Use implication constraints to improve type inference

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

diff --git a/compiler/typecheck/TcClassDcl.lhs b/compiler/typecheck/TcClassDcl.lhs
index 30dfc7c..92c7958 100644 (file)
--- a/compiler/typecheck/TcClassDcl.lhs
+++ b/compiler/typecheck/TcClassDcl.lhs
@@ -271,7 +271,7 @@ tcDefMeth origin clas tyvars binds_in sig_fn prag_fn sel_id
     
         -- Check the context
        { dict_binds <- tcSimplifyCheck
-                               (ptext SLIT("class") <+> ppr clas)
+                               loc
                                tyvars
                                [this_dict]
                                insts_needed
@@ -362,18 +362,18 @@ tcMethodBind inst_tyvars inst_theta avail_insts sig_fn prag_fn
 
     let
        [(_, Just sig, local_meth_id)] = mono_bind_infos
+       loc = sig_loc sig
     in
 
     addErrCtxtM (sigCtxt sel_id inst_tyvars inst_theta (idType meth_id))       $
-    newDictBndrs (sig_loc sig) (sig_theta sig)         `thenM` \ meth_dicts ->
+    newDictBndrs loc (sig_theta sig)           `thenM` \ meth_dicts ->
     let
        meth_tvs   = sig_tvs sig
        all_tyvars = meth_tvs ++ inst_tyvars
        all_insts  = avail_insts ++ meth_dicts
     in
     tcSimplifyCheck
-        (ptext SLIT("class or instance method") <+> quotes (ppr sel_id))
-        all_tyvars all_insts meth_lie          `thenM` \ lie_binds ->
+        loc all_tyvars all_insts meth_lie      `thenM` \ lie_binds ->
 
     checkSigTyVars all_tyvars                  `thenM_`
 
@@ -537,8 +537,8 @@ mkDefMethRhs origin clas inst_tys sel_id loc GenDefMeth
                                  other                                           -> Nothing
                        other -> Nothing
 
-isInstDecl (SigOrigin (InstSkol _)) = True
-isInstDecl (SigOrigin (ClsSkol _))  = False
+isInstDecl (SigOrigin InstSkol)    = True
+isInstDecl (SigOrigin (ClsSkol _)) = False
 \end{code}