-Wall -Werror

[Ashley Yakeley]

Simon Peyton-Jones wrote:
> | Patch pushed. I've plumped for option a. It's better structuring, as b
> | would involve moving more code from Gregorian.hs to Days.hs.
> |
> | The concern Henning raised shouldn't apply, as both modules are hidden
> | and re-exported by Data.Time.Calendar. I've also fixed two other modules
> | with the same issue (again, also hidden).
> 
> Thanks.  It doesn't matter whether they are hidden or not --- their instances are visible regardless in Haskell.  So those interface files will be read any time you compile a module that depends on a module in the time package.  But that's not a terribly big deal.

What I meant was, the module in which the instance is defined, and the 
module in which the type is defined are both hidden, and only 
re-exported by another module. Thus it is not possible to import the 
type without importing the instance. I believe this is the concern that 
Henning Thielemann raised.

-- 
Ashley Yakeley