[project @ 2001-10-25 02:13:10 by sof]

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

diff --git a/ghc/compiler/typecheck/TcIfaceSig.lhs b/ghc/compiler/typecheck/TcIfaceSig.lhs
index cc7d9b6..b559686 100644 (file)
--- a/ghc/compiler/typecheck/TcIfaceSig.lhs
+++ b/ghc/compiler/typecheck/TcIfaceSig.lhs
@@ -37,7 +37,7 @@ import Var            ( mkTyVar, tyVarKind )
 import Name            ( Name, nameIsLocalOrFrom )
 import ErrUtils                ( pprBagOfErrors )
 import Outputable      
-import Util            ( zipWithEqual )
+import Util            ( zipWithEqual, dropList, equalLength )
 import HscTypes                ( TyThing(..) )
 \end{code}
 
@@ -337,10 +337,10 @@ tcCoreAlt scrut_ty alt@(con, names, rhs)
        ex_tyvars'          = [mkTyVar name (tyVarKind tv) | (name,tv) <- names `zip` ex_tyvars] 
        ex_tys'             = mkTyVarTys ex_tyvars'
        arg_tys             = dataConArgTys con (inst_tys ++ ex_tys')
-       id_names            = drop (length ex_tyvars) names
+       id_names            = dropList ex_tyvars names
        arg_ids
 #ifdef DEBUG
-               | length id_names /= length arg_tys
+               | not (equalLength id_names arg_tys)
                = pprPanic "tcCoreAlts" (ppr (con, names, rhs) $$
                                         (ppr main_tyvars <+> ppr ex_tyvars) $$
                                         ppr arg_tys)
@@ -348,7 +348,7 @@ tcCoreAlt scrut_ty alt@(con, names, rhs)
 #endif
                = zipWithEqual "tcCoreAlts" mkLocalId id_names arg_tys
     in
-    ASSERT( con `elem` tyConDataCons tycon && length inst_tys == length main_tyvars )
+    ASSERT( con `elem` tyConDataCons tycon && equalLength inst_tys main_tyvars )
     tcExtendTyVarEnv ex_tyvars'                        $
     tcExtendGlobalValEnv arg_ids               $
     tcCoreExpr rhs                                     `thenTc` \ rhs' ->