Warning: Unknown extensions: ViewPatterns

Duncan Coutts duncan.coutts at worc.ox.ac.uk
Mon Dec 22 06:23:30 EST 2008

On Mon, 2008-12-22 at 09:55 +0000, Neil Mitchell wrote:
> Hi
> It appears cabal doesn't know ViewPatterns are a valid extension:

Sun Oct 19 15:14:08 BST 2008  Ian Lynagh <igloo at earth.li>
  * Add GHC 6.10.1's extensions to the list in

This patch was added after the release (which came with
ghc-6.10.1). It'll be in

> hlint$ cabal install --global
> Resolving dependencies...
> Configuring hlint-
> Warning: Unknown extensions: ViewPatterns
> Preprocessing executables for hlint-
> Building hlint-
> Thanks

Note that it worked despite the extension being unknown. Using
unregistered extensions works so long as the compiler supports them. The
only thing that we prevent is uploading packages that are using
unregistered extensions.


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