[project @ 2000-11-07 15:21:38 by simonmar]

[ghc-hetmet.git] / ghc / compiler / typecheck / TcInstDcls.lhs

diff --git a/ghc/compiler/typecheck/TcInstDcls.lhs b/ghc/compiler/typecheck/TcInstDcls.lhs
index 54967ac..ca18b67 100644 (file)
--- a/ghc/compiler/typecheck/TcInstDcls.lhs
+++ b/ghc/compiler/typecheck/TcInstDcls.lhs
@@ -57,7 +57,7 @@ import TyCon          ( TyCon, isSynTyCon )
 import Type            ( splitDFunTy, isTyVarTy,
                          splitTyConApp_maybe, splitDictTy,
                          splitAlgTyConApp_maybe, splitForAllTys,
-                         unUsgTy, tyVarsOfTypes, mkClassPred, mkTyVarTy,
+                         tyVarsOfTypes, mkClassPred, mkTyVarTy,
                          getClassTys_maybe
                        )
 import Subst           ( mkTopTyVarSubst, substClasses )
@@ -369,9 +369,11 @@ getGenericBinds (AndMonoBinds m1 m2)
   = plusAssoc_C AndMonoBinds (getGenericBinds m1) (getGenericBinds m2)
 
 getGenericBinds (FunMonoBind id infixop matches loc)
-  = mapAssoc wrap (foldr add emptyAssoc matches)
+  = mapAssoc wrap (foldl add emptyAssoc matches)
+       -- Using foldl not foldr is vital, else
+       -- we reverse the order of the bindings!
   where
-    add match env = case maybeGenericMatch match of
+    add env match = case maybeGenericMatch match of
                      Nothing           -> env
                      Just (ty, match') -> extendAssoc_C (++) env (ty, [match'])
 
@@ -613,7 +615,7 @@ tcInstDecl2 (InstInfo { iLocal = is_local, iDFunId = dfun_id,
                -- emit an error message.  This in turn means that we don't
                -- mention the constructor, which doesn't exist for CCallable, CReturnable
                -- Hardly beautiful, but only three extra lines.
-           HsApp (TyApp (HsVar eRROR_ID) [(unUsgTy . idType) this_dict_id])
+           HsApp (TyApp (HsVar eRROR_ID) [idType this_dict_id])
                  (HsLit (HsString msg))
 
          | otherwise   -- The common case