proposal #2254: have Control.Arrow re-export (>>>) and (<<<)
ross at soi.city.ac.uk
Fri May 2 04:10:24 EDT 2008
On Fri, May 02, 2008 at 08:30:03AM +0100, Simon Peyton-Jones wrote:
> | Generally, if module A exports foo, module B imports A and re-exports
> | foo, and module C imports both A and B, there should be no ambiguity.
> | Not even if it reexports all of modules A and B. Why would e.g. GHC
> | need to warn in that case?
> Perhaps Niklas can say whether #1148 is the bug he is describing, and if not file a new one?
module A where
foo x = x
module B(foo) where
module C where
c = foo 'a'
ghc -W says
Warning: Module `A' is imported, but nothing from it is used,
except perhaps instances visible in `A'
To suppress this warning, use: import A()
It's true that the import can be deleted, but not that "nothing from it
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