[project @ 2002-11-18 14:25:50 by simonpj]

[ghc-hetmet.git] / ghc / compiler / main / MkIface.lhs

diff --git a/ghc/compiler/main/MkIface.lhs b/ghc/compiler/main/MkIface.lhs
index b4178db..5025473 100644 (file)
--- a/ghc/compiler/main/MkIface.lhs
+++ b/ghc/compiler/main/MkIface.lhs
@@ -55,7 +55,7 @@ import TyCon          ( DataConDetails(..), tyConTyVars, tyConDataCons, tyConTheta,
                          getSynTyConDefn, tyConGenInfo, tyConDataConDetails, tyConArity )
 import Class           ( classExtraBigSig, classTyCon, DefMeth(..) )
 import FieldLabel      ( fieldLabelType )
-import TcType          ( tcSplitSigmaTy, tidyTopType, deNoteType, tyClsNamesOfDFunHead )
+import TcType          ( tcSplitForAllTys, tcFunResultTy, tidyTopType, deNoteType, tyClsNamesOfDFunHead )
 import SrcLoc          ( noSrcLoc )
 import Module          ( Module, ModuleName, moduleNameFS, moduleName, isHomeModule,
                          ModLocation(..), mkSysModuleNameFS, 
@@ -248,7 +248,13 @@ ifaceTyThing (AClass clas) = cls_decl
        = ASSERT(sel_tyvars == clas_tyvars)
          ClassOpSig (getName sel_id) def_meth' (toHsType op_ty) noSrcLoc
        where
-         (sel_tyvars, _, op_ty) = tcSplitSigmaTy (idType sel_id)
+               -- Be careful when splitting the type, because of things
+               -- like         class Foo a where
+               --                op :: (?x :: String) => a -> a
+               -- and          class Baz a where
+               --                op :: (Ord a) => a -> a
+         (sel_tyvars, rho_ty) = tcSplitForAllTys (idType sel_id)
+         op_ty                = tcFunResultTy rho_ty
          def_meth' = case def_meth of
                         NoDefMeth  -> NoDefMeth
                         GenDefMeth -> GenDefMeth