[project @ 2002-05-28 14:04:18 by simonmar]

[ghc-base.git] / Control / Exception.hs

diff --git a/Control/Exception.hs b/Control/Exception.hs
index 5231db4..be7595e 100644 (file)
--- a/Control/Exception.hs
+++ b/Control/Exception.hs
@@ -223,7 +223,10 @@ handleJust p =  flip (catchJust p)
 --
 -- NOTE: @(evaluate a)@ is /not/ the same as @(a \`seq\` return a)@.
 evaluate :: a -> IO a
-evaluate a = IO $ \s -> a `seq` (# s, a #)
+evaluate a = IO $ \s -> case a `seq` () of () -> (# s, a #)
+       -- NB. can't write  
+       --      a `seq` (# s, a #)
+       -- because we can't have an unboxed tuple as a function argument
 
 -----------------------------------------------------------------------------
 -- 'try' and variations.