no need to hide 'catch'

[michaelt]

This doesn't normally cause a problem because of some ghc workaround special to this case, but I was able to trigger an error with a complicated mixture of sandboxing, directing cabal to a locally installed ghc, and something else. catch isn't actually used in the file, so it seems it might as well go.

[jgm]

I believe the hiding is still needed for older GHC versions,
with older versions of base, in which pandoc exports 'catch'.
So the hiding should probably be kept but made conditional on
the MIN_VERSION_base using cpp macros.

[michaelt]

My thought was that there can't be a problem, since Control.Exception isn't imported and no other catch is in scope. It seems catch was once used in this file but was dropped here b3ad94b#diff-8288955e209cfbead5b318a8598be9c0

I see that more than one approach is taken in pandoc. We find

pandoc/man/make-pandoc-man-pages.hs:import Prelude hiding (catch)
pandoc/src/Text/Pandoc/Writers/EPUB.hs:64:import Prelude hiding (catch)

where Control.Exception.catch is brought in scope; and

pandoc/src/Text/Pandoc/UTF8.hs:55:                       catch)

where it isn't (so the complicated cpp bit distinguishing older and newer versions of base) mustn't be necessary).

Nothing much hangs on it, but I could make a patch regularizing things to use the foolproof import qualified Control.Exception as E approach found in e.g.

 pandoc/pandoc.hs:1057:                           E.catch (UTF8.readFile tp')

and some other places.

[jgm]

I commented without looking closely enough at your patch. You are right. The line isn't needed.
Thanks!