thenIO removal

Joachim Breitner mail at
Mon Nov 3 08:22:08 UTC 2014


Am Sonntag, den 02.11.2014, 20:10 -0500 schrieb David Feuer:
> GHC.Base has a function, thenIO, that isn't used anywhere in the
> libraries or compiler, and isn't exported anywhere "public". But for
> some reason, it's listed in compiler/prelude/PrelNames.lhs, which
> causes a validation failure if I remove it. Is there a reason that a
> completely unused function is wired in? Is it a historical artifact,
> or an optimization that was never completed, or something else? Should
> I wipe it out of PrelNames, or do we want to use it for something?

I find uses in compiler/typecheck/TcRnDriver.lhs in tcUserStmt, it seems
to be related to ghci’s support for IO actions. If you can rewrite that
easily, then it surely can go, but there likely is a reason for it. If
you find that reason, a Note would be appreciated.


Joachim “nomeata” Breitner
  mail at joachim-breitner.de
  Jabber: nomeata at  • GPG-Key: 0xF0FBF51F
  Debian Developer: nomeata at

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