[Haskell-cafe] module export question

[Luke Palmer]

On Tue, Dec 1, 2009 at 3:11 PM, Sean McLaughlin <seanmcl at gmail.com> wrote:
> Say I have the following module:
>
> ----------------------------------------
> module A
>  ( T(T)
>  , t
>  , val
>  )
> where
>
> data T = T { t :: Int }
>
> val :: T
> val = T 7
> ----------------------------------------
>
>
> When I use A with the following imports, I don't expect this to work,
> but it does:
>
> import qualified A
> import A(T(..))
>
> main = putStrLn $ show $ t A.val
>
> The problem is that I explicitly didn't export 't' as an element of T
> (by not writing T(..)).
> Am I just misunderstanding how exports work?  I couldn't figure out
> what the correct
> behavior should be by looking at the 98 report.

Oh interesting.  What a crazy corner case.  I also feel like your
program shouldn't be valid.  Maybe it's a bug?