#include "HsVersions.h"
-import HsSyn ( Pat(..), HsConDetails(..), HsLit(..), HsOverLit(..), HsExpr(..) )
-import RnHsSyn ( RenamedPat )
-import TcHsSyn ( TcPat, TcId, hsLitType,
+import HsSyn ( Pat(..), LPat, HsConDetails(..), HsLit(..), HsOverLit(..), HsExpr(..) )
+import HsUtils
+import TcHsSyn ( TcId, hsLitType,
mkCoercion, idCoercion, isIdCoercion,
(<$>), PatCoFn )
newMethodFromName, newOverloadedLit, newDicts,
instToId, tcInstDataCon, tcSyntaxName
)
-import Id ( mkLocalId, mkSysLocal )
+import Id ( idType, mkLocalId, mkSysLocal )
import Name ( Name )
import FieldLabel ( fieldLabelName )
-import TcEnv ( tcLookupClass, tcLookupDataCon, tcLookupId )
-import TcMType ( newTyVarTy, zapToType, arityErr )
+import TcEnv ( tcLookupClass, tcLookupLocatedDataCon, tcLookupId )
+import TcMType ( newTyVarTy, arityErr )
import TcType ( TcType, TcTyVar, TcSigmaType,
mkClassPred, liftedTypeKind )
-import TcUnify ( tcSubOff, TcHoleType,
- unifyTauTy, unifyListTy, unifyPArrTy, unifyTupleTy )
-import TcMonoType ( tcHsSigType, UserTypeCtxt(..) )
+import TcUnify ( tcSubOff, Expected(..), readExpectedType, zapExpectedType,
+ unifyTauTy, zapToListTy, zapToPArrTy, zapToTupleTy )
+import TcHsType ( tcHsSigType, UserTypeCtxt(..) )
import TysWiredIn ( stringTy )
import CmdLineOpts ( opt_IrrefutableTuples )
import DataCon ( DataCon, dataConFieldLabels, dataConSourceArity )
-import PrelNames ( eqStringName, eqName, geName, negateName, minusName, cCallableClassName )
+import PrelNames ( eqStringName, eqName, geName, negateName, minusName,
+ integralClassName )
import BasicTypes ( isBoxed )
+import SrcLoc ( Located(..), noLoc, unLoc )
import Bag
import Outputable
import FastString
%************************************************************************
\begin{code}
-type BinderChecker = Name -> TcSigmaType -> TcM (PatCoFn, TcId)
+type BinderChecker = Name -> Expected TcSigmaType -> TcM (PatCoFn, TcId)
-- How to construct a suitable (monomorphic)
-- Id for variables found in the pattern
-- The TcSigmaType is the expected type
-- so there's no polymorphic guy to worry about
tcMonoPatBndr binder_name pat_ty
- = zapToType pat_ty `thenM` \ pat_ty' ->
+ = zapExpectedType pat_ty `thenM` \ pat_ty' ->
-- If there are *no constraints* on the pattern type, we
-- revert to good old H-M typechecking, making
-- the type of the binder into an *ordinary*
\begin{code}
tcPat :: BinderChecker
- -> RenamedPat
+ -> LPat Name
- -> TcHoleType -- Expected type derived from the context
- -- In the case of a function with a rank-2 signature,
- -- this type might be a forall type.
+ -> Expected TcSigmaType -- Expected type derived from the context
+ -- In the case of a function with a rank-2 signature,
+ -- this type might be a forall type.
- -> TcM (TcPat,
+ -> TcM (LPat TcId,
Bag TcTyVar, -- TyVars bound by the pattern
-- These are just the existentially-bound ones.
-- Any tyvars bound by *type signatures* in the
-- local name for each variable.
[Inst]) -- Dicts or methods [see below] bound by the pattern
-- from existential constructor patterns
+tcPat tc_bndr (L span pat) exp_ty
+ = addSrcSpan span $
+ do { (pat', tvs, ids, lie) <- tc_pat tc_bndr pat exp_ty
+ ; return (L span pat', tvs, ids, lie) }
\end{code}
%************************************************************************
\begin{code}
-tcPat tc_bndr pat@(TypePat ty) pat_ty
+tc_pat tc_bndr pat@(TypePat ty) pat_ty
= failWithTc (badTypePat pat)
-tcPat tc_bndr (VarPat name) pat_ty
+tc_pat tc_bndr (VarPat name) pat_ty
= tc_bndr name pat_ty `thenM` \ (co_fn, bndr_id) ->
returnM (co_fn <$> VarPat bndr_id,
- emptyBag, unitBag (name, bndr_id), [])
+ emptyBag, unitBag (name, bndr_id), [])
-tcPat tc_bndr (LazyPat pat) pat_ty
+tc_pat tc_bndr (LazyPat pat) pat_ty
= tcPat tc_bndr pat pat_ty `thenM` \ (pat', tvs, ids, lie_avail) ->
returnM (LazyPat pat', tvs, ids, lie_avail)
-tcPat tc_bndr pat_in@(AsPat name pat) pat_ty
- = tc_bndr name pat_ty `thenM` \ (co_fn, bndr_id) ->
- tcPat tc_bndr pat pat_ty `thenM` \ (pat', tvs, ids, lie_avail) ->
- returnM (co_fn <$> (AsPat bndr_id pat'),
+tc_pat tc_bndr pat_in@(AsPat (L nm_loc name) pat) pat_ty
+ = addSrcSpan nm_loc (tc_bndr name pat_ty) `thenM` \ (co_fn, bndr_id) ->
+ tcPat tc_bndr pat (Check (idType bndr_id)) `thenM` \ (pat', tvs, ids, lie_avail) ->
+ -- NB: if we have:
+ -- \ (y@(x::forall a. a->a)) = e
+ -- we'll fail. The as-pattern infers a monotype for 'y', which then
+ -- fails to unify with the polymorphic type for 'x'. This could be
+ -- fixed, but only with a bit more work.
+ returnM (co_fn <$> (AsPat (L nm_loc bndr_id) pat'),
tvs, (name, bndr_id) `consBag` ids, lie_avail)
-tcPat tc_bndr (WildPat _) pat_ty
- = zapToType pat_ty `thenM` \ pat_ty' ->
+tc_pat tc_bndr (WildPat _) pat_ty
+ = zapExpectedType pat_ty `thenM` \ pat_ty' ->
-- We might have an incoming 'hole' type variable; no annotation
-- so zap it to a type. Rather like tcMonoPatBndr.
returnM (WildPat pat_ty', emptyBag, emptyBag, [])
-tcPat tc_bndr (ParPat parend_pat) pat_ty
+tc_pat tc_bndr (ParPat parend_pat) pat_ty
-- Leave the parens in, so that warnings from the
-- desugarer have parens in them
= tcPat tc_bndr parend_pat pat_ty `thenM` \ (pat', tvs, ids, lie_avail) ->
returnM (ParPat pat', tvs, ids, lie_avail)
-tcPat tc_bndr pat_in@(SigPatIn pat sig) pat_ty
+tc_pat tc_bndr pat_in@(SigPatIn pat sig) pat_ty
= addErrCtxt (patCtxt pat_in) $
tcHsSigType PatSigCtxt sig `thenM` \ sig_ty ->
tcSubPat sig_ty pat_ty `thenM` \ co_fn ->
- tcPat tc_bndr pat sig_ty `thenM` \ (pat', tvs, ids, lie_avail) ->
- returnM (co_fn <$> pat', tvs, ids, lie_avail)
+ tcPat tc_bndr pat (Check sig_ty) `thenM` \ (pat', tvs, ids, lie_avail) ->
+ returnM (co_fn <$> unLoc pat', tvs, ids, lie_avail)
\end{code}
%************************************************************************
\begin{code}
-tcPat tc_bndr pat_in@(ListPat pats _) pat_ty
+tc_pat tc_bndr pat_in@(ListPat pats _) pat_ty
= addErrCtxt (patCtxt pat_in) $
- unifyListTy pat_ty `thenM` \ elem_ty ->
+ zapToListTy pat_ty `thenM` \ elem_ty ->
tcPats tc_bndr pats (repeat elem_ty) `thenM` \ (pats', tvs, ids, lie_avail) ->
returnM (ListPat pats' elem_ty, tvs, ids, lie_avail)
-tcPat tc_bndr pat_in@(PArrPat pats _) pat_ty
+tc_pat tc_bndr pat_in@(PArrPat pats _) pat_ty
= addErrCtxt (patCtxt pat_in) $
- unifyPArrTy pat_ty `thenM` \ elem_ty ->
+ zapToPArrTy pat_ty `thenM` \ elem_ty ->
tcPats tc_bndr pats (repeat elem_ty) `thenM` \ (pats', tvs, ids, lie_avail) ->
returnM (PArrPat pats' elem_ty, tvs, ids, lie_avail)
-tcPat tc_bndr pat_in@(TuplePat pats boxity) pat_ty
+tc_pat tc_bndr pat_in@(TuplePat pats boxity) pat_ty
= addErrCtxt (patCtxt pat_in) $
- unifyTupleTy boxity arity pat_ty `thenM` \ arg_tys ->
+ zapToTupleTy boxity arity pat_ty `thenM` \ arg_tys ->
tcPats tc_bndr pats arg_tys `thenM` \ (pats', tvs, ids, lie_avail) ->
-- possibly do the "make all tuple-pats irrefutable" test:
-- it was easy to do.
possibly_mangled_result
- | opt_IrrefutableTuples && isBoxed boxity = LazyPat unmangled_result
+ | opt_IrrefutableTuples && isBoxed boxity = LazyPat (noLoc unmangled_result)
| otherwise = unmangled_result
in
returnM (possibly_mangled_result, tvs, ids, lie_avail)
%************************************************************************
\begin{code}
-tcPat tc_bndr pat_in@(ConPatIn con_name arg_pats) pat_ty
+tc_pat tc_bndr pat_in@(ConPatIn con_name arg_pats) pat_ty
= addErrCtxt (patCtxt pat_in) $
-- Check that it's a constructor, and instantiate it
- tcLookupDataCon con_name `thenM` \ data_con ->
+ tcLookupLocatedDataCon con_name `thenM` \ data_con ->
tcInstDataCon (PatOrigin pat_in) data_con `thenM` \ (_, ex_dicts1, arg_tys, con_res_ty, ex_tvs) ->
-- Check overall type matches.
%************************************************************************
\begin{code}
-tcPat tc_bndr (LitPat lit@(HsLitLit s _)) pat_ty
- -- cf tcExpr on LitLits
- = tcLookupClass cCallableClassName `thenM` \ cCallableClass ->
- newDicts (LitLitOrigin (unpackFS s))
- [mkClassPred cCallableClass [pat_ty]] `thenM` \ dicts ->
- extendLIEs dicts `thenM_`
- returnM (LitPat (HsLitLit s pat_ty), emptyBag, emptyBag, [])
-
-tcPat tc_bndr pat@(LitPat lit@(HsString _)) pat_ty
- = unifyTauTy pat_ty stringTy `thenM_`
+tc_pat tc_bndr pat@(LitPat lit@(HsString _)) pat_ty
+ = zapExpectedType pat_ty `thenM` \ pat_ty' ->
+ unifyTauTy pat_ty' stringTy `thenM_`
tcLookupId eqStringName `thenM` \ eq_id ->
- returnM (NPatOut lit stringTy (HsVar eq_id `HsApp` HsLit lit),
- emptyBag, emptyBag, [])
+ returnM (NPatOut lit stringTy (nlHsVar eq_id `HsApp` nlHsLit lit),
+ emptyBag, emptyBag, [])
-tcPat tc_bndr (LitPat simple_lit) pat_ty
- = unifyTauTy pat_ty (hsLitType simple_lit) `thenM_`
+tc_pat tc_bndr (LitPat simple_lit) pat_ty
+ = zapExpectedType pat_ty `thenM` \ pat_ty' ->
+ unifyTauTy pat_ty' (hsLitType simple_lit) `thenM_`
returnM (LitPat simple_lit, emptyBag, emptyBag, [])
-tcPat tc_bndr pat@(NPatIn over_lit mb_neg) pat_ty
- = newOverloadedLit origin over_lit pat_ty `thenM` \ pos_lit_expr ->
- newMethodFromName origin pat_ty eqName `thenM` \ eq ->
+tc_pat tc_bndr pat@(NPatIn over_lit mb_neg) pat_ty
+ = zapExpectedType pat_ty `thenM` \ pat_ty' ->
+ newOverloadedLit origin over_lit pat_ty' `thenM` \ pos_lit_expr ->
+ newMethodFromName origin pat_ty' eqName `thenM` \ eq ->
(case mb_neg of
Nothing -> returnM pos_lit_expr -- Positive literal
Just neg -> -- Negative literal
-- The 'negate' is re-mappable syntax
- tcSyntaxName origin pat_ty negateName neg `thenM` \ (neg_expr, _) ->
- returnM (HsApp neg_expr pos_lit_expr)
+ tcSyntaxName origin pat_ty' (negateName, noLoc (HsVar neg)) `thenM` \ (_, neg_expr) ->
+ returnM (mkHsApp neg_expr pos_lit_expr)
) `thenM` \ lit_expr ->
- returnM (NPatOut lit' pat_ty (HsApp (HsVar eq) lit_expr),
- emptyBag, emptyBag, [])
- where
- origin = PatOrigin pat
-
+ let
-- The literal in an NPatIn is always positive...
-- But in NPat, the literal is used to find identical patterns
-- so we must negate the literal when necessary!
- lit' = case (over_lit, mb_neg) of
- (HsIntegral i _, Nothing) -> HsInteger i
- (HsIntegral i _, Just _) -> HsInteger (-i)
- (HsFractional f _, Nothing) -> HsRat f pat_ty
- (HsFractional f _, Just _) -> HsRat (-f) pat_ty
+ lit' = case (over_lit, mb_neg) of
+ (HsIntegral i _, Nothing) -> HsInteger i pat_ty'
+ (HsIntegral i _, Just _) -> HsInteger (-i) pat_ty'
+ (HsFractional f _, Nothing) -> HsRat f pat_ty'
+ (HsFractional f _, Just _) -> HsRat (-f) pat_ty'
+ in
+ returnM (NPatOut lit' pat_ty' (HsApp (nlHsVar eq) lit_expr),
+ emptyBag, emptyBag, [])
+ where
+ origin = PatOrigin pat
\end{code}
%************************************************************************
%************************************************************************
\begin{code}
-tcPat tc_bndr pat@(NPlusKPatIn name lit@(HsIntegral i _) minus_name) pat_ty
- = tc_bndr name pat_ty `thenM` \ (co_fn, bndr_id) ->
- newOverloadedLit origin lit pat_ty `thenM` \ over_lit_expr ->
- newMethodFromName origin pat_ty geName `thenM` \ ge ->
+tc_pat tc_bndr pat@(NPlusKPatIn (L nm_loc name) lit@(HsIntegral i _) minus_name) pat_ty
+ = addSrcSpan nm_loc (tc_bndr name pat_ty) `thenM` \ (co_fn, bndr_id) ->
+ let
+ pat_ty' = idType bndr_id
+ in
+ newOverloadedLit origin lit pat_ty' `thenM` \ over_lit_expr ->
+ newMethodFromName origin pat_ty' geName `thenM` \ ge ->
-- The '-' part is re-mappable syntax
- tcSyntaxName origin pat_ty minusName minus_name `thenM` \ (minus_expr, _) ->
+ tcSyntaxName origin pat_ty' (minusName, noLoc (HsVar minus_name)) `thenM` \ (_, minus_expr) ->
- returnM (NPlusKPatOut bndr_id i
- (SectionR (HsVar ge) over_lit_expr)
+ -- The Report says that n+k patterns must be in Integral
+ -- We may not want this when using re-mappable syntax, though (ToDo?)
+ tcLookupClass integralClassName `thenM` \ icls ->
+ newDicts origin [mkClassPred icls [pat_ty']] `thenM` \ dicts ->
+ extendLIEs dicts `thenM_`
+
+ returnM (NPlusKPatOut (L nm_loc bndr_id) i
+ (SectionR (nlHsVar ge) over_lit_expr)
(SectionR minus_expr over_lit_expr),
emptyBag, unitBag (name, bndr_id), [])
where
origin = PatOrigin pat
\end{code}
+
%************************************************************************
%* *
\subsection{Lists of patterns}
\begin{code}
tcPats :: BinderChecker -- How to deal with variables
- -> [RenamedPat] -> [TcType] -- Excess 'expected types' discarded
- -> TcM ([TcPat],
+ -> [LPat Name] -> [TcType] -- Excess 'expected types' discarded
+ -> TcM ([LPat TcId],
Bag TcTyVar,
Bag (Name, TcId), -- Ids bound by the pattern
[Inst]) -- Dicts bound by the pattern
tcPats tc_bndr [] tys = returnM ([], emptyBag, emptyBag, [])
-tcPats tc_bndr (ty:tys) (pat:pats)
- = tcPat tc_bndr ty pat `thenM` \ (pat', tvs1, ids1, lie_avail1) ->
- tcPats tc_bndr tys pats `thenM` \ (pats', tvs2, ids2, lie_avail2) ->
+tcPats tc_bndr (pat:pats) (ty:tys)
+ = tcPat tc_bndr pat (Check ty) `thenM` \ (pat', tvs1, ids1, lie_avail1) ->
+ tcPats tc_bndr pats tys `thenM` \ (pats', tvs2, ids2, lie_avail2) ->
returnM (pat':pats',
tvs1 `unionBags` tvs2, ids1 `unionBags` ids2,
(arityErr "Constructor" data_con con_arity 2) `thenM_`
-- Check arguments
- tcPat tc_bndr p1 ty1 `thenM` \ (p1', tvs1, ids1, lie_avail1) ->
- tcPat tc_bndr p2 ty2 `thenM` \ (p2', tvs2, ids2, lie_avail2) ->
+ tcPat tc_bndr p1 (Check ty1) `thenM` \ (p1', tvs1, ids1, lie_avail1) ->
+ tcPat tc_bndr p2 (Check ty2) `thenM` \ (p2', tvs2, ids2, lie_avail2) ->
returnM (InfixCon p1' p2',
tvs1 `unionBags` tvs2, ids1 `unionBags` ids2,
tc_fields field_tys []
= returnM ([], emptyBag, emptyBag, [])
- tc_fields field_tys ((field_label, rhs_pat) : rpats)
+ tc_fields field_tys ((L lbl_loc field_label, rhs_pat) : rpats)
= tc_fields field_tys rpats `thenM` \ (rpats', tvs1, ids1, lie_avail1) ->
(case [ty | (f,ty) <- field_tys, f == field_label] of
-- The normal case, when the field comes from the right constructor
(pat_ty : extras) ->
ASSERT( null extras )
- tcLookupId field_label `thenM` \ sel_id ->
+ addSrcSpan lbl_loc (tcLookupId field_label) `thenM` \ sel_id ->
returnM (sel_id, pat_ty)
) `thenM` \ (sel_id, pat_ty) ->
- tcPat tc_bndr rhs_pat pat_ty `thenM` \ (rhs_pat', tvs2, ids2, lie_avail2) ->
+ tcPat tc_bndr rhs_pat (Check pat_ty) `thenM` \ (rhs_pat', tvs2, ids2, lie_avail2) ->
- returnM ((sel_id, rhs_pat') : rpats',
+ returnM ((L lbl_loc sel_id, rhs_pat') : rpats',
tvs1 `unionBags` tvs2,
ids1 `unionBags` ids2,
lie_avail1 ++ lie_avail2)
(forall a. a->a in the example)
\begin{code}
-tcSubPat :: TcSigmaType -> TcHoleType -> TcM PatCoFn
+tcSubPat :: TcSigmaType -> Expected TcSigmaType -> TcM PatCoFn
tcSubPat sig_ty exp_ty
= tcSubOff sig_ty exp_ty `thenM` \ co_fn ->
returnM idCoercion
else
newUnique `thenM` \ uniq ->
+ readExpectedType exp_ty `thenM` \ exp_ty' ->
let
- arg_id = mkSysLocal FSLIT("sub") uniq exp_ty
- the_fn = DictLam [arg_id] (co_fn <$> HsVar arg_id)
- pat_co_fn p = SigPatOut p exp_ty the_fn
+ arg_id = mkSysLocal FSLIT("sub") uniq exp_ty'
+ the_fn = DictLam [arg_id] (noLoc (co_fn <$> HsVar arg_id))
+ pat_co_fn p = SigPatOut (noLoc p) exp_ty' the_fn
in
returnM (mkCoercion pat_co_fn)
\end{code}
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