Add {-# OPTIONS_GHC -w #-} and some blurb to all compiler modules

[ghc-hetmet.git] / compiler / types / FamInstEnv.lhs

diff --git a/compiler/types/FamInstEnv.lhs b/compiler/types/FamInstEnv.lhs
index ee55583..8ac0453 100644 (file)
--- a/compiler/types/FamInstEnv.lhs
+++ b/compiler/types/FamInstEnv.lhs
@@ -5,6 +5,13 @@
 FamInstEnv: Type checked family instance declarations
 
 \begin{code}
+{-# OPTIONS_GHC -w #-}
+-- 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/WorkingConventions#Warnings
+-- for details
+
 module FamInstEnv (
        FamInst(..), famInstTyCon, famInstTyVars, 
        pprFamInst, pprFamInstHdr, pprFamInsts, 
@@ -277,7 +284,7 @@ indexed synonyms and we don't want to slow that down by needless unification.
 
 \begin{code}
 lookupFamInstEnvUnify :: (FamInstEnv, FamInstEnv) -> TyCon -> [Type]
-                     -> [(FamInstMatch)]
+                     -> [(FamInstMatch, TvSubst)]
 lookupFamInstEnvUnify (pkg_ie, home_ie) fam tys
   | not (isOpenTyCon fam) 
   = []
@@ -318,7 +325,7 @@ lookupFamInstEnvUnify (pkg_ie, home_ie) fam tys
         case tcUnifyTys bind_fn tpl_tys tys of
            Just subst -> let rep_tys = substTyVars subst (tyConTyVars tycon)
                           in
-                          (item, rep_tys) : find rest
+                          ((item, rep_tys), subst) : find rest
            Nothing    -> find rest
 
 -- See explanation at @InstEnv.bind_fn@.