X-Git-Url: http://git.megacz.com/?a=blobdiff_plain;f=compiler%2Ftypes%2FCoercion.lhs;h=35cf5a5a7b1cbe15ee84685ee67b04633e0925fa;hb=8b5bfdf4e780bae6c596825a1042b059f9ae4f2d;hp=ac2173c5c02604efd6bef899516facea09751e15;hpb=ad94d40948668032189ad22a0ad741ac1f645f50;p=ghc-hetmet.git

diff --git a/compiler/types/Coercion.lhs b/compiler/types/Coercion.lhs
index ac2173c..35cf5a5 100644
--- a/compiler/types/Coercion.lhs
+++ b/compiler/types/Coercion.lhs
@@ -16,7 +16,7 @@ The coercion kind constructor is a special TyCon that must always be saturated
 -- The above warning supression flag is a temporary kludge.
 -- While working on this module you are encouraged to remove it and fix
 -- any warnings in the module. See
---     http://hackage.haskell.org/trac/ghc/wiki/CodingStyle#Warnings
+--     http://hackage.haskell.org/trac/ghc/wiki/Commentary/CodingStyle#Warnings
 -- for details
 
 module Coercion (
@@ -371,7 +371,10 @@ transCoercionTyCon =
   where
     composeCoercionKindsOf (co1:co2:rest)
       = ASSERT( null rest )
-        WARN( not (r1 `coreEqType` a2), text "Strange! Type mismatch in trans coercion, probably a bug")
+        WARN( not (r1 `coreEqType` a2), 
+              text "Strange! Type mismatch in trans coercion, probably a bug"
+              $$
+              ppr r1 <+> text "=/=" <+> ppr a2)
         (a1, r2)
       where
         (a1, r1) = coercionKind co1
@@ -401,6 +404,9 @@ splitCoercionKindOf co
   , Just (ty_fun1, ty_arg1) <- splitAppTy_maybe ty1
   , Just (ty_fun2, ty_arg2) <- splitAppTy_maybe ty2
   = ((ty_fun1, ty_fun2),(ty_arg1, ty_arg2))
+splitCoercionKindOf co 
+  = pprPanic "Coercion.splitCoercionKindOf" 
+             (ppr co $$ ppr (coercionKindPredTy co))
 
 instCoercionTyCon 
   =  mkCoercionTyCon instCoercionTyConName 2 instCoercionKind