Re: [Haskell-cafe] zlib build failure on recent GHC

On Monday 07 November 2011, 21:06:17, Jason Dagit wrote:

On Mon, Nov 7, 2011 at 8:17 AM, Johan Tibell wrote:

...

This is due to a change in how FFI imports and newtypes work. GHC was recently changed to not allow you to use newtypes in FFI imports unless the constructor of the newtype is in scope. This broke quite a few libraries. I have patched a few of them and I've sent a patch to the zlib maintainer.

This seems like a big change.

But it introduces conformance with the report: http://www.haskell.org/onlinereport/haskell2010/haskellch8.html#x15-1540008.... (sec. 8.4.2, Foreign Types) "Consequently, in order for a type defined by newtype to be used in a foreign declaration outside of the module that defines it, the type must not be exported abstractly." Previous behaviour violated that, hence the change.

Where should I be watching to know about this ahead of time? I bet I have to fix some of my packages.

Thanks, Jason