ekmett/linear — pull request #48 by polarina (2014-11-16 12:27:18+00:00)
Title: Add TypeFamilies extension to Linear.Matrix

This fixes one of several build errors when compiling with GHC HEAD.

src/Linear/Matrix.hs:65:4:
Illegal equational constraint Rep f ~ Rep f
(Use GADTs or TypeFamilies to permit this)
When checking that ‘o’ has the inferred type
o :: forall (f1 :: * -> *) (f2 :: * -> *).
(Representable f2, Representable f1, Rep f2 ~ Rep f,
Rep f1 ~ Rep f) =>
f2 b -> f1 t
In an equation for ‘column’:
column l f es
= o <$> f i
where
go = l (Context id)
i = tabulate $ \ e -> ipos $ go (index es e)
o eb = tabulate $ \ e -> ipeek (index eb e) (go (index es e))