowableK<A>(val flowable: Flowable<A>) : FlowableKOf<A>, FlowableKKi
     return Eval.defer { loop(this) }
   }
 
-  fun <G, B> traverse(GA: Applicative<G>, f: (A) -> Kind<G, B>): Kind<G, FlowableK<B>> = GA.run {
-    foldRight(Eval.always { just(Flowable.empty<B>().k()) }) { a, eval ->
-      f(a).map2Eval(eval) { Flowable.concat(Flowable.just<B>(it.a), it.b.flowable).k() }
+  fun <G, B> traverse(GA: Applicative<G>, f: (A) -> Kind<G, B>): Kind<G, FlowableK<B>> =
+    foldRight(Eval.always { GA.just(Flowable.empty<B>().k()) }) { a, eval ->
+      GA.run { f(a).map2Eval(eval) { Flowable.concat(Flowable.just<B>(it.a), it.b.flowable).k() } }
     }.value()
-  }
 
   fun handleErrorWith(function: (Throwable) -> FlowableK<A>): FlowableK<A> =
     flowable.onErrorResumeNext { t: Throwable -> function(t).flowable }.k()
diff --git a/modules/effects/arrow-effects-rx2/src/main/kotlin/arrow/effects/MaybeK.kt b/modules/effects/arrow-effects-rx2/src/main/kotlin/arrow/effects/MaybeK.kt
index 0218b4d6eec..379cb9a77bc 100644
--- a/modules/effects/arrow-effects-rx2/src/main/kotlin/arrow/effects/MaybeK.kt
+++ b/modules/effects/arrow-effects-rx2/src/main/kotlin/arrow/effects/MaybeK.kt
@@ -1,7 +1,7 @@
 package arrow.effects
 
 import arrow.core.*
-import arrow.effects.CoroutineContextScheduler.asScheduler
+import arrow.effects.CoroutineContextRx2Scheduler.asScheduler
 import arrow.effects.typeclasses.Proc
 import arrow.higherkind
 import io.reactivex.Maybe
diff --git a/modules/effects/arrow-effects-rx2/src/main/kotlin/arrow/effects/ObservableK.kt b/modules/effects/arrow-effects-rx2/src/main/kotlin/arrow/effects/ObservableK.kt
index 664d7ac332a..5378f82c9c2 100644
--- a/modules/effects/arrow-effects-rx2/src/main/kotlin/arrow/effects/ObservableK.kt
+++ b/modules/effects/arrow-effects-rx2/src/main/kotlin/arrow/effects/ObservableK.kt
@@ -2,13 +2,13 @@ package arrow.effects
 
 import arrow.Kind
 import arrow.core.*
+import arrow.effects.CoroutineContextRx2Scheduler.asScheduler
 import arrow.effects.typeclasses.Proc
 import arrow.higherkind
 import arrow.typeclasses.Applicative
 import io.reactivex.Observable
 import io.reactivex.ObservableEmitter
 import kotlin.coroutines.experimental.CoroutineContext
-import arrow.effects.CoroutineContextScheduler.asScheduler
 
 fun <A> Observable<A>.k(): ObservableK<A> = ObservableK(this)
 
@@ -43,11 +43,10 @@ data class ObservableK<A>(val observable: Observable<A>) : ObservableKOf<A>, Obs
     return Eval.defer { loop(this) }
   }
 
-  fun <G, B> traverse(GA: Applicative<G>, f: (A) -> Kind<G, B>): Kind<G, ObservableK<B>> = GA.run {
+  fun <G, B> traverse(GA: Applicative<G>, f: (A) -> Kind<G, B>): Kind<G, ObservableK<B>> =
     foldRight(Eval.always { GA.just(Observable.empty<B>().k()) }) { a, eval ->
-      f(a).map2Eval(eval) { Observable.concat(Observable.just<B>(it.a), it.b.observable).k() }
+      GA.run { f(a).map2Eval(eval) { Observable.concat(Observable.just<B>(it.a), it.b.observable).k() } }
     }.value()
-  }
 
   fun handleErrorWith(function: (Throwable) -> ObservableK<A>): ObservableK<A> =
     this.fix().observable.onErrorResumeNext { t: Throwable -> function(t).observable }.k()
diff --git a/modules/effects/arrow-effects-rx2/src/main/kotlin/arrow/effects/SingleK.kt b/modules/effects/arrow-effects-rx2/src/main/kotlin/arrow/effects/SingleK.kt
index 85c3d15ec09..a36a3ed44f7 100644
--- a/modules/effects/arrow-effects-rx2/src/main/kotlin/arrow/effects/SingleK.kt
+++ b/modules/effects/arrow-effects-rx2/src/main/kotlin/arrow/effects/SingleK.kt
@@ -3,7 +3,7 @@ package arrow.effects
 import arrow.core.Either
 import arrow.core.Left
 import arrow.core.Right
-import arrow.effects.CoroutineContextScheduler.asScheduler
+import arrow.effects.CoroutineContextRx2Scheduler.asScheduler
 import arrow.effects.typeclasses.Proc
 import arrow.higherkind
 import io.reactivex.Single