Hiding non-existent entities

Manuel M. T. Chakravarty chak@cse.unsw.edu.au
Thu, 30 Aug 2001 16:20:14 +1000

"Simon Marlow" <simonmar@microsoft.com> wrote,

> The Haskell 98 errata page currently contains this item related to a
> hiding clause on an import declaration which refers to a non-existent
> entity:
>   [Aug 2001] Page 66, Section 5.3, Import Declarations,
>   numbered item 2. Add "It is not an error to hide an entity
>   that is not, in fact, exported by the imported module, although
>   compilers are encouraged to flag a warning in this case." (This
>   is different from what I proposed by email, which made this case
>   an error, but it allow a bit more flexibility as modules change.)
> IMO allowing a hiding clause to refer to a non-existent entity is a bit
> odd.  Haskell doesn't have any other features like this: it's always an
> error to refer to an entity that isn't defined anywhere, even if the
> reference is otherwise harmless.  Does anyone else have any opinions on
> this?

I agree with you.