Hello all,<br><br>This email is to draw your attention to <a href="http://hackage.haskell.org/trac/ghc/ticket/7256">http://hackage.haskell.org/trac/ghc/ticket/7256</a>. Missing dataCast1 and dataCast2 methods in Data instances results in incorrect behaviour when using SYB's ext1/ext2 functions. The proposed fix adds the methods, but it requires adding additional Data constraints to these instances. Here's the relevant part of the diff:<br>
<br><blockquote style="margin:0px 0px 0px 0.8ex;border-left:1px solid rgb(204,204,204);padding-left:1ex" class="gmail_quote"><span style="font-family:courier new,monospace">-instance Typeable a => Data (Ptr a) where<br>
+instance (Data a, Typeable a) => Data (Ptr a) where<br> <br>-instance Typeable a => Data (ForeignPtr a) where<br>+instance (Data a, Typeable a) => Data (ForeignPtr a) where<br><br>-instance (Typeable a, Data b, Ix a) => Data (Array a b)<br>
+instance (Typeable a, Data a, Data b, Ix a) => Data (Array a b)<br></span></blockquote><br>Does anyone find this change problematic?<br><br><br>Cheers,<br>Pedro<br><br>