On Tue, Jan 3, 2012 at 6:44 PM, Brandon Allbery <allbery.b@gmail.com> wrote:
> On Tue, Jan 3, 2012 at 05:17, Yucheng Zhang <yczhang89@gmail.com> wrote:
>>
>> subsome :: [RRule nt t s] -> Either String ([t], s)
>>
>> It seems to me that the compiler is not sure the two 'nt' are equal.
>> The ScopedTypeVariables can make the compiler believe they are equal.
>
> But ScopedTypeVariables is enabled already.

Sorry, I meant actually using ScopedTypeVariables as in the first function,
which compiles well:

legSome :: LegGram nt t s -> nt -> Either String ([t], s)