[project @ 2004-10-11 16:16:20 by simonpj]

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

diff --git a/ghc/compiler/typecheck/TcPat.lhs b/ghc/compiler/typecheck/TcPat.lhs
index 2f583bb..625bd12 100644 (file)
--- a/ghc/compiler/typecheck/TcPat.lhs
+++ b/ghc/compiler/typecheck/TcPat.lhs
@@ -385,15 +385,18 @@ tcConPat ctxt data_con tycon ty_args arg_pats thing_inside
              arg_tys' = substTys tenv arg_tys
              res_tys' = substTys tenv res_tys
        ; dicts <- newDicts (SigOrigin rigid_info) theta'
-       ; tcInstStupidTheta data_con tv_tys'
 
        -- Do type refinement!
        ; traceTc (text "tcGadtPat" <+> vcat [ppr data_con, ppr tvs', ppr arg_tys', ppr res_tys', 
                                              text "ty-args:" <+> ppr ty_args ])
        ; refineAlt ctxt data_con tvs' ty_args res_tys' $ do    
 
-       { ((arg_pats', inner_tvs, res), lie_req) 
-               <- getLIE (tcConArgs ctxt data_con arg_pats arg_tys' thing_inside)
+       { ((arg_pats', inner_tvs, res), lie_req) <- getLIE $
+               do { tcInstStupidTheta data_con tv_tys'
+                       -- The stupid-theta mentions the newly-bound tyvars, so
+                       -- it must live inside the getLIE, so that the
+                       --  tcSimplifyCheck will apply the type refinement to it
+                  ; tcConArgs ctxt data_con arg_pats arg_tys' thing_inside }
 
        ; dict_binds <- tcSimplifyCheck doc tvs' dicts lie_req