diff --git a/testsuite/tests/ghc-regress/th/TH_repPrimOutput.hs b/testsuite/tests/ghc-regress/th/TH_repPrimOutput.hs
index c5c33066045e471444258f846cddafe329504309..28d12d20a0d07a8bf025835501ec663793876e51 100644
--- a/testsuite/tests/ghc-regress/th/TH_repPrimOutput.hs
+++ b/testsuite/tests/ghc-regress/th/TH_repPrimOutput.hs
@@ -8,6 +8,7 @@ import GHC.Base
 import GHC.Float
 import Language.Haskell.THSyntax
 import Text.PrettyPrint
+import System.IO
 
 main :: IO ()
 main = do putStrLn $ show $ $( do e <- [| I# 20# |]