[project @ 2001-11-23 12:06:49 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 b992ce1..6578580 100644 (file)
--- a/ghc/compiler/typecheck/TcInstDcls.lhs
+++ b/ghc/compiler/typecheck/TcInstDcls.lhs
@@ -23,10 +23,11 @@ import TcHsSyn              ( TcMonoBinds, mkHsConApp )
 import TcBinds         ( tcSpecSigs )
 import TcClassDcl      ( tcMethodBind, badMethodErr )
 import TcMonad       
-import TcMType         ( tcInstTyVars, checkValidTheta, checkValidInstHead, instTypeErr,
+import TcMType         ( tcInstSigTyVars, checkValidTheta, checkValidInstHead, instTypeErr, 
                          UserTypeCtxt(..), SourceTyCtxt(..) )
-import TcType          ( tcSplitDFunTy, mkClassPred, mkTyVarTy,
-                         tcSplitSigmaTy, tcSplitPredTy_maybe, getClassPredTys
+import TcType          ( tcSplitDFunTy, mkClassPred, mkTyVarTy, mkTyVarTys,
+                         tcSplitSigmaTy, tcSplitPredTy_maybe, getClassPredTys,
+                         TyVarDetails(..)
                        )
 import Inst            ( InstOrigin(..),
                          newDicts, instToId,
@@ -524,15 +525,15 @@ tcInstDecl2 (InstInfo { iDFunId = dfun_id,
     let
        (inst_tyvars, dfun_theta, clas, inst_tys) = tcSplitDFunTy (idType dfun_id)
     in
-    tcInstTyVars inst_tyvars           `thenNF_Tc` \ (inst_tyvars', _, tenv) ->
+    tcInstSigTyVars InstTv inst_tyvars         `thenNF_Tc` \ inst_tyvars' ->
     let
+       tenv        = mkTopTyVarSubst inst_tyvars (mkTyVarTys inst_tyvars')
        inst_tys'   = map (substTy tenv) inst_tys
        dfun_theta' = substTheta tenv dfun_theta
        origin      = InstanceDeclOrigin
 
         (class_tyvars, sc_theta, _, op_items) = classBigSig clas
 
-       dm_ids    = [dm_id | (_, DefMeth dm_id) <- op_items]
        sel_names = [idName sel_id | (sel_id, _) <- op_items]
 
         -- Instantiate the super-class context with inst_tys
@@ -553,14 +554,15 @@ tcInstDecl2 (InstInfo { iDFunId = dfun_id,
        -- The type variable from the dict fun actually scope 
        -- over the bindings.  They were gotten from
        -- the original instance declaration
-       tcExtendGlobalValEnv dm_ids (
-               -- Default-method Ids may be mentioned in synthesised RHSs 
+
+               -- Default-method Ids may be mentioned in synthesised RHSs,
+               -- but they'll already be in the environment.
 
        mapAndUnzip3Tc (tcMethodBind clas origin inst_tyvars' inst_tys'
                                     dfun_theta'
                                     monobinds uprags True)
                       op_items
-    ))                 `thenTc` \ (method_binds_s, insts_needed_s, meth_insts) ->
+    )                  `thenTc` \ (method_binds_s, insts_needed_s, meth_insts) ->
 
        -- Deal with SPECIALISE instance pragmas by making them
        -- look like SPECIALISE pragmas for the dfun