Robustify the treatement of DFunUnfolding

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

diff --git a/compiler/typecheck/TcInstDcls.lhs b/compiler/typecheck/TcInstDcls.lhs
index 6ffa9d9..374fb6d 100644 (file)
--- a/compiler/typecheck/TcInstDcls.lhs
+++ b/compiler/typecheck/TcInstDcls.lhs
@@ -21,7 +21,6 @@ import FamInst
 import FamInstEnv
 import TcDeriv
 import TcEnv
-import RnEnv   ( lookupGlobalOccRn )
 import RnSource ( addTcgDUs )
 import TcHsType
 import TcUnify
@@ -33,6 +32,7 @@ import DataCon
 import Class
 import Var
 import CoreUnfold ( mkDFunUnfolding )
+import CoreSyn   ( Expr(Var) )
 import Id
 import MkId
 import Name
@@ -598,7 +598,7 @@ tc_inst_decl2 :: Id -> InstBindings Name -> TcM (LHsBinds Id)
 -- If there are no superclasses, matters are simpler, because we don't need the case
 -- see Note [Newtype deriving superclasses] in TcDeriv.lhs
 
-tc_inst_decl2 dfun_id (NewTypeDerived coi)
+tc_inst_decl2 dfun_id (NewTypeDerived coi _)
   = do  { let rigid_info = InstSkol
               origin     = SigOrigin rigid_info
               inst_ty    = idType dfun_id
@@ -705,9 +705,9 @@ tc_inst_decl2 dfun_id (NewTypeDerived coi)
 -- Ordinary instances
 
 tc_inst_decl2 dfun_id (VanillaInst monobinds uprags standalone_deriv)
-  = do { let rigid_info = InstSkol
-             inst_ty    = idType dfun_id
-             loc        = getSrcSpan dfun_id
+ = do { let rigid_info = InstSkol
+            inst_ty    = idType dfun_id
+            loc        = getSrcSpan dfun_id
 
         -- Instantiate the instance decl with skolem constants
        ; (inst_tyvars', dfun_theta', inst_head') <- tcSkolSigType rigid_info inst_ty
@@ -774,7 +774,8 @@ tc_inst_decl2 dfun_id (VanillaInst monobinds uprags standalone_deriv)
        ; let dict_constr   = classDataCon clas
              this_dict_id  = instToId this_dict
             dict_bind     = mkVarBind this_dict_id dict_rhs
-             dict_rhs      = foldl mk_app inst_constr (sc_ids ++ meth_ids)
+             dict_rhs      = foldl mk_app inst_constr sc_meth_ids
+             sc_meth_ids   = sc_ids ++ meth_ids
             inst_constr   = L loc $ wrapId (mkWpTyApps inst_tys')
                                            (dataConWrapId dict_constr)
                      -- We don't produce a binding for the dict_constr; instead we
@@ -792,7 +793,7 @@ tc_inst_decl2 dfun_id (VanillaInst monobinds uprags standalone_deriv)
                -- See Note [ClassOp/DFun selection]
                -- See also note [Single-method classes]
              dfun_id_w_fun = dfun_id  
-                             `setIdUnfolding`  mkDFunUnfolding dict_constr (sc_ids ++ meth_ids)
+                             `setIdUnfolding`  mkDFunUnfolding inst_ty (map Var sc_meth_ids)
                              `setInlinePragma` dfunInlinePragma
 
              main_bind = AbsBinds
@@ -1026,7 +1027,7 @@ tcInstanceMethod loc standalone_deriv clas tyvars dfun_dicts inst_tys
                 = do { meth_bind <- mkGenericDefMethBind clas inst_tys sel_id local_meth_name
                      ; tc_body meth_bind }
                  
-             tc_default DefMeth        -- An polymorphic default method
+             tc_default (DefMeth dm_name)      -- An polymorphic default method
                = do {   -- Build the typechecked version directly, 
                         -- without calling typecheck_method; 
                         -- see Note [Default methods in instances]
@@ -1034,8 +1035,7 @@ tcInstanceMethod loc standalone_deriv clas tyvars dfun_dicts inst_tys
                          --                      in $dm inst_tys this
                         -- The 'let' is necessary only because HsSyn doesn't allow
                         -- you to apply a function to a dictionary *expression*.
-                      dm_name <- lookupGlobalOccRn (mkDefMethRdrName sel_name)
-                                       -- Might not be imported, but will be an OrigName
+
                     ; dm_id <- tcLookupId dm_name
                      ; let dm_inline_prag = idInlinePragma dm_id
                            rhs = HsWrap (WpApp (instToId this_dict) <.> mkWpTyApps inst_tys) $