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| author | Simon Peyton Jones <simonpj@microsoft.com> | 2017-02-21 13:29:16 +0000 |
|---|---|---|
| committer | Simon Peyton Jones <simonpj@microsoft.com> | 2017-02-21 14:26:57 +0000 |
| commit | 713ebd7cf03876c6bedc1be9fba8f60ccc5bc8f0 (patch) | |
| tree | 8aa42a785d1ea8ee84b69ca091c09ac4ef8d6aba /compiler/typecheck/TcDeriv.hs | |
| parent | fd841f877ab7a991f667a50b401404927f6f599c (diff) | |
| download | haskell-713ebd7cf03876c6bedc1be9fba8f60ccc5bc8f0.tar.gz | |
Fix computation of dfun_tvs in mkNewTypeEqn
This bug was causing Trac #13297.
We were recomputing ds_tvs, and doing it wrongly (by omitting
variables that appear only in mtheta). But actually plain 'tvs'
is just fine. So code deleted, and bug fixed.
Diffstat (limited to 'compiler/typecheck/TcDeriv.hs')
| -rw-r--r-- | compiler/typecheck/TcDeriv.hs | 7 |
1 files changed, 3 insertions, 4 deletions
diff --git a/compiler/typecheck/TcDeriv.hs b/compiler/typecheck/TcDeriv.hs index 00869c4f4b..55b7d6d64f 100644 --- a/compiler/typecheck/TcDeriv.hs +++ b/compiler/typecheck/TcDeriv.hs @@ -1177,7 +1177,7 @@ mkNewTypeEqn dflags overlap_mode tvs case mtheta of Just theta -> return $ GivenTheta $ DS { ds_loc = loc - , ds_name = dfun_name, ds_tvs = dfun_tvs + , ds_name = dfun_name, ds_tvs = tvs , ds_cls = cls, ds_tys = inst_tys , ds_tc = rep_tycon , ds_theta = theta @@ -1185,7 +1185,7 @@ mkNewTypeEqn dflags overlap_mode tvs , ds_mechanism = mechanism } Nothing -> return $ InferTheta $ DS { ds_loc = loc - , ds_name = dfun_name, ds_tvs = dfun_tvs + , ds_name = dfun_name, ds_tvs = tvs , ds_cls = cls, ds_tys = inst_tys , ds_tc = rep_tycon , ds_theta = all_thetas @@ -1258,7 +1258,6 @@ mkNewTypeEqn dflags overlap_mode tvs -- See Note [Newtype deriving superclasses] above sc_preds :: [PredOrigin] cls_tyvars = classTyVars cls - dfun_tvs = tyCoVarsOfTypesWellScoped inst_tys inst_ty = mkTyConApp tycon tc_args inst_tys = cls_tys ++ [inst_ty] sc_preds = map (mkPredOrigin DerivOrigin TypeLevel) $ @@ -1278,7 +1277,7 @@ mkNewTypeEqn dflags overlap_mode tvs = [ mkPredOrigin (DerivOriginCoerce meth t1 t2) TypeLevel (mkReprPrimEqPred t1 t2) | meth <- meths - , let (Pair t1 t2) = mkCoerceClassMethEqn cls dfun_tvs + , let (Pair t1 t2) = mkCoerceClassMethEqn cls tvs inst_tys rep_inst_ty meth ] all_thetas :: [ThetaOrigin] |