Weird behavior with bracket and global IORef

18

I’d abstract message over something that is used insid the unsafePerformIO block, e.g.,

message :: IORef Bool -> String
message ref = unsafePerformIO $ readIORef re >>= ...
{-# NOINLINE message #-}

Of course the problem at use sites is then that we will likely float message isSetRef to top-level and we end up where we began, so we’d need the hypothetical noupdate:

main = do
  let before = setMessage
  let after () = unsetMessage
  let thing () = print (noupdate $ \hide -> message (hide isSetRef))
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