1 files changed, 4 insertions, 0 deletions
diff --git a/src/VeriFuzz/Sim/XST.hs b/src/VeriFuzz/Sim/XST.hs
index e1e8243..11be094 100644
--- a/src/VeriFuzz/Sim/XST.hs
+++ b/src/VeriFuzz/Sim/XST.hs
@@ -18,6 +18,7 @@ module VeriFuzz.Sim.XST
     )
 where
 
+import           Control.DeepSeq          (NFData, rnf, rwhnf)
 import           Data.Text                (Text, unpack)
 import           Prelude                  hiding (FilePath)
 import           Shelly
@@ -45,6 +46,9 @@ instance Synthesiser XST where
     synthOutput = xstOutput
     setSynthOutput (XST a b _) = XST a b
 
+instance NFData XST where
+    rnf = rwhnf
+
 defaultXST :: XST
 defaultXST = XST Nothing "xst" "syn_xst.v"