GHC 7.7 warnings

[haskell]

GHC 7.7 warnings

[tibbe]

I think what we'll do is once 7.8 is out we'll #ifdef a

import Prelude hiding (join)

for GHC >= 7.8.

[hvr]

I'm afraid that won't silence the warning... I just tried with GHC HEAD with the following dummy module:

module Foo (join) where

import Prelude ()

join :: ()
join = ()

See also GHC #8004 for details about this new "feature".

[tibbe]

Ugh. Why not? What are you supposed to do?

[foxik]

Maybe we can just rename join. That way we would not need any preprocessor magic.

[tibbe]

I'm OK with that, but I also want to follow up with GHC HQ to see why the fix (hide the import) doesn't work. How about glue instead of join? :)

[hvr]

@tibbe Fwiw, you could also add an ifdef'ed {-# OPTIONS_GHC -fno-warn-amp #-} to that module; but please, follow up on that GHC ticket.

[foxik]

We already use glue in Set and Map which is join without a root, i.e.,

glue :: Map k a -> Map k a -> Map k a
join :: k -> a -> Map k a -> Map k a -> Map k a

What about link? We could also use node if we rename the node used in printing...

[tibbe]

I don't care much either way as long as the function is documented clearly and we don't break the public API.

[foxik]

Thanks Johan for commenting GHC #8004. Lets wait and see if the GHC behaviour is modified and if so, use your first suggestion import Prelude hiding (join).

[foxik]

Just pushed the changes to silense the warnings. I do not have build of GHC 7.7, so I only hope the warnings will be gone. If not, please reopen the issue.

Update: the commits are 5b7e912, 501fa5b and c58285c.