import CmdLineOpts ( opt_NoMonomorphismRestriction )
import HsSyn ( HsExpr(..), HsBinds(..), MonoBinds(..), Sig(..),
Match(..), HsMatchContext(..),
- collectMonoBinders, andMonoBinds
+ collectMonoBinders, andMonoBinds,
+ collectSigTysFromMonoBinds
)
import RnHsSyn ( RenamedHsBinds, RenamedSig, RenamedMonoBinds )
import TcHsSyn ( TcMonoBinds, TcId, zonkId, mkHsLet )
import Inst ( LIE, emptyLIE, mkLIE, plusLIE, InstOrigin(..),
newDicts, instToId
)
-import TcEnv ( tcExtendLocalValEnv,
- newSpecPragmaId, newLocalId
- )
+import TcEnv ( tcExtendLocalValEnv, newLocalName )
+import TcUnify ( unifyTauTyLists, checkSigTyVars, sigCtxt )
import TcSimplify ( tcSimplifyInfer, tcSimplifyInferCheck, tcSimplifyRestricted, tcSimplifyToDicts )
-import TcMonoType ( tcHsSigType, UserTypeCtxt(..), checkSigTyVars,
- TcSigInfo(..), tcTySig, maybeSig, sigCtxt
+import TcMonoType ( tcHsSigType, UserTypeCtxt(..),
+ TcSigInfo(..), tcTySig, maybeSig, tcAddScopedTyVars
)
-import TcPat ( tcPat )
+import TcPat ( tcPat, tcSubPat, tcMonoPatBndr )
import TcSimplify ( bindInstsOfLocalFuns )
-import TcMType ( newTyVarTy, newTyVar,
- zonkTcTyVarToTyVar,
- unifyTauTy, unifyTauTyLists
+import TcMType ( newTyVar, newTyVarTy, newHoleTyVarTy,
+ zonkTcTyVarToTyVar
)
import TcType ( mkTyVarTy, mkForAllTys, mkFunTys, tyVarsOfType,
mkPredTy, mkForAllTy, isUnLiftedType,
)
import CoreFVs ( idFreeTyVars )
-import Id ( mkLocalId, setInlinePragma )
+import Id ( mkLocalId, mkSpecPragmaId, setInlinePragma )
import Var ( idType, idName )
-import Name ( Name, getOccName, getSrcLoc )
+import Name ( Name, getSrcLoc )
import NameSet
import Var ( tyVarKind )
import VarSet
do_next
tc_binds_and_then top_lvl combiner (MonoBind bind sigs is_rec) do_next
- = -- TYPECHECK THE SIGNATURES
+ = -- BRING ANY SCOPED TYPE VARIABLES INTO SCOPE
+ -- Notice that they scope over
+ -- a) the type signatures in the binding group
+ -- b) the bindings in the group
+ -- c) the scope of the binding group (the "in" part)
+ tcAddScopedTyVars (collectSigTysFromMonoBinds bind) $
+
+ -- TYPECHECK THE SIGNATURES
mapTc tcTySig [sig | sig@(Sig name _ _) <- sigs] `thenTc` \ tc_ty_sigs ->
tcBindWithSigs top_lvl bind tc_ty_sigs
mapNF_Tc zonkId dict_ids `thenNF_Tc` \ zonked_dict_ids ->
mapNF_Tc zonkId mono_ids `thenNF_Tc` \ zonked_mono_ids ->
- -- CHECK FOR BOGUS UNLIFTED BINDINGS
- checkUnliftedBinds top_lvl is_rec real_tyvars_to_gen mbind zonked_mono_ids `thenTc_`
-
-- BUILD THE POLYMORPHIC RESULT IDs
let
exports = zipWith mk_export binder_names zonked_mono_ids
+ poly_ids = [poly_id | (_, poly_id, _) <- exports]
dict_tys = map idType zonked_dict_ids
inlines = mkNameSet [name | InlineSig True name _ loc <- inline_sigs]
new_poly_id = mkLocalId binder_name poly_ty
poly_ty = mkForAllTys real_tyvars_to_gen
- $ mkFunTys dict_tys
- $ idType zonked_mono_id
+ $ mkFunTys dict_tys
+ $ idType zonked_mono_id
-- It's important to build a fully-zonked poly_ty, because
-- we'll slurp out its free type variables when extending the
-- local environment (tcExtendLocalValEnv); if it's not zonked
in
traceTc (text "binding:" <+> ppr ((zonked_dict_ids, dict_binds),
- exports, [idType poly_id | (_, poly_id, _) <- exports])) `thenTc_`
+ exports, map idType poly_ids)) `thenTc_`
+
+ -- Check for an unlifted, non-overloaded group
+ -- In that case we must make extra checks
+ if any (isUnLiftedType . idType) zonked_mono_ids && null zonked_dict_ids
+ then -- Some bindings are unlifted
+ checkUnliftedBinds top_lvl is_rec real_tyvars_to_gen mbind `thenTc_`
+
+ returnTc (
+ AbsBinds [] [] exports inlines mbind',
+ lie_req, -- Do not generate even any x=y bindings
+ poly_ids
+ )
- -- BUILD RESULTS
+ else -- The normal case
returnTc (
AbsBinds real_tyvars_to_gen
zonked_dict_ids
exports
inlines
(dict_binds `andMonoBinds` mbind'),
- lie_free,
- [poly_id | (_, poly_id, _) <- exports]
+ lie_free, poly_ids
)
attachNoInlinePrag no_inlines bndr
Just prag -> bndr `setInlinePragma` prag
Nothing -> bndr
-checkUnliftedBinds top_lvl is_rec real_tyvars_to_gen mbind zonked_mono_ids
+-- Check that non-overloaded unlifted bindings are
+-- a) non-recursive,
+-- b) not top level,
+-- c) non-polymorphic
+-- d) not a multiple-binding group (more or less implied by (a))
+
+checkUnliftedBinds top_lvl is_rec real_tyvars_to_gen mbind
= ASSERT( not (any ((eqKind unliftedTypeKind) . tyVarKind) real_tyvars_to_gen) )
-- The instCantBeGeneralised stuff in tcSimplify should have
-- already raised an error if we're trying to generalise an
-- because we have more precise origin information.
-- That's why we just use an ASSERT here.
- -- Check that pattern-bound variables are not unlifted
- (if or [ (idName id `elem` pat_binders) && isUnLiftedType (idType id)
- | id <- zonked_mono_ids ] then
- addErrTc (unliftedBindErr "Pattern" mbind)
- else
- returnTc ()
- ) `thenTc_`
-
- -- Unlifted bindings must be non-recursive,
- -- not top level, non-polymorphic, and not pattern bound
- if any (isUnLiftedType . idType) zonked_mono_ids then
- checkTc (isNotTopLevel top_lvl)
- (unliftedBindErr "Top-level" mbind) `thenTc_`
- checkTc (isNonRec is_rec)
- (unliftedBindErr "Recursive" mbind) `thenTc_`
- checkTc (null real_tyvars_to_gen)
- (unliftedBindErr "Polymorphic" mbind)
- else
- returnTc ()
+ checkTc (isNotTopLevel top_lvl)
+ (unliftedBindErr "Top-level" mbind) `thenTc_`
+ checkTc (isNonRec is_rec)
+ (unliftedBindErr "Recursive" mbind) `thenTc_`
+ checkTc (single_bind mbind)
+ (unliftedBindErr "Multiple" mbind) `thenTc_`
+ checkTc (null real_tyvars_to_gen)
+ (unliftedBindErr "Polymorphic" mbind)
where
- pat_binders :: [Name]
- pat_binders = collectMonoBinders (justPatBindings mbind EmptyMonoBinds)
-
- justPatBindings bind@(PatMonoBind _ _ _) binds = bind `andMonoBinds` binds
- justPatBindings (AndMonoBinds b1 b2) binds =
- justPatBindings b1 (justPatBindings b2 binds)
- justPatBindings other_bind binds = binds
+ single_bind (PatMonoBind _ _ _) = True
+ single_bind (FunMonoBind _ _ _ _) = True
+ single_bind other = False
\end{code}
checkSigsTyVars sigs = mapTc_ check_one sigs
where
check_one (TySigInfo _ id sig_tyvars sig_theta sig_tau _ _ src_loc)
- = tcAddSrcLoc src_loc $
- tcAddErrCtxtM (sigCtxt (sig_msg id) sig_tyvars sig_theta sig_tau) $
+ = tcAddSrcLoc src_loc $
+ tcAddErrCtxt (ptext SLIT("When checking the type signature for")
+ <+> quotes (ppr id)) $
+ tcAddErrCtxtM (sigCtxt sig_tyvars sig_theta sig_tau) $
checkSigTyVars sig_tyvars (idFreeTyVars id)
-
- sig_msg id = ptext SLIT("When checking the type signature for") <+> quotes (ppr id)
\end{code}
@getTyVarsToGen@ decides what type variables to generalise over.
isUnRestrictedGroup sigs (PatMonoBind other _ _) = False
isUnRestrictedGroup sigs (VarMonoBind v _) = v `is_elem` sigs
-isUnRestrictedGroup sigs (FunMonoBind v _ matches _) = any isUnRestrictedMatch matches ||
+isUnRestrictedGroup sigs (FunMonoBind v _ matches _) = isUnRestrictedMatch matches ||
v `is_elem` sigs
isUnRestrictedGroup sigs (AndMonoBinds mb1 mb2) = isUnRestrictedGroup sigs mb1 &&
isUnRestrictedGroup sigs mb2
isUnRestrictedGroup sigs EmptyMonoBinds = True
-isUnRestrictedMatch (Match _ [] Nothing _) = False -- No args, no signature
-isUnRestrictedMatch other = True -- Some args or a signature
+isUnRestrictedMatch (Match [] _ _ : _) = False -- No args => like a pattern binding
+isUnRestrictedMatch other = True -- Some args => a function binding
\end{code}
returnTc (mbinds', lie_req_pat `plusLIE` lie_req_rhss, names, mono_ids)
where
- -- This function is used when dealing with a LHS binder;
- -- we make a monomorphic version of the Id.
- -- We check for a type signature; if there is one, we use the mono_id
- -- from the signature. This is how we make sure the tau part of the
- -- signature actually maatches the type of the LHS; then tc_mb_pats
- -- ensures the LHS and RHS have the same type
-
- tc_pat_bndr name pat_ty
- = case maybeSig tc_ty_sigs name of
- Nothing
- -> newLocalId (getOccName name) pat_ty (getSrcLoc name)
-
- Just (TySigInfo _ _ _ _ _ mono_id _ _)
- -> tcAddSrcLoc (getSrcLoc name) $
- unifyTauTy (idType mono_id) pat_ty `thenTc_`
- returnTc mono_id
-
mk_bind (name, mono_id) = case maybeSig tc_ty_sigs name of
Nothing -> (name, mono_id)
Just (TySigInfo name poly_id _ _ _ _ _ _) -> (name, poly_id)
lie_avail1 `plusLIE` lie_avail2)
tc_mb_pats (FunMonoBind name inf matches locn)
- = newTyVarTy kind `thenNF_Tc` \ bndr_ty ->
- tc_pat_bndr name bndr_ty `thenTc` \ bndr_id ->
+ = (case maybeSig tc_ty_sigs name of
+ Just (TySigInfo _ _ _ _ _ mono_id _ _)
+ -> returnNF_Tc mono_id
+ Nothing -> newLocalName name `thenNF_Tc` \ bndr_name ->
+ newTyVarTy openTypeKind `thenNF_Tc` \ bndr_ty ->
+ -- NB: not a 'hole' tyvar; since there is no type
+ -- signature, we revert to ordinary H-M typechecking
+ -- which means the variable gets an inferred tau-type
+ returnNF_Tc (mkLocalId bndr_name bndr_ty)
+ ) `thenNF_Tc` \ bndr_id ->
let
+ bndr_ty = idType bndr_id
complete_it xve = tcAddSrcLoc locn $
tcMatchesFun xve name bndr_ty matches `thenTc` \ (matches', lie) ->
returnTc (FunMonoBind bndr_id inf matches' locn, lie)
tc_mb_pats bind@(PatMonoBind pat grhss locn)
= tcAddSrcLoc locn $
- newTyVarTy kind `thenNF_Tc` \ pat_ty ->
+ newHoleTyVarTy `thenNF_Tc` \ pat_ty ->
-- Now typecheck the pattern
- -- We don't support binding fresh (not-already-in-scope) scoped
+ -- We do now support binding fresh (not-already-in-scope) scoped
-- type variables in the pattern of a pattern binding.
- -- For example, this is illegal:
+ -- For example, this is now legal:
-- (x::a, y::b) = e
- -- whereas this is ok
- -- (x::Int, y::Bool) = e
- --
- -- We don't check explicitly for this problem. Instead, we simply
- -- type check the pattern with tcPat. If the pattern mentions any
- -- fresh tyvars we simply get an out-of-scope type variable error
+ -- The type variables are brought into scope in tc_binds_and_then,
+ -- so we don't have to do anything here.
+
tcPat tc_pat_bndr pat pat_ty `thenTc` \ (pat', lie_req, tvs, ids, lie_avail) ->
let
complete_it xve = tcAddSrcLoc locn $
in
returnTc (complete_it, lie_req, tvs, ids, lie_avail)
- -- Figure out the appropriate kind for the pattern,
- -- and generate a suitable type variable
- kind = case is_rec of
- Recursive -> liftedTypeKind -- Recursive, so no unlifted types
- NonRecursive -> openTypeKind -- Non-recursive, so we permit unlifted types
+ -- tc_pat_bndr is used when dealing with a LHS binder in a pattern.
+ -- If there was a type sig for that Id, we want to make it much
+ -- as if that type signature had been on the binder as a SigPatIn.
+ -- We check for a type signature; if there is one, we use the mono_id
+ -- from the signature. This is how we make sure the tau part of the
+ -- signature actually matches the type of the LHS; then tc_mb_pats
+ -- ensures the LHS and RHS have the same type
+
+ tc_pat_bndr name pat_ty
+ = case maybeSig tc_ty_sigs name of
+ Nothing
+ -> newLocalName name `thenNF_Tc` \ bndr_name ->
+ tcMonoPatBndr bndr_name pat_ty
+
+ Just (TySigInfo _ _ _ _ _ mono_id _ _)
+ -> tcAddSrcLoc (getSrcLoc name) $
+ tcSubPat pat_ty (idType mono_id) `thenTc` \ (co_fn, lie) ->
+ returnTc (co_fn, lie, mono_id)
\end{code}
-- Just specialise "f" by building a SpecPragmaId binding
-- It is the thing that makes sure we don't prematurely
-- dead-code-eliminate the binding we are really interested in.
- newSpecPragmaId name sig_ty `thenNF_Tc` \ spec_id ->
+ newLocalName name `thenNF_Tc` \ spec_name ->
+ let
+ spec_bind = VarMonoBind (mkSpecPragmaId spec_name sig_ty)
+ (mkHsLet spec_binds spec_expr)
+ in
-- Do the rest and combine
tcSpecSigs sigs `thenTc` \ (binds_rest, lie_rest) ->
- returnTc (binds_rest `andMonoBinds` VarMonoBind spec_id (mkHsLet spec_binds spec_expr),
+ returnTc (binds_rest `andMonoBinds` spec_bind,
lie_rest `plusLIE` mkLIE spec_dicts)
tcSpecSigs (other_sig : sigs) = tcSpecSigs sigs
= ptext SLIT("When generalising the type(s) for") <+> pprBinders binder_names
-- Used in error messages
-pprBinders bndrs = pprWithCommas ppr bndrs
+-- Use quotes for a single one; they look a bit "busy" for several
+pprBinders [bndr] = quotes (ppr bndr)
+pprBinders bndrs = pprWithCommas ppr bndrs
\end{code}
projects / ghc-hetmet.git / blobdiff