How to disable warning for "export item 'module ...' exports nothing"?

Isaac Dupree isaacdupree at
Thu Aug 14 13:31:34 EDT 2008

Sean Leather wrote:
> Hi,
> I have a module A that re-exports module B, and module B contains only class
> instances. Since I'm using -Wall, I get this warning about module B
> exporting nothing. Is there a way to disable this particular warning, since
> it is unnecessary in this case? No mailing list messages or GHC
> documentation has told me what to do.

Well, the warning is right that you don't need to re-export 
module B: instances are implicitly exported.  So you could 
just remove the export of "module B", unless there's a 
reason to export it (such as, you might add some exported 
functions or data types to it later)


More information about the Glasgow-haskell-users mailing list