; insts2 <- mapM (genInst False overlap_flag) final_specs
- -- Generate the (old) generic to/from functions from each type declaration
+ -- We no longer generate the old generic to/from functions
+ -- from each type declaration, so this is emptyBag
; gen_binds <- return emptyBag -- mkGenericBinds is_boot tycl_decls
- -- Generate the generic Representable0/1 instances from each type declaration
- ; repInstsMeta <- genGenericRepBinds is_boot tycl_decls
+ -- Generate the generic Representable0 instances
+ -- from each type declaration
+ ; repInstsMeta <- genGenericRepBinds is_boot tycl_decls
; let repInsts = concat (map (\(a,_,_) -> a) repInstsMeta)
repMetaTys = map (\(_,b,_) -> b) repInstsMeta
repTyCons = map (\(_,_,c) -> c) repInstsMeta
- -- Should we extendLocalInstEnv with repInsts?
- ; (inst_info, rn_binds, rn_dus) <- renameDeriv is_boot gen_binds (insts1 ++ insts2 ++ repInsts)
+ ; (inst_info, rn_binds, rn_dus)
+ <- renameDeriv is_boot gen_binds (insts1 ++ insts2 ++ repInsts)
; dflags <- getDOpts
; liftIO (dumpIfSet_dyn dflags Opt_D_dump_deriv "Derived instances"
gen_soln (DS { ds_loc = loc, ds_orig = orig, ds_tvs = tyvars
, ds_cls = clas, ds_tys = inst_tys, ds_theta = deriv_rhs })
= setSrcSpan loc $
- addErrCtxt (derivInstCtxt clas inst_tys) $
+ addErrCtxt (derivInstCtxt the_pred) $
do { -- Check for a bizarre corner case, when the derived instance decl should
-- have form instance C a b => D (T a) where ...
-- Note that 'b' isn't a parameter of T. This gives rise to all sorts
, not (tyVarsOfPred pred `subVarSet` tv_set)]
; mapM_ (addErrTc . badDerivedPred) weird_preds
- ; theta <- simplifyDeriv orig tyvars deriv_rhs
+ ; theta <- simplifyDeriv orig the_pred tyvars deriv_rhs
-- checkValidInstance tyvars theta clas inst_tys
-- Not necessary; see Note [Exotic derived instance contexts]
-- in TcSimplify
-- Hence no need to call:
-- checkValidInstance tyvars theta clas inst_tys
; return (sortLe (<=) theta) } -- Canonicalise before returning the solution
+ where
+ the_pred = mkClassPred clas inst_tys
------------------------------------------------------------------
mkInstance :: OverlapFlag -> ThetaType -> DerivSpec -> Instance
standaloneCtxt ty = hang (ptext (sLit "In the stand-alone deriving instance for"))
2 (quotes (ppr ty))
-derivInstCtxt :: Class -> [Type] -> Message
-derivInstCtxt clas inst_tys
- = ptext (sLit "When deriving the instance for") <+> parens (pprClassPred clas inst_tys)
+derivInstCtxt :: PredType -> Message
+derivInstCtxt pred
+ = ptext (sLit "When deriving the instance for") <+> parens (ppr pred)
badDerivedPred :: PredType -> Message
badDerivedPred pred