[project @ 2000-10-24 07:35:00 by simonpj]

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

diff --git a/ghc/compiler/typecheck/TcInstDcls.lhs b/ghc/compiler/typecheck/TcInstDcls.lhs
index 73bbe59..245e762 100644 (file)
--- a/ghc/compiler/typecheck/TcInstDcls.lhs
+++ b/ghc/compiler/typecheck/TcInstDcls.lhs
@@ -56,8 +56,8 @@ import NameSet                ( emptyNameSet, nameSetToList )
 import PrelInfo                ( eRROR_ID )
 import PprType         ( pprConstraint, pprPred )
 import TyCon           ( TyCon, isSynTyCon, tyConDerivings )
-import Type            ( mkTyVarTys, splitSigmaTy, isTyVarTy,
-                         splitTyConApp_maybe, splitDictTy_maybe,
+import Type            ( mkTyVarTys, splitDFunTy, isTyVarTy,
+                         splitTyConApp_maybe, splitDictTy,
                          splitAlgTyConApp_maybe, classesToPreds, classesOfPreds,
                          unUsgTy, tyVarsOfTypes, mkClassPred, mkTyVarTy,
                          getClassTys_maybe
@@ -247,10 +247,7 @@ tcInstDecl1 mod unf_env (InstDecl poly_ty binds uprags maybe_dfun_name src_loc)
        -- Type-check all the stuff before the "where"
     tcHsSigType poly_ty                        `thenTc` \ poly_ty' ->
     let
-       (tyvars, theta, dict_ty) = splitSigmaTy poly_ty'
-       (clas, inst_tys)         = case splitDictTy_maybe dict_ty of
-                                    Just ct -> ct
-                                    Nothing -> pprPanic "tcInstDecl1" (ppr poly_ty)
+       (tyvars, theta, clas, inst_tys) = splitDFunTy poly_ty'
     in
 
     (case maybe_dfun_name of
@@ -324,7 +321,7 @@ getGenericInstances mod class_decls
     returnTc gen_inst_info
 
 get_generics mod decl@(ClassDecl context class_name tyvar_names 
-                                fundeps class_sigs def_methods pragmas 
+                                fundeps class_sigs def_methods
                                 name_list loc)
   | null groups                
   = returnTc [] -- The comon case: 
@@ -521,7 +518,7 @@ tcInstDecl2 (InstInfo { iClass = clas, iTyVars = inst_tyvars, iTys = inst_tys,
        -- Instantiate the instance decl with tc-style type variables
     tcInstId dfun_id           `thenNF_Tc` \ (inst_tyvars', dfun_theta', dict_ty') ->
     let
-       (clas, inst_tys') = expectJust "tcInstDecl2" (splitDictTy_maybe dict_ty')
+       (clas, inst_tys') = splitDictTy dict_ty'
        origin            = InstanceDeclOrigin
 
         (class_tyvars, sc_theta, _, op_items) = classBigSig clas
@@ -777,10 +774,10 @@ tcAddDeclCtxt decl thing_inside
   where
      (name, loc, thing)
        = case decl of
-           (ClassDecl _ name _ _ _ _ _ _ loc)         -> (name, loc, "class")
-           (TySynonym name _ _ loc)                   -> (name, loc, "type synonym")
-           (TyData NewType  _ name _ _ _ _ _ loc _ _) -> (name, loc, "newtype")
-           (TyData DataType _ name _ _ _ _ _ loc _ _) -> (name, loc, "data type")
+           (ClassDecl _ name _ _ _ _ _ loc)         -> (name, loc, "class")
+           (TySynonym name _ _ loc)                 -> (name, loc, "type synonym")
+           (TyData NewType  _ name _ _ _ _ loc _ _) -> (name, loc, "newtype")
+           (TyData DataType _ name _ _ _ _ loc _ _) -> (name, loc, "data type")
 
      ctxt = hsep [ptext SLIT("In the"), text thing, 
                  ptext SLIT("declaration for"), quotes (ppr name)]