diff --git a/ghc/lib/std/PrelBase.lhs b/ghc/lib/std/PrelBase.lhs
index 3f5bc1df2d59c9aac4c4f0f967e92317a8aa5174..2d504bceff0c4a0c2eaf66890fbb9527b51bd50c 100644
--- a/ghc/lib/std/PrelBase.lhs
+++ b/ghc/lib/std/PrelBase.lhs
@@ -791,7 +791,7 @@ intToDigit :: Int -> Char
 intToDigit i
  | i >= 0  && i <=  9   =  toEnum (fromEnum '0' + i)
  | i >= 10 && i <= 15   =  toEnum (fromEnum 'a' + i -10)
- | otherwise		=  error "Char.intToDigit: not a digit" ++ show i)
+ | otherwise		=  error ("Char.intToDigit: not a digit" ++ show i)
 
 \end{code}