I've just found http://hackage.haskell.org/trac/ghc/ticket/5377 which explains it. C. Am 05.08.2011 12:56, schrieb Christian Maeder:
Hi,
I've noticed that with ghc-7.2 many modules with LANGUAGE TypeSynonymInstances now also require FlexibleInstances
Two examples are in the HTTP package Network.TCP and Network.BufferType
Was ghc-7.0 wrong about this, before?
Cheers Christian
Am 29.07.2011 20:21, schrieb Ian Lynagh:
We are pleased to announce the first release candidate for GHC 7.2.1:
http://www.haskell.org/ghc/dist/7.2.1-rc1/
This includes the source and testsuite tarballs, installers for OS X and Windows, and bindists for amd64/Linux, i386/Linux, amd64/FreeBSD and i386/FreeBSD.
Please test as much as possible; bugs are much cheaper if we find them before the release!
Thanks Ian, on behalf of the GHC team