Einar Wolfgang Karlsen writes:
> > odd instance decl - is this really the file that shows up the bug?
> >
>
> The file is the "correct" one - Yes. I played around with some of the
> ghc options. It seems as if it is -fglasgow-exts that is causing the
> problem. [...]
>
Thanks, -fglasgow-exts gives you the ability to define overlapping
instances, which is why it doesn't give you a typo, but, as it turns
out, a panic. (I suspect you prefer the former :-)
The misbehaviour is really due to the superfluous context used in the
instance decl
instance GUIValue a => GUIValue [[Char]] where { ... }
This should have been caught with a suitable warning/error msg.
Fixed in the next release.
--Sigbjorn
