\section[TcPat]{Typechecking patterns}
\begin{code}
-module TcPat ( tcPat, tcPatBndr_NoSigs, badFieldCon, polyPatSig ) where
+module TcPat ( tcPat, tcMonoPatBndr, simpleHsLitTy, badFieldCon, polyPatSig ) where
#include "HsVersions.h"
-import {-# SOURCE #-} TcExpr( tcExpr )
-
-import HsSyn ( InPat(..), OutPat(..), HsLit(..), HsExpr(..), Sig(..) )
+import HsSyn ( InPat(..), OutPat(..), HsLit(..), HsOverLit(..), HsExpr(..) )
import RnHsSyn ( RenamedPat )
import TcHsSyn ( TcPat, TcId )
import TcMonad
-import Inst ( Inst, OverloadedLit(..), InstOrigin(..),
- emptyLIE, plusLIE, LIE,
- newMethod, newOverloadedLit, newDicts, newClassDicts
+import Inst ( InstOrigin(..),
+ emptyLIE, plusLIE, LIE, mkLIE, unitLIE, instToId,
+ newMethod, newOverloadedLit, newDicts
)
-import Name ( Name, getOccName, getSrcLoc )
+import Id ( mkLocalId )
+import Name ( Name )
import FieldLabel ( fieldLabelName )
-import TcEnv ( tcLookupValue, tcLookupClassByKey,
- tcLookupValueByKey, newLocalId, badCon
- )
+import TcEnv ( tcLookupClass, tcLookupDataCon, tcLookupGlobalId, tcLookupSyntaxId )
import TcType ( TcType, TcTyVar, tcInstTyVars, newTyVarTy )
import TcMonoType ( tcHsSigType )
-import TcUnify ( unifyTauTy, unifyListTy,
- unifyTupleTy, unifyUnboxedTupleTy
- )
+import TcUnify ( unifyTauTy, unifyListTy, unifyTupleTy )
-import Bag ( Bag )
import CmdLineOpts ( opt_IrrefutableTuples )
-import DataCon ( DataCon, dataConSig, dataConFieldLabels,
+import DataCon ( dataConSig, dataConFieldLabels,
dataConSourceArity
)
-import Id ( Id, idType, isDataConWrapId_maybe )
-import Type ( Type, isTauTy, mkTyConApp, mkClassPred, boxedTypeKind )
-import PprType ( {- instance Outputable Type -} )
-import Subst ( substTy, substClasses )
+import Type ( isTauTy, mkTyConApp, mkClassPred, liftedTypeKind )
+import Subst ( substTy, substTheta )
import TysPrim ( charPrimTy, intPrimTy, floatPrimTy,
doublePrimTy, addrPrimTy
)
-import TysWiredIn ( charTy, stringTy, intTy )
-import SrcLoc ( SrcLoc )
-import Unique ( eqClassOpKey, geClassOpKey, minusClassOpKey,
- cCallableClassKey
- )
+import TysWiredIn ( charTy, stringTy, intTy, integerTy )
+import PrelNames ( minusName, eqStringName, eqName, geName, cCallableClassName )
+import BasicTypes ( isBoxed )
import Bag
-import Util ( zipEqual )
import Outputable
\end{code}
%************************************************************************
\begin{code}
--- 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
+-- This is the right function to pass to tcPat when
+-- we're looking at a lambda-bound pattern,
+-- so there's no polymorphic guy to worry about
+tcMonoPatBndr binder_name pat_ty = returnTc (mkLocalId binder_name pat_ty)
\end{code}
%************************************************************************
\begin{code}
-tcPat :: (Name -> TcType -> TcM s TcId) -- How to construct a suitable (monomorphic)
+tcPat :: (Name -> TcType -> TcM TcId) -- How to construct a suitable (monomorphic)
-- Id for variables found in the pattern
-- The TcType is the expected type, see note below
-> RenamedPat
-- INVARIANT: if it is, the foralls will always be visible,
-- not hidden inside a mutable type variable
- -> TcM s (TcPat,
+ -> TcM (TcPat,
LIE, -- Required by n+k and literal pats
Bag TcTyVar, -- TyVars bound by the pattern
-- These are just the existentially-bound ones.
%************************************************************************
\begin{code}
+tcPat tc_bndr pat@(TypePatIn ty) pat_ty
+ = failWithTc (badTypePat pat)
+
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 tc_bndr WildPatIn pat_ty
= returnTc (WildPat pat_ty, emptyLIE, emptyBag, emptyBag, emptyLIE)
-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 (HsIntPrim i)) = LitPatIn (HsIntPrim (-i))
- negate_lit (LitPatIn (HsFrac f)) = LitPatIn (HsFrac (-f))
- negate_lit (LitPatIn (HsFloatPrim f)) = LitPatIn (HsFloatPrim (-f))
- negate_lit (LitPatIn (HsDoublePrim f)) = LitPatIn (HsDoublePrim (-f))
- negate_lit _ = panic "TcPat:negate_pat"
-
tcPat tc_bndr (ParPatIn parend_pat) pat_ty
= tcPat tc_bndr parend_pat pat_ty
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 tc_bndr pat_in@(TuplePatIn pats boxed) pat_ty
+tcPat tc_bndr pat_in@(TuplePatIn pats boxity) pat_ty
= tcAddErrCtxt (patCtxt pat_in) $
- (if boxed
- then unifyTupleTy arity pat_ty
- else unifyUnboxedTupleTy arity pat_ty) `thenTc` \ arg_tys ->
-
- tcPats tc_bndr pats arg_tys `thenTc` \ (pats', lie_req, tvs, ids, lie_avail) ->
+ unifyTupleTy boxity arity pat_ty `thenTc` \ arg_tys ->
+ tcPats tc_bndr pats arg_tys `thenTc` \ (pats', lie_req, tvs, ids, lie_avail) ->
-- possibly do the "make all tuple-pats irrefutable" test:
let
- unmangled_result = TuplePat pats' boxed
+ unmangled_result = TuplePat pats' boxity
-- Under flag control turn a pattern (x,y,z) into ~(x,y,z)
-- so that we can experiment with lazy tuple-matching.
-- it was easy to do.
possibly_mangled_result
- | opt_IrrefutableTuples && boxed = LazyPat unmangled_result
- | otherwise = unmangled_result
+ | opt_IrrefutableTuples && isBoxed boxity = LazyPat unmangled_result
+ | otherwise = unmangled_result
in
returnTc (possibly_mangled_result, lie_req, tvs, ids, lie_avail)
where
-- Check the constructor itself
tcConstructor pat name pat_ty `thenTc` \ (data_con, ex_tvs, dicts, lie_avail1, arg_tys) ->
let
- field_tys = zipEqual "tcPat"
- (map fieldLabelName (dataConFieldLabels data_con))
- arg_tys
+ -- Don't use zipEqual! If the constructor isn't really a record, then
+ -- dataConFieldLabels will be empty (and each field in the pattern
+ -- will generate an error below).
+ field_tys = zip (map fieldLabelName (dataConFieldLabels data_con))
+ arg_tys
in
-- Check the fields
-- If foo isn't one of R's fields, we don't want to crash when
-- typechecking the "a+b".
[] -> addErrTc (badFieldCon name field_label) `thenNF_Tc_`
- newTyVarTy boxedTypeKind `thenNF_Tc_`
+ newTyVarTy liftedTypeKind `thenNF_Tc_`
returnTc (error "Bogus selector Id", pat_ty)
-- The normal case, when the field comes from the right constructor
(pat_ty : extras) ->
ASSERT( null extras )
- tcLookupValue field_label `thenNF_Tc` \ sel_id ->
+ tcLookupGlobalId field_label `thenNF_Tc` \ sel_id ->
returnTc (sel_id, pat_ty)
) `thenTc` \ (sel_id, pat_ty) ->
%************************************************************************
%* *
-\subsection{Non-overloaded literals}
+\subsection{Literals}
%* *
%************************************************************************
\begin{code}
-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
+tcPat tc_bndr (LitPatIn lit@(HsLitLit s _)) pat_ty
-- cf tcExpr on LitLits
- = tcLookupClassByKey cCallableClassKey `thenNF_Tc` \ cCallableClass ->
+ = tcLookupClass cCallableClassName `thenNF_Tc` \ cCallableClass ->
newDicts (LitLitOrigin (_UNPK_ s))
- [mkClassPred cCallableClass [pat_ty]] `thenNF_Tc` \ (dicts, _) ->
- returnTc (LitPat lit pat_ty, dicts, emptyBag, emptyBag, emptyLIE)
+ [mkClassPred cCallableClass [pat_ty]] `thenNF_Tc` \ dicts ->
+ returnTc (LitPat (HsLitLit s pat_ty) pat_ty, mkLIE dicts, emptyBag, emptyBag, emptyLIE)
+
+tcPat tc_bndr pat@(LitPatIn lit@(HsString _)) pat_ty
+ = unifyTauTy pat_ty stringTy `thenTc_`
+ tcLookupGlobalId eqStringName `thenNF_Tc` \ eq_id ->
+ returnTc (NPat lit stringTy (HsVar eq_id `HsApp` HsLit lit),
+ emptyLIE, emptyBag, emptyBag, emptyLIE)
+
+tcPat tc_bndr (LitPatIn simple_lit) pat_ty
+ = unifyTauTy pat_ty (simpleHsLitTy simple_lit) `thenTc_`
+ returnTc (LitPat simple_lit pat_ty, emptyLIE, emptyBag, emptyBag, emptyLIE)
+
+tcPat tc_bndr pat@(NPatIn over_lit) pat_ty
+ = newOverloadedLit (PatOrigin pat) over_lit pat_ty `thenNF_Tc` \ (over_lit_expr, lie1) ->
+ tcLookupGlobalId eqName `thenNF_Tc` \ eq_sel_id ->
+ newMethod origin eq_sel_id [pat_ty] `thenNF_Tc` \ eq ->
+
+ returnTc (NPat lit' pat_ty (HsApp (HsVar (instToId eq)) over_lit_expr),
+ lie1 `plusLIE` unitLIE eq,
+ emptyBag, emptyBag, emptyLIE)
+ where
+ origin = PatOrigin pat
+ lit' = case over_lit of
+ HsIntegral i -> HsInteger i
+ HsFractional f -> HsRat f pat_ty
\end{code}
%************************************************************************
%* *
-\subsection{Overloaded patterns: int literals and \tr{n+k} patterns}
+\subsection{n+k patterns}
%* *
%************************************************************************
\begin{code}
-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) ->
- let
- comp_op = HsApp (HsVar eq_id) (HsLitOut lit stringTy)
- in
- returnTc (NPat lit stringTy comp_op, lie, emptyBag, emptyBag, emptyLIE)
-
-
-tcPat tc_bndr pat@(LitPatIn lit@(HsInt i)) pat_ty
- = tcOverloadedLitPat pat lit (OverloadedIntegral i) pat_ty
-
-tcPat tc_bndr pat@(LitPatIn lit@(HsFrac f)) pat_ty
- = tcOverloadedLitPat pat lit (OverloadedFractional f) pat_ty
-
-
-tcPat tc_bndr pat@(NPlusKPatIn name lit@(HsInt i)) pat_ty
+tcPat tc_bndr pat@(NPlusKPatIn name lit@(HsIntegral 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 ->
-
- newOverloadedLit origin
- (OverloadedIntegral i) pat_ty `thenNF_Tc` \ (over_lit_expr, lie1) ->
-
- newMethod origin ge_sel_id [pat_ty] `thenNF_Tc` \ (lie2, ge_id) ->
- newMethod origin minus_sel_id [pat_ty] `thenNF_Tc` \ (lie3, minus_id) ->
-
- returnTc (NPlusKPat bndr_id lit pat_ty
- (SectionR (HsVar ge_id) over_lit_expr)
- (SectionR (HsVar minus_id) over_lit_expr),
- lie1 `plusLIE` lie2 `plusLIE` lie3,
+ -- The '-' part is re-mappable syntax
+ tcLookupSyntaxId minusName `thenNF_Tc` \ minus_sel_id ->
+ tcLookupGlobalId geName `thenNF_Tc` \ ge_sel_id ->
+ newOverloadedLit origin lit pat_ty `thenNF_Tc` \ (over_lit_expr, lie1) ->
+ newMethod origin ge_sel_id [pat_ty] `thenNF_Tc` \ ge ->
+ newMethod origin minus_sel_id [pat_ty] `thenNF_Tc` \ minus ->
+
+ returnTc (NPlusKPat bndr_id i pat_ty
+ (SectionR (HsVar (instToId ge)) over_lit_expr)
+ (SectionR (HsVar (instToId minus)) over_lit_expr),
+ lie1 `plusLIE` mkLIE [ge,minus],
emptyBag, unitBag (name, bndr_id), emptyLIE)
where
origin = PatOrigin pat
-
-tcPat tc_bndr (NPlusKPatIn pat other) pat_ty
- = panic "TcPat:NPlusKPat: not an HsInt literal"
\end{code}
%************************************************************************
Helper functions
\begin{code}
-tcPats :: (Name -> TcType -> TcM s TcId) -- How to deal with variables
+tcPats :: (Name -> TcType -> TcM TcId) -- How to deal with variables
-> [RenamedPat] -> [TcType] -- Excess 'expected types' discarded
- -> TcM s ([TcPat],
+ -> TcM ([TcPat],
LIE, -- Required by n+k and literal pats
Bag TcTyVar,
Bag (Name, TcId), -- Ids bound by the pattern
------------------------------------------------------
\begin{code}
-tcSimpleLitPat lit lit_ty pat_ty
- = unifyTauTy pat_ty lit_ty `thenTc_`
- returnTc (LitPat lit lit_ty, emptyLIE, emptyBag, emptyBag, emptyLIE)
-
-
-tcOverloadedLitPat pat lit over_lit pat_ty
- = newOverloadedLit (PatOrigin pat) over_lit pat_ty `thenNF_Tc` \ (over_lit_expr, lie1) ->
- tcLookupValueByKey eqClassOpKey `thenNF_Tc` \ eq_sel_id ->
- newMethod origin eq_sel_id [pat_ty] `thenNF_Tc` \ (lie2, eq_id) ->
-
- returnTc (NPat lit pat_ty (HsApp (HsVar eq_id)
- over_lit_expr),
- lie1 `plusLIE` lie2,
- emptyBag, emptyBag, emptyLIE)
- where
- origin = PatOrigin pat
+simpleHsLitTy :: HsLit -> TcType
+simpleHsLitTy (HsCharPrim c) = charPrimTy
+simpleHsLitTy (HsStringPrim s) = addrPrimTy
+simpleHsLitTy (HsInt i) = intTy
+simpleHsLitTy (HsInteger i) = integerTy
+simpleHsLitTy (HsIntPrim i) = intPrimTy
+simpleHsLitTy (HsFloatPrim f) = floatPrimTy
+simpleHsLitTy (HsDoublePrim d) = doublePrimTy
+simpleHsLitTy (HsChar c) = charTy
+simpleHsLitTy (HsString str) = stringTy
\end{code}
+
------------------------------------------------------
\begin{code}
tcConstructor pat con_name pat_ty
= -- Check that it's a constructor
- tcLookupValue con_name `thenNF_Tc` \ con_id ->
- case isDataConWrapId_maybe con_id of {
- Nothing -> failWithTc (badCon con_id);
- Just data_con ->
+ tcLookupDataCon con_name `thenNF_Tc` \ data_con ->
-- Instantiate it
let
- (tvs, theta, ex_tvs, ex_theta, arg_tys, tycon) = dataConSig data_con
+ (tvs, _, ex_tvs, ex_theta, arg_tys, tycon) = dataConSig data_con
-- Ignore the theta; overloaded constructors only
-- behave differently when called, not when used for
-- matching.
in
tcInstTyVars (ex_tvs ++ tvs) `thenNF_Tc` \ (all_tvs', ty_args', tenv) ->
let
- ex_theta' = substClasses tenv ex_theta
+ 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'
result_ty = mkTyConApp tycon (drop n_ex_tvs ty_args')
in
- newClassDicts (PatOrigin pat) ex_theta' `thenNF_Tc` \ (lie_avail, dicts) ->
+ newDicts (PatOrigin pat) ex_theta' `thenNF_Tc` \ dicts ->
-- Check overall type matches
unifyTauTy pat_ty result_ty `thenTc_`
- returnTc (data_con, ex_tvs', dicts, lie_avail, arg_tys')
- }
+ returnTc (data_con, ex_tvs', map instToId dicts, mkLIE dicts, arg_tys')
\end{code}
------------------------------------------------------
patCtxt pat = hang (ptext SLIT("In the pattern:"))
4 (ppr pat)
-recordLabel field_label
- = hang (hcat [ptext SLIT("When matching record field"), ppr field_label])
- 4 (hcat [ptext SLIT("with its immediately enclosing constructor")])
-
-recordRhs field_label pat
- = hang (ptext SLIT("In the record field pattern"))
- 4 (sep [ppr field_label, char '=', ppr pat])
-
badFieldCon :: Name -> Name -> SDoc
badFieldCon con field
= hsep [ptext SLIT("Constructor") <+> quotes (ppr con),
polyPatSig sig_ty
= hang (ptext SLIT("Illegal polymorphic type signature in pattern:"))
4 (ppr sig_ty)
+
+badTypePat pat = ptext SLIT("Illegal type pattern") <+> ppr pat
\end{code}
projects / ghc-hetmet.git / blobdiff