It's deliberate. As the user manual says (http://www.haskell.org/ghc/docs/latest/html/users_guide/flag-reference.html#id3101511), FlexibleInstances implies TypeSynonymInstances. See Trac http://hackage.haskell.org/trac/ghc/ticket/4841
I'll clarify the docs a bit. Simon | -----Original Message----- | From: [email protected] [mailto:haskell-cafe- | [email protected]] On Behalf Of Ivan Lazar Miljenovic | Sent: 06 June 2012 23:34 | To: Haskell Cafe | Subject: Re: [Haskell-cafe] GHC 7.4 and TypeSynonymInstances | | *Bump* | | Especially as there is now a version of the Haskell Platform based | around GHC-7.4.1, I would appreciate it if this behaviour could be | clarified. | | On 20 April 2012 15:25, Ivan Lazar Miljenovic | <[email protected]> wrote: | > Has there been a change in the behaviour/requirement of | > TypeSynonymInstances as of GHC-7.4.1? (Not sure if this behaviour | > occurs with 7.2.1 as I don't have it installed) | > | > I had an instance for String for a class which ghc accepted whilst | > using FlexibleInstances; however, when trying to load it in 7.0.* it | > stated that TypeSynonymInstances was needed (which I forgot to add | > since it didn't seem to need it). | > | > All I could find in the release notes was that as of 7.2.1, both | > extensions were needed, not that one implied the other: | > http://www.haskell.org/ghc/docs/7.4.1/html/users_guide/release-7-2-1.h | > tml#id3003826 | > | > Is this behaviour deliberate, or a bug? | > | > -- | > Ivan Lazar Miljenovic | > [email protected] | > http://IvanMiljenovic.wordpress.com | | | | -- | Ivan Lazar Miljenovic | [email protected] | http://IvanMiljenovic.wordpress.com | | _______________________________________________ | Haskell-Cafe mailing list | [email protected] | http://www.haskell.org/mailman/listinfo/haskell-cafe _______________________________________________ Haskell-Cafe mailing list [email protected] http://www.haskell.org/mailman/listinfo/haskell-cafe
