1 files changed, 1 insertions, 1 deletions

diff --git a/src/Control/Concurrent/Lifted/Instrument.hs b/src/Control/Concurrent/Lifted/Instrument.hs
index 7ee78c8b..9a409569 100644
--- a/src/Control/Concurrent/Lifted/Instrument.hs
+++ b/src/Control/Concurrent/Lifted/Instrument.hs
@@ -25,7 +25,7 @@ data PerThread = PerThread
  }
  deriving (Eq,Ord,Show)
 
-data GlobalState = GlobalState
+newtype GlobalState = GlobalState
  { threads :: Map.Map ThreadId PerThread
  }