diff --git a/io-sim/src/Control/Monad/IOSim/Internal.hs b/io-sim/src/Control/Monad/IOSim/Internal.hs
index 2565eab3..8557136a 100644
--- a/io-sim/src/Control/Monad/IOSim/Internal.hs
+++ b/io-sim/src/Control/Monad/IOSim/Internal.hs
@@ -1236,9 +1236,8 @@ execNewTVar !tvarId !mbLabel x = do
     !tvarBlocked <- newSTRef ([], Set.empty)
     !tvarVClock  <- newSTRef $! VectorClock Map.empty
     !tvarTrace   <- newSTRef $! Nothing
-    return TVar {tvarId, tvarLabel,
-                 tvarCurrent, tvarUndo, tvarBlocked, tvarVClock,
-                 tvarTrace}
+    return TVar {tvarId, tvarLabel, tvarCurrent, tvarUndo, tvarBlocked,
+                 tvarVClock, tvarTrace}
 
 
 -- 'execReadTVar' is defined in `Control.Monad.IOSim.Type` and shared with /IOSimPOR/
diff --git a/io-sim/src/Control/Monad/IOSimPOR/Internal.hs b/io-sim/src/Control/Monad/IOSimPOR/Internal.hs
index 56e3c963..72409a6b 100644
--- a/io-sim/src/Control/Monad/IOSimPOR/Internal.hs
+++ b/io-sim/src/Control/Monad/IOSimPOR/Internal.hs
@@ -561,8 +561,8 @@ schedule thread@Thread{
           timers' = PSQ.insert nextTmid expiry (Timer tvar) timers
           thread' = thread { threadControl = ThreadControl (k t) ctl }
       trace <- schedule thread' simstate { timers   = timers'
-                                          , nextVid  = succ (succ nextVid)
-                                          , nextTmid = succ nextTmid }
+                                         , nextVid  = succ (succ nextVid)
+                                         , nextTmid = succ nextTmid }
       return (SimPORTrace time tid tstep tlbl (EventTimerCreated nextTmid (TVarId nextVid) expiry) trace)
 
     CancelTimeout (Timeout tvar tmid) k -> do
@@ -1849,7 +1849,8 @@ normalizeRaces Races{ activeRaces, completeRaces } =
                         $ activeRaces
                         )
                      ++ completeRaces
-  in Races{ activeRaces = activeRaces', completeRaces = completeRaces' }
+  in Races{ activeRaces   = activeRaces',
+            completeRaces = completeRaces' }
 
 
 -- When a thread terminates, we remove it from the concurrent thread
diff --git a/io-sim/src/Control/Monad/IOSimPOR/Types.hs b/io-sim/src/Control/Monad/IOSimPOR/Types.hs
index 228be12d..772acb51 100644
--- a/io-sim/src/Control/Monad/IOSimPOR/Types.hs
+++ b/io-sim/src/Control/Monad/IOSimPOR/Types.hs
@@ -69,15 +69,9 @@ instance Monoid Effect where
 -- Effect smart constructors
 --
 
--- readEffect :: SomeTVar s -> Effect
--- readEffect r = mempty{effectReads = Set.singleton $ someTvarId r }
-
 readEffects :: [Labelled (SomeTVar s)] -> Effect
 readEffects rs = mempty{effectReads = Set.fromList (map (someTvarId <$>) rs)}
 
--- writeEffect :: SomeTVar s -> Effect
--- writeEffect r = mempty{effectWrites = Set.singleton $ someTvarId r }
-
 writeEffects :: [Labelled (SomeTVar s)] -> Effect
 writeEffects rs = mempty{effectWrites = Set.fromList (map (someTvarId <$>) rs)}
 
@@ -224,11 +218,18 @@ data StepInfo = StepInfo {
 -- Races
 --
 
-data Races = Races { -- These steps may still race with future steps
-                     activeRaces   :: ![StepInfo],
-                     -- These steps cannot be concurrent with future steps
-                     completeRaces :: ![StepInfo]
-                   }
+-- | Information about all discovered races in a simulation categorised as
+-- active and complete races.
+--
+-- See 'normalizeRaces' how we split `StepInfo` into the two categories.
+--
+data Races = Races {
+    -- | These steps may still race with future steps.
+    activeRaces   :: ![StepInfo],
+
+    -- | These steps cannot be concurrent with future steps.
+    completeRaces :: ![StepInfo]
+  }
   deriving Show
 
 noRaces :: Races