import TcEnv ( tcExtendLocalValEnv,
newSpecPragmaId, newLocalId
)
-import TcSimplify ( tcSimplifyInfer, tcSimplifyInferCheck, tcSimplifyCheck, tcSimplifyToDicts )
+import TcSimplify ( tcSimplifyInfer, tcSimplifyInferCheck, tcSimplifyRestricted, tcSimplifyToDicts )
import TcMonoType ( tcHsSigType, checkSigTyVars,
TcSigInfo(..), tcTySig, maybeSig, sigCtxt
)
import IdInfo ( InlinePragInfo(..) )
import Name ( Name, getOccName, getSrcLoc )
import NameSet
-import Type ( mkTyVarTy, tyVarsOfTypes,
- mkForAllTys, mkFunTys, tyVarsOfType,
+import Type ( mkTyVarTy, mkForAllTys, mkFunTys, tyVarsOfType,
mkPredTy, mkForAllTy, isUnLiftedType,
unliftedTypeKind, liftedTypeKind, openTypeKind
)
import VarSet
import Bag
import Util ( isIn )
-import ListSetOps ( minusList )
import Maybes ( maybeToBool )
import BasicTypes ( TopLevelFlag(..), RecFlag(..), isNonRec, isNotTopLevel )
import FiniteMap ( listToFM, lookupFM )
in
-- GENERALISE
+ tcAddSrcLoc (minimum (map getSrcLoc binder_names)) $
+ tcAddErrCtxt (genCtxt binder_names) $
generalise binder_names mbind tau_tvs lie_req tc_ty_sigs
`thenTc` \ (tc_tyvars_to_gen, lie_free, dict_binds, dict_ids) ->
-- at all.
in
+ traceTc (text "binding:" <+> ppr ((zonked_dict_ids, dict_binds),
+ exports, [idType poly_id | (_, poly_id, _) <- exports])) `thenTc_`
+
-- BUILD RESULTS
returnTc (
- -- pprTrace "binding.." (ppr ((zonked_dict_ids, dict_binds),
- -- exports, [idType poly_id | (_, poly_id, _) <- exports])) $
AbsBinds real_tyvars_to_gen
zonked_dict_ids
exports
%************************************************************************
\begin{code}
-generalise_help doc tau_tvs lie_req sigs
+generalise binder_names mbind tau_tvs lie_req sigs
+ | not is_unrestricted -- RESTRICTED CASE
+ = -- Check signature contexts are empty
+ checkTc (all is_mono_sig sigs)
+ (restrictedBindCtxtErr binder_names) `thenTc_`
------------------------
- | null sigs
- = -- INFERENCE CASE: Unrestricted group, no type signatures
- tcSimplifyInfer doc
- tau_tvs lie_req
+ -- Now simplify with exactly that set of tyvars
+ -- We have to squash those Methods
+ tcSimplifyRestricted doc tau_tvs lie_req `thenTc` \ (qtvs, lie_free, binds) ->
------------------------
- | otherwise
+ -- Check that signature type variables are OK
+ checkSigsTyVars sigs `thenTc_`
+
+ returnTc (qtvs, lie_free, binds, [])
+
+ | null sigs -- UNRESTRICTED CASE, NO TYPE SIGS
+ = tcSimplifyInfer doc tau_tvs lie_req
+
+ | otherwise -- UNRESTRICTED CASE, WITH TYPE SIGS
= -- CHECKING CASE: Unrestricted group, there are type signatures
-- Check signature contexts are empty
checkSigsCtxts sigs `thenTc` \ (sig_avails, sig_dicts) ->
returnTc (forall_tvs, lie_free, dict_binds, sig_dicts)
-generalise binder_names mbind tau_tvs lie_req sigs
- | is_unrestricted -- UNRESTRICTED CASE
- = generalise_help doc tau_tvs lie_req sigs
-
- | otherwise -- RESTRICTED CASE
- = -- Do a simplification to decide what type variables
- -- are constrained. We can't just take the free vars
- -- of lie_req because that'll have methods that may
- -- incidentally mention entirely unconstrained variables
- -- e.g. a call to f :: Eq a => a -> b -> b
- -- Here, b is unconstrained. A good example would be
- -- foo = f (3::Int)
- -- We want to infer the polymorphic type
- -- foo :: forall b. b -> b
- generalise_help doc tau_tvs lie_req sigs `thenTc` \ (forall_tvs, lie_free, dict_binds, dict_ids) ->
-
- -- Check signature contexts are empty
- checkTc (null sigs || null dict_ids)
- (restrictedBindCtxtErr binder_names) `thenTc_`
-
- -- Identify constrained tyvars
- let
- constrained_tvs = varSetElems (tyVarsOfTypes (map idType dict_ids))
- -- The dict_ids are fully zonked
- final_forall_tvs = forall_tvs `minusList` constrained_tvs
- in
-
- -- Now simplify with exactly that set of tyvars
- -- We have to squash those Methods
- tcSimplifyCheck doc final_forall_tvs [] lie_req `thenTc` \ (lie_free, binds) ->
-
- returnTc (final_forall_tvs, lie_free, binds, [])
-
where
is_unrestricted | opt_NoMonomorphismRestriction = True
| otherwise = isUnRestrictedGroup tysig_names mbind
tysig_names = [name | (TySigInfo name _ _ _ _ _ _ _) <- sigs]
+ is_mono_sig (TySigInfo _ _ _ theta _ _ _ _) = null theta
- doc | null sigs = ptext SLIT("banding(s) for") <+> pprBinders binder_names
- | otherwise = ptext SLIT("type signature(s) for") <+> pprBinders binder_names
+ doc = ptext SLIT("type signature(s) for") <+> pprBinders binder_names
-----------------------
-- CHECK THAT ALL THE SIGNATURE CONTEXTS ARE UNIFIABLE
-- We unify them because, with polymorphic recursion, their types
-- might not otherwise be related. This is a rather subtle issue.
-- ToDo: amplify
-checkSigsCtxts sigs@(TySigInfo _ id1 sig_tvs theta1 _ _ _ _ : other_sigs)
- = mapTc_ check_one other_sigs `thenTc_`
+checkSigsCtxts sigs@(TySigInfo _ id1 sig_tvs theta1 _ _ _ src_loc : other_sigs)
+ = tcAddSrcLoc src_loc $
+ mapTc_ check_one other_sigs `thenTc_`
if null theta1 then
returnTc ([], []) -- Non-overloaded type signatures
else
sig_meths = concat [insts | TySigInfo _ _ _ _ _ _ insts _ <- sigs]
check_one sig@(TySigInfo _ id _ theta _ _ _ src_loc)
- = tcAddSrcLoc src_loc $
- tcAddErrCtxt (sigContextsCtxt id1 id) $
+ = tcAddErrCtxt (sigContextsCtxt id1 id) $
checkTc (length theta == n_sig1_theta) sigContextsErr `thenTc_`
unifyTauTyLists sig1_dict_tys (map mkPredTy theta)
4 (vcat [ptext SLIT("in a binding group for") <+> pprBinders binder_names,
ptext SLIT("that falls under the monomorphism restriction")])
+genCtxt binder_names
+ = ptext SLIT("When generalising the type(s) for") <+> pprBinders binder_names
+
-- Used in error messages
-pprBinders bndrs = braces (pprWithCommas ppr bndrs)
+pprBinders bndrs = pprWithCommas ppr bndrs
\end{code}
projects / ghc-hetmet.git / blobdiff