On Fri, Oct 10, 2008 at 8:40 PM, Niklas Broberg
src\HSX\XMLGenerator.hs:71:0 Illegal type synonym family application in instance: XML m In the instance declaration for `EmbedAsChild m (XML m)ยด ---------------
Could someone help me point out the problem here? The relevant code is:
instance XMLGen m => EmbedAsChild m (XML m) where asChild = return . return . xmlToChild
class XMLGen m => EmbedAsChild m c where asChild :: c -> GenChildList m
class Monad m => XMLGen m where type XML m ....
This works fine with 6.8.3, so what's new in 6.10, and what would I do to solve it?
I'm guessing there was a bug in 6.8.3 that allowed this. (The
implementation of type families is present but not supported in 6.8,
presumably because of problems like this.)
I don't have 6.10, so I can't test anything, but you might try
rewriting the EmbedAsChild instances like so:
instance (XMLGen m, XML m ~ x) => EmbedAsChild m x where ...
Alternatively, you can make separate instances for every type in the
range of XML.
--
Dave Menendez