On 7 June 2012 16:26, Simon Peyton-Jones wrote:

It's deliberate.

As the user manual says (http://www.haskell.org/ghc/docs/latest/html/users_guide/flag-reference.html#...), FlexibleInstances implies TypeSynonymInstances. See Trac http://hackage.haskell.org/trac/ghc/ticket/4841

I'll clarify the docs a bit.

That makes more sense now, thanks!

Simon

| -----Original Message----- | From: haskell-cafe-bounces@haskell.org [mailto:haskell-cafe- | bounces@haskell.org] 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 | 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 | > Ivan.Miljenovic@gmail.com | > http://IvanMiljenovic.wordpress.com | | | | -- | Ivan Lazar Miljenovic | Ivan.Miljenovic@gmail.com | http://IvanMiljenovic.wordpress.com | | _______________________________________________ | Haskell-Cafe mailing list | Haskell-Cafe@haskell.org | http://www.haskell.org/mailman/listinfo/haskell-cafe

-- Ivan Lazar Miljenovic Ivan.Miljenovic@gmail.com http://IvanMiljenovic.wordpress.com