[project @ 1999-12-01 12:02:48 by sewardj]

Disable the Mark Jones optimisation for instance decls, since it is
incompatible with Hugs.

diff --git a/ghc/compiler/basicTypes/MkId.lhs b/ghc/compiler/basicTypes/MkId.lhs
index 158cc3d..878868f 100644 (file)
--- a/ghc/compiler/basicTypes/MkId.lhs
+++ b/ghc/compiler/basicTypes/MkId.lhs
@@ -453,6 +453,11 @@ mkDictFunId dfun_name clas inst_tyvars inst_tys inst_decl_theta
     (class_tyvars, sc_theta, _, _) = classBigSig clas
     sc_theta' = substTheta (mkTopTyVarSubst class_tyvars inst_tys) sc_theta
 
+    dfun_theta = inst_decl_theta
+
+{-  1 dec 99: disable the Mark Jones optimisation for the sake
+    of compatibility with Hugs.
+
     dfun_theta = case inst_decl_theta of
                   []    -> []  -- If inst_decl_theta is empty, then we don't
                                -- want to have any dict arguments, so that we can
@@ -472,7 +477,7 @@ mkDictFunId dfun_name clas inst_tyvars inst_tys inst_decl_theta
                                --   class Foo a => Baz a b where ...
                                --   instance Wob b => Baz T b where..
                                -- Now sc_theta' has Foo T
-
+-}
     dfun_ty = mkSigmaTy inst_tyvars dfun_theta (mkDictTy clas inst_tys)
 
     not_const (clas, tys) = not (isEmptyVarSet (tyVarsOfTypes tys))