\section[TcPat]{Typechecking patterns}
\begin{code}
-module TcPat ( tcPat, tcVarPat, badFieldCon, polyPatSig ) where
+module TcPat ( tcPat, tcPatBndr_NoSigs, badFieldCon, polyPatSig ) where
#include "HsVersions.h"
import TcMonad
import Inst ( Inst, OverloadedLit(..), InstOrigin(..),
emptyLIE, plusLIE, LIE,
- newMethod, newMethodWithGivenTy, newOverloadedLit,
+ newMethod, newOverloadedLit,
newDicts, instToIdBndr
)
import Name ( Name, getOccName, getSrcLoc )
import Bag ( Bag )
import CmdLineOpts ( opt_IrrefutableTuples )
import DataCon ( DataCon, dataConSig, dataConFieldLabels, dataConSourceArity )
-import Id ( Id, mkUserId, idType, isDataConId_maybe )
-import Type ( Type, isTauTy, substTopTy, substTopTheta, mkTyConApp )
+import Id ( Id, idType, isDataConId_maybe )
+import Type ( Type, isTauTy, mkTyConApp )
+import Subst ( substTy, substTheta )
import TysPrim ( charPrimTy, intPrimTy, floatPrimTy,
doublePrimTy, addrPrimTy
)
%************************************************************************
\begin{code}
-tcVarPat :: (Name -> Maybe TcId) -- Info about signatures; gives the *monomorphic*
- -- Id for variables with a type signature
- -> Name
-
- -> TcType -- Expected type, derived from the context
- -- In the case of a function with a rank-2 signature,
- -- this type might be a forall type.
- -- INVARIANT: if it is, the foralls will always be visible,
- -- not hidden inside a mutable type variable
-
- -> TcM s TcId -- The monomorphic Id; this is put in the pattern itself
-
-tcVarPat sig_fn binder_name pat_ty
- = case sig_fn binder_name of
- Nothing -> -- Need to make a new, monomorphic, Id
- -- The binder_name is already being used for the polymorphic Id
- newLocalId (getOccName binder_name) pat_ty loc `thenNF_Tc` \ bndr_id ->
- returnTc bndr_id
-
- Just bndr_id -> tcAddSrcLoc loc $
- unifyTauTy (idType bndr_id) pat_ty `thenTc_`
- returnTc bndr_id
+-- This is the right function to pass to tcPat when there are no signatures
+tcPatBndr_NoSigs binder_name pat_ty
+ = -- Need to make a new, monomorphic, Id
+ -- The binder_name is already being used for the polymorphic Id
+ newLocalId (getOccName binder_name) pat_ty loc `thenNF_Tc` \ bndr_id ->
+ returnTc bndr_id
where
loc = getSrcLoc binder_name
\end{code}
%************************************************************************
\begin{code}
-tcPat :: (Name -> Maybe TcId) -- Info about signatures; gives the *monomorphic*
- -- Id for variables with a type signature
+tcPat :: (Name -> TcType -> TcM s TcId) -- How to construct a suitable (monomorphic)
+ -- Id for variables found in the pattern
+ -- The TcType is the expected type, see note below
-> RenamedPat
- -> TcType -- Expected type; see invariant in tcVarPat
+
+ -> TcType -- Expected type derived from the context
+ -- In the case of a function with a rank-2 signature,
+ -- this type might be a forall type.
+ -- INVARIANT: if it is, the foralls will always be visible,
+ -- not hidden inside a mutable type variable
+
-> TcM s (TcPat,
LIE, -- Required by n+k and literal pats
Bag TcTyVar, -- TyVars bound by the pattern
%************************************************************************
\begin{code}
-tcPat sig_fn (VarPatIn name) pat_ty
- = tcVarPat sig_fn name pat_ty `thenTc` \ bndr_id ->
+tcPat tc_bndr (VarPatIn name) pat_ty
+ = tc_bndr name pat_ty `thenTc` \ bndr_id ->
returnTc (VarPat bndr_id, emptyLIE, emptyBag, unitBag (name, bndr_id), emptyLIE)
-tcPat sig_fn (LazyPatIn pat) pat_ty
- = tcPat sig_fn pat pat_ty `thenTc` \ (pat', lie_req, tvs, ids, lie_avail) ->
+tcPat tc_bndr (LazyPatIn pat) pat_ty
+ = tcPat tc_bndr pat pat_ty `thenTc` \ (pat', lie_req, tvs, ids, lie_avail) ->
returnTc (LazyPat pat', lie_req, tvs, ids, lie_avail)
-tcPat sig_fn pat_in@(AsPatIn name pat) pat_ty
- = tcVarPat sig_fn name pat_ty `thenTc` \ bndr_id ->
- tcPat sig_fn pat pat_ty `thenTc` \ (pat', lie_req, tvs, ids, lie_avail) ->
+tcPat tc_bndr pat_in@(AsPatIn name pat) pat_ty
+ = tc_bndr name pat_ty `thenTc` \ bndr_id ->
+ tcPat tc_bndr pat pat_ty `thenTc` \ (pat', lie_req, tvs, ids, lie_avail) ->
tcAddErrCtxt (patCtxt pat_in) $
returnTc (AsPat bndr_id pat', lie_req,
tvs, (name, bndr_id) `consBag` ids, lie_avail)
-tcPat sig_fn WildPatIn pat_ty
+tcPat tc_bndr WildPatIn pat_ty
= returnTc (WildPat pat_ty, emptyLIE, emptyBag, emptyBag, emptyLIE)
-tcPat sig_fn (NegPatIn pat) pat_ty
- = tcPat sig_fn (negate_lit pat) pat_ty
+tcPat tc_bndr (NegPatIn pat) pat_ty
+ = tcPat tc_bndr (negate_lit pat) pat_ty
where
negate_lit (LitPatIn (HsInt i)) = LitPatIn (HsInt (-i))
negate_lit (LitPatIn (HsFrac f)) = LitPatIn (HsFrac (-f))
negate_lit _ = panic "TcPat:negate_pat"
-tcPat sig_fn (ParPatIn parend_pat) pat_ty
- = tcPat sig_fn parend_pat pat_ty
+tcPat tc_bndr (ParPatIn parend_pat) pat_ty
+ = tcPat tc_bndr parend_pat pat_ty
-tcPat sig_fn (SigPatIn pat sig) pat_ty
+tcPat tc_bndr (SigPatIn pat sig) pat_ty
= tcHsType sig `thenTc` \ sig_ty ->
-- Check that the signature isn't a polymorphic one, which
checkTc (isTauTy sig_ty) (polyPatSig sig_ty) `thenTc_`
unifyTauTy pat_ty sig_ty `thenTc_`
- tcPat sig_fn pat sig_ty
+ tcPat tc_bndr pat sig_ty
\end{code}
%************************************************************************
%************************************************************************
\begin{code}
-tcPat sig_fn pat_in@(ListPatIn pats) pat_ty
+tcPat tc_bndr pat_in@(ListPatIn pats) pat_ty
= tcAddErrCtxt (patCtxt pat_in) $
unifyListTy pat_ty `thenTc` \ elem_ty ->
- tcPats sig_fn pats (repeat elem_ty) `thenTc` \ (pats', lie_req, tvs, ids, lie_avail) ->
+ tcPats tc_bndr pats (repeat elem_ty) `thenTc` \ (pats', lie_req, tvs, ids, lie_avail) ->
returnTc (ListPat elem_ty pats', lie_req, tvs, ids, lie_avail)
-tcPat sig_fn pat_in@(TuplePatIn pats boxed) pat_ty
+tcPat tc_bndr pat_in@(TuplePatIn pats boxed) pat_ty
= tcAddErrCtxt (patCtxt pat_in) $
(if boxed
then unifyTupleTy arity pat_ty
else unifyUnboxedTupleTy arity pat_ty) `thenTc` \ arg_tys ->
- tcPats sig_fn pats arg_tys `thenTc` \ (pats', lie_req, tvs, ids, lie_avail) ->
+ tcPats tc_bndr pats arg_tys `thenTc` \ (pats', lie_req, tvs, ids, lie_avail) ->
-- possibly do the "make all tuple-pats irrefutable" test:
let
%************************************************************************
\begin{code}
-tcPat sig_fn pat@(ConPatIn name arg_pats) pat_ty
- = tcConPat sig_fn pat name arg_pats pat_ty
+tcPat tc_bndr pat@(ConPatIn name arg_pats) pat_ty
+ = tcConPat tc_bndr pat name arg_pats pat_ty
-tcPat sig_fn pat@(ConOpPatIn pat1 op _ pat2) pat_ty
- = tcConPat sig_fn pat op [pat1, pat2] pat_ty
+tcPat tc_bndr pat@(ConOpPatIn pat1 op _ pat2) pat_ty
+ = tcConPat tc_bndr pat op [pat1, pat2] pat_ty
\end{code}
%************************************************************************
\begin{code}
-tcPat sig_fn pat@(RecPatIn name rpats) pat_ty
+tcPat tc_bndr pat@(RecPatIn name rpats) pat_ty
= tcAddErrCtxt (patCtxt pat) $
-- Check the constructor itself
tc_fields field_tys rpats `thenTc` \ (rpats', lie_req1, tvs1, ids1, lie_avail1) ->
tcLookupValue field_label `thenNF_Tc` \ sel_id ->
- tcPat sig_fn rhs_pat rhs_ty `thenTc` \ (rhs_pat', lie_req2, tvs2, ids2, lie_avail2) ->
+ tcPat tc_bndr rhs_pat rhs_ty `thenTc` \ (rhs_pat', lie_req2, tvs2, ids2, lie_avail2) ->
returnTc ((sel_id, rhs_pat', pun_flag) : rpats',
lie_req1 `plusLIE` lie_req2,
%************************************************************************
\begin{code}
-tcPat sig_fn (LitPatIn lit@(HsChar _)) pat_ty = tcSimpleLitPat lit charTy pat_ty
-tcPat sig_fn (LitPatIn lit@(HsIntPrim _)) pat_ty = tcSimpleLitPat lit intPrimTy pat_ty
-tcPat sig_fn (LitPatIn lit@(HsCharPrim _)) pat_ty = tcSimpleLitPat lit charPrimTy pat_ty
-tcPat sig_fn (LitPatIn lit@(HsStringPrim _)) pat_ty = tcSimpleLitPat lit addrPrimTy pat_ty
-tcPat sig_fn (LitPatIn lit@(HsFloatPrim _)) pat_ty = tcSimpleLitPat lit floatPrimTy pat_ty
-tcPat sig_fn (LitPatIn lit@(HsDoublePrim _)) pat_ty = tcSimpleLitPat lit doublePrimTy pat_ty
-
-tcPat sig_fn (LitPatIn lit@(HsLitLit s)) pat_ty = tcSimpleLitPat lit intTy pat_ty
+tcPat tc_bndr (LitPatIn lit@(HsChar _)) pat_ty = tcSimpleLitPat lit charTy pat_ty
+tcPat tc_bndr (LitPatIn lit@(HsIntPrim _)) pat_ty = tcSimpleLitPat lit intPrimTy pat_ty
+tcPat tc_bndr (LitPatIn lit@(HsCharPrim _)) pat_ty = tcSimpleLitPat lit charPrimTy pat_ty
+tcPat tc_bndr (LitPatIn lit@(HsStringPrim _)) pat_ty = tcSimpleLitPat lit addrPrimTy pat_ty
+tcPat tc_bndr (LitPatIn lit@(HsFloatPrim _)) pat_ty = tcSimpleLitPat lit floatPrimTy pat_ty
+tcPat tc_bndr (LitPatIn lit@(HsDoublePrim _)) pat_ty = tcSimpleLitPat lit doublePrimTy pat_ty
+
+tcPat tc_bndr (LitPatIn lit@(HsLitLit s)) pat_ty = tcSimpleLitPat lit intTy pat_ty
-- This one looks weird!
\end{code}
%************************************************************************
\begin{code}
-tcPat sig_fn pat@(LitPatIn lit@(HsString str)) pat_ty
+tcPat tc_bndr pat@(LitPatIn lit@(HsString str)) pat_ty
= unifyTauTy pat_ty stringTy `thenTc_`
tcLookupValueByKey eqClassOpKey `thenNF_Tc` \ sel_id ->
newMethod (PatOrigin pat) sel_id [stringTy] `thenNF_Tc` \ (lie, eq_id) ->
returnTc (NPat lit stringTy comp_op, lie, emptyBag, emptyBag, emptyLIE)
-tcPat sig_fn pat@(LitPatIn lit@(HsInt i)) pat_ty
+tcPat tc_bndr pat@(LitPatIn lit@(HsInt i)) pat_ty
= tcOverloadedLitPat pat lit (OverloadedIntegral i) pat_ty
-tcPat sig_fn pat@(LitPatIn lit@(HsFrac f)) pat_ty
+tcPat tc_bndr pat@(LitPatIn lit@(HsFrac f)) pat_ty
= tcOverloadedLitPat pat lit (OverloadedFractional f) pat_ty
-tcPat sig_fn pat@(NPlusKPatIn name lit@(HsInt i)) pat_ty
- = tcVarPat sig_fn name pat_ty `thenTc` \ bndr_id ->
+tcPat tc_bndr pat@(NPlusKPatIn name lit@(HsInt i)) pat_ty
+ = tc_bndr name pat_ty `thenTc` \ bndr_id ->
tcLookupValueByKey geClassOpKey `thenNF_Tc` \ ge_sel_id ->
tcLookupValueByKey minusClassOpKey `thenNF_Tc` \ minus_sel_id ->
where
origin = PatOrigin pat
-tcPat sig_fn (NPlusKPatIn pat other) pat_ty
+tcPat tc_bndr (NPlusKPatIn pat other) pat_ty
= panic "TcPat:NPlusKPat: not an HsInt literal"
\end{code}
Helper functions
\begin{code}
-tcPats :: (Name -> Maybe TcId) -- Info about signatures
- -> [RenamedPat] -> [TcType] -- Excess 'expected types' discarded
+tcPats :: (Name -> TcType -> TcM s TcId) -- How to deal with variables
+ -> [RenamedPat] -> [TcType] -- Excess 'expected types' discarded
-> TcM s ([TcPat],
LIE, -- Required by n+k and literal pats
Bag TcTyVar,
Bag (Name, TcId), -- Ids bound by the pattern
LIE) -- Dicts bound by the pattern
-tcPats sig_fn [] tys = returnTc ([], emptyLIE, emptyBag, emptyBag, emptyLIE)
+tcPats tc_bndr [] tys = returnTc ([], emptyLIE, emptyBag, emptyBag, emptyLIE)
-tcPats sig_fn (ty:tys) (pat:pats)
- = tcPat sig_fn ty pat `thenTc` \ (pat', lie_req1, tvs1, ids1, lie_avail1) ->
- tcPats sig_fn tys pats `thenTc` \ (pats', lie_req2, tvs2, ids2, lie_avail2) ->
+tcPats tc_bndr (ty:tys) (pat:pats)
+ = tcPat tc_bndr ty pat `thenTc` \ (pat', lie_req1, tvs1, ids1, lie_avail1) ->
+ tcPats tc_bndr tys pats `thenTc` \ (pats', lie_req2, tvs2, ids2, lie_avail2) ->
returnTc (pat':pats', lie_req1 `plusLIE` lie_req2,
tvs1 `unionBags` tvs2, ids1 `unionBags` ids2,
in
tcInstTyVars (ex_tvs ++ tvs) `thenNF_Tc` \ (all_tvs', ty_args', tenv) ->
let
- ex_theta' = substTopTheta tenv ex_theta
- arg_tys' = map (substTopTy tenv) arg_tys
+ ex_theta' = substTheta tenv ex_theta
+ arg_tys' = map (substTy tenv) arg_tys
n_ex_tvs = length ex_tvs
ex_tvs' = take n_ex_tvs all_tvs'
------------------------------------------------------
\begin{code}
-tcConPat sig_fn pat con_name arg_pats pat_ty
+tcConPat tc_bndr pat con_name arg_pats pat_ty
= tcAddErrCtxt (patCtxt pat) $
-- Check the constructor itself
(arityErr "Constructor" data_con con_arity no_of_args) `thenTc_`
-- Check arguments
- tcPats sig_fn arg_pats arg_tys' `thenTc` \ (arg_pats', lie_req, tvs, ids, lie_avail2) ->
+ tcPats tc_bndr arg_pats arg_tys' `thenTc` \ (arg_pats', lie_req, tvs, ids, lie_avail2) ->
returnTc (ConPat data_con pat_ty ex_tvs' dicts arg_pats',
lie_req,
projects / ghc-hetmet.git / blobdiff