Treat modified Binary UserData as a local state with a sub-actionwip/binary-reader/step1

1 files changed, 2 insertions, 4 deletions

diff --git a/compiler/iface/BinFingerprint.hs b/compiler/iface/BinFingerprint.hs
index 1eef4d67b4..11b6556d4d 100644
--- a/compiler/iface/BinFingerprint.hs
+++ b/compiler/iface/BinFingerprint.hs
@@ -33,13 +33,11 @@ computeFingerprint :: (Binary a)
                    -> a
                    -> IO Fingerprint
 computeFingerprint put_nonbinding_name a = do
-    bh <- fmap set_user_data $ openBinMem (3*1024) -- just less than a block
+  bh <- openBinMem (3*1024)
+  writeState bh put_nonbinding_name putNameLiterally putFS $ \bh -> do
     put_ bh a
     fp <- fingerprintBinMem bh
     return fp
-  where
-    set_user_data bh =
-      setUserData bh $ newWriteState put_nonbinding_name putNameLiterally putFS
 
 -- | Used when we want to fingerprint a structure without depending on the
 -- fingerprints of external Names that it refers to.