[commit: ghc] master: Allow deriving Typeable for more tycons (92191a3)

[José Pedro Magalhães]

Repository : http://darcs.haskell.org/ghc.git/

On branch  : master

https://github.com/ghc/ghc/commit/92191a39a59a036fde4de926e2e322a2c50c84cf

>---------------------------------------------------------------

commit 92191a39a59a036fde4de926e2e322a2c50c84cf
Author: Jose Pedro Magalhaes <jpm at cs.ox.ac.uk>
Date:   Tue May 7 09:16:29 2013 +0100

    Allow deriving Typeable for more tycons

>---------------------------------------------------------------

 compiler/typecheck/TcDeriv.lhs | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/compiler/typecheck/TcDeriv.lhs b/compiler/typecheck/TcDeriv.lhs
index 7da30d19b..9b82ed6 100644
--- a/compiler/typecheck/TcDeriv.lhs
+++ b/compiler/typecheck/TcDeriv.lhs
@@ -683,7 +683,8 @@ mkEqnHelp :: CtOrigin -> [TyVar] -> Class -> [Type] -> Type
 
 mkEqnHelp orig tvs cls cls_tys tc_app mtheta
   | Just (tycon, tc_args) <- tcSplitTyConApp_maybe tc_app
-  , isAlgTyCon tycon    -- Check for functions, primitive types etc
+  , className cls == typeableClassName || isAlgTyCon tycon
+  -- Avoid functions, primitive types, etc, unless it's Typeable
   = mk_alg_eqn tycon tc_args
   | otherwise
   = failWithTc (derivingThingErr False cls cls_tys tc_app