Re: [Haskell-cafe] Module visibility of data type constructors

On Sat, Nov 04, 2006 at 09:39:39PM +0200, Slavomir Kaslev wrote:

To: haskell-cafe@haskell.org From: Slavomir Kaslev Date: Sat, 4 Nov 2006 21:39:39 +0200 Subject: [Haskell-cafe] Module visibility of data type constructors

Hello. I have a simple question for data type constructors visibility. Take a look:

module Foo (Bar) where data Bar = Bar

In ghc this allows me to use Bar, the type constructor, in another module, although it shouldn't be visible outside Foo. On the other hand, if I change Bar's definition as:

data Bar = Baz

Baz isn't visible outside Foo.

Is this the correct behavior or is it bug in ghc?

It's not the correct behavior. The question is whether the bug is in your code or in ghc (with me it's usually the former :-). I can't reproduce this with my ghc 6.4. Which version are you using? Can you post the other module you are talking about? matthias