diff --git a/libs/base/Control/Monad/RWS/CPS.idr b/libs/base/Control/Monad/RWS/CPS.idr
index f97f80142..2e10a9958 100644
--- a/libs/base/Control/Monad/RWS/CPS.idr
+++ b/libs/base/Control/Monad/RWS/CPS.idr
@@ -90,7 +90,7 @@ execRWS m r s = let (_,s1,w) = runRWS m r s
 public export %inline
 mapRWS :  (Monoid w, Semigroup w')
        => ((a, s, w) -> (b, s, w')) -> RWS r w s a -> RWS r w' s b
-mapRWS f = mapRWST (Id . f . runIdentity)
+mapRWS f = mapRWST \(Id p) => Id (f p)
 
 ||| `withRWS f m` executes action `m` with an initial environment
 ||| and state modified by applying `f`.
diff --git a/libs/base/Control/Monad/State/State.idr b/libs/base/Control/Monad/State/State.idr
index 438110412..816ef4c3b 100644
--- a/libs/base/Control/Monad/State/State.idr
+++ b/libs/base/Control/Monad/State/State.idr
@@ -59,7 +59,7 @@ execState s = fst . runState s
 ||| the given function.
 public export %inline
 mapState : ((s, a) -> (s, b)) -> State s a -> State s b
-mapState f = mapStateT (Id . f . runIdentity)
+mapState f = mapStateT \(Id p) => Id (f p)
 
 --------------------------------------------------------------------------------
 --          Implementations
diff --git a/libs/base/Control/Monad/Writer/CPS.idr b/libs/base/Control/Monad/Writer/CPS.idr
index 9db0d477e..82e65dbb6 100644
--- a/libs/base/Control/Monad/Writer/CPS.idr
+++ b/libs/base/Control/Monad/Writer/CPS.idr
@@ -70,7 +70,7 @@ execWriter = runIdentity . execWriterT
 public export %inline
 mapWriter :  (Monoid w, Semigroup w')
           => ((a, w) -> (b, w')) -> Writer w a -> Writer w' b
-mapWriter f = mapWriterT (Id . f . runIdentity)
+mapWriter f = mapWriterT \(Id p) => Id (f p)
 
 --------------------------------------------------------------------------------
 --          Implementations