\section[TcExpr]{Typecheck an expression}
\begin{code}
-module TcExpr ( tcCheckSigma, tcCheckRho, tcInferRho, tcMonoExpr ) where
+module TcExpr ( tcCheckSigma, tcCheckRho, tcInferRho,
+ tcMonoExpr, tcExpr, tcSyntaxOp
+ ) where
#include "HsVersions.h"
#ifdef GHCI /* Only if bootstrapped */
import {-# SOURCE #-} TcSplice( tcSpliceExpr, tcBracket )
+import HsSyn ( nlHsVar )
import Id ( Id )
+import Name ( isExternalName )
import TcType ( isTauTy )
import TcEnv ( checkWellStaged )
import HsSyn ( nlHsApp )
#endif
import HsSyn ( HsExpr(..), LHsExpr, HsLit(..), ArithSeqInfo(..), recBindFields,
- HsMatchContext(..), HsRecordBinds, mkHsApp, nlHsVar )
+ HsMatchContext(..), HsRecordBinds, mkHsApp )
import TcHsSyn ( hsLitType, (<$>) )
import TcRnMonad
-import TcUnify ( Expected(..), tcInfer, zapExpectedType, zapExpectedTo, tcSubExp, tcGen,
- unifyFunTys, zapToListTy, zapToTyConApp, readExpectedType )
+import TcUnify ( Expected(..), tcInfer, zapExpectedType, zapExpectedTo,
+ tcSubExp, tcGen, tcSub,
+ unifyFunTys, zapToListTy, zapToTyConApp )
import BasicTypes ( isMarkedStrict )
-import Inst ( InstOrigin(..),
- newOverloadedLit, newMethodFromName, newIPDict,
+import Inst ( tcOverloadedLit, newMethodFromName, newIPDict,
newDicts, newMethodWithGivenTy, tcInstStupidTheta, tcInstCall )
import TcBinds ( tcBindsAndThen )
import TcEnv ( tcLookup, tcLookupId, checkProcLevel,
import TcArrows ( tcProc )
import TcMatches ( tcMatchesCase, tcMatchLambda, tcDoStmts, tcThingWithSig, TcMatchCtxt(..) )
import TcHsType ( tcHsSigType, UserTypeCtxt(..) )
-import TcPat ( badFieldCon )
-import TcMType ( tcInstTyVars, tcInstType, newTyFlexiVarTy, zonkTcType, readMetaTyVar )
-import TcType ( Type, TcTyVar, TcType, TcSigmaType, TcRhoType, MetaDetails(..),
+import TcPat ( badFieldCon, refineTyVars )
+import TcMType ( tcInstTyVars, tcInstType, newTyFlexiVarTy, zonkTcType )
+import TcType ( Type, TcTyVar, TcType, TcSigmaType, TcRhoType,
tcSplitFunTys, tcSplitTyConApp, mkTyVarTys,
isSigmaTy, mkFunTy, mkTyConApp, tyVarsOfTypes, isLinearPred,
tcSplitSigmaTy, tidyOpenType
import Kind ( openTypeKind, liftedTypeKind, argTypeKind )
import Id ( idType, recordSelectorFieldLabel, isRecordSelector )
-import DataCon ( DataCon, dataConFieldLabels, dataConStrictMarks, dataConWrapId )
+import DataCon ( DataCon, dataConFieldLabels, dataConStrictMarks,
+ dataConWrapId )
import Name ( Name )
import TyCon ( TyCon, FieldLabel, tyConTyVars, tyConStupidTheta,
tyConDataCons, tyConFields )
-import Type ( zipTopTvSubst, mkTopTvSubst, substTheta, substTy )
+import Type ( zipTopTvSubst, substTheta, substTy )
+import Var ( tyVarKind )
import VarSet ( emptyVarSet, elemVarSet )
import TysWiredIn ( boolTy, parrTyCon, tupleTyCon )
import PrelNames ( enumFromName, enumFromThenName,
enumFromToName, enumFromThenToName,
- enumFromToPName, enumFromThenToPName
+ enumFromToPName, enumFromThenToPName, negateName
)
import ListSetOps ( minusList )
-import CmdLineOpts
+import DynFlags
+import StaticFlags ( opt_NoMethodSharing )
import HscTypes ( TyThing(..) )
import SrcLoc ( Located(..), unLoc, getLoc )
import Util
-import Maybes ( catMaybes )
import Outputable
import FastString
tcInferRho :: LHsExpr Name -> TcM (LHsExpr TcId, TcRhoType)
tcInferRho (L loc (HsVar name)) = setSrcSpan loc $ do
- { (e,_,ty) <- tcId name; return (L loc e, ty)}
+ { (e,_,ty) <- tcId (OccurrenceOf name) name
+ ; return (L loc e, ty) }
tcInferRho expr = tcInfer (tcMonoExpr expr)
+
+tcSyntaxOp :: InstOrigin -> HsExpr Name -> TcType -> TcM (HsExpr TcId)
+-- Typecheck a syntax operator, checking that it has the specified type
+-- The operator is always a variable at this stage (i.e. renamer output)
+tcSyntaxOp orig (HsVar op) ty = do { (expr', _, id_ty) <- tcId orig op
+ ; co_fn <- tcSub ty id_ty
+ ; returnM (co_fn <$> expr') }
+tcSyntaxOp orig other ty = pprPanic "tcSyntaxOp" (ppr other)
\end{code}
-> TcM (LHsExpr TcId)
tcMonoExpr (L loc expr) res_ty
- = setSrcSpan loc (do { expr' <- tc_expr expr res_ty
+ = setSrcSpan loc (do { expr' <- tcExpr expr res_ty
; return (L loc expr') })
-tc_expr :: HsExpr Name -> Expected TcRhoType -> TcM (HsExpr TcId)
-tc_expr (HsVar name) res_ty
- = do { (expr', _, id_ty) <- tcId name
+tcExpr :: HsExpr Name -> Expected TcRhoType -> TcM (HsExpr TcId)
+tcExpr (HsVar name) res_ty
+ = do { (expr', _, id_ty) <- tcId (OccurrenceOf name) name
; co_fn <- tcSubExp res_ty id_ty
; returnM (co_fn <$> expr') }
-tc_expr (HsIPVar ip) res_ty
+tcExpr (HsIPVar ip) res_ty
= -- Implicit parameters must have a *tau-type* not a
-- type scheme. We enforce this by creating a fresh
-- type variable as its type. (Because res_ty may not
%************************************************************************
\begin{code}
-tc_expr in_expr@(ExprWithTySig expr poly_ty) res_ty
+tcExpr in_expr@(ExprWithTySig expr poly_ty) res_ty
= addErrCtxt (exprCtxt in_expr) $
tcHsSigType ExprSigCtxt poly_ty `thenM` \ sig_tc_ty ->
tcThingWithSig sig_tc_ty (tcCheckRho expr) res_ty `thenM` \ (co_fn, expr') ->
returnM (co_fn <$> ExprWithTySigOut expr' poly_ty)
-tc_expr (HsType ty) res_ty
+tcExpr (HsType ty) res_ty
= failWithTc (text "Can't handle type argument:" <+> ppr ty)
-- This is the syntax for type applications that I was planning
-- but there are difficulties (e.g. what order for type args)
%************************************************************************
\begin{code}
-tc_expr (HsPar expr) res_ty = tcMonoExpr expr res_ty `thenM` \ expr' ->
+tcExpr (HsPar expr) res_ty = tcMonoExpr expr res_ty `thenM` \ expr' ->
returnM (HsPar expr')
-tc_expr (HsSCC lbl expr) res_ty = tcMonoExpr expr res_ty `thenM` \ expr' ->
+tcExpr (HsSCC lbl expr) res_ty = tcMonoExpr expr res_ty `thenM` \ expr' ->
returnM (HsSCC lbl expr')
-tc_expr (HsCoreAnn lbl expr) res_ty = tcMonoExpr expr res_ty `thenM` \ expr' -> -- hdaume: core annotation
+tcExpr (HsCoreAnn lbl expr) res_ty = tcMonoExpr expr res_ty `thenM` \ expr' -> -- hdaume: core annotation
returnM (HsCoreAnn lbl expr')
-tc_expr (HsLit lit) res_ty = tcLit lit res_ty
+tcExpr (HsLit lit) res_ty = tcLit lit res_ty
-tc_expr (HsOverLit lit) res_ty
+tcExpr (HsOverLit lit) res_ty
= zapExpectedType res_ty liftedTypeKind `thenM` \ res_ty' ->
- newOverloadedLit (LiteralOrigin lit) lit res_ty' `thenM` \ lit_expr ->
- returnM (unLoc lit_expr) -- ToDo: nasty unLoc
-
-tc_expr (NegApp expr neg_name) res_ty
- = tc_expr (HsApp (nlHsVar neg_name) expr) res_ty
- -- ToDo: use tcSyntaxName
-
-tc_expr (HsLam match) res_ty
+ -- Overloaded literals must have liftedTypeKind, because
+ -- we're instantiating an overloaded function here,
+ -- whereas res_ty might be openTypeKind. This was a bug in 6.2.2
+ tcOverloadedLit (LiteralOrigin lit) lit res_ty' `thenM` \ lit' ->
+ returnM (HsOverLit lit')
+
+tcExpr (NegApp expr neg_expr) res_ty
+ = do { res_ty' <- zapExpectedType res_ty liftedTypeKind
+ ; neg_expr' <- tcSyntaxOp (OccurrenceOf negateName) neg_expr
+ (mkFunTy res_ty' res_ty')
+ ; expr' <- tcCheckRho expr res_ty'
+ ; return (NegApp expr' neg_expr') }
+
+tcExpr (HsLam match) res_ty
= tcMatchLambda match res_ty `thenM` \ match' ->
returnM (HsLam match')
-tc_expr (HsApp e1 e2) res_ty
+tcExpr (HsApp e1 e2) res_ty
= tcApp e1 [e2] res_ty
\end{code}
-- or just
-- op e
-tc_expr in_expr@(SectionL arg1 op) res_ty
+tcExpr in_expr@(SectionL arg1 op) res_ty
= tcInferRho op `thenM` \ (op', op_ty) ->
unifyFunTys 2 op_ty {- two args -} `thenM` \ ([arg1_ty, arg2_ty], op_res_ty) ->
tcArg op (arg1, arg1_ty, 1) `thenM` \ arg1' ->
-- Right sections, equivalent to \ x -> x op expr, or
-- \ x -> op x expr
-tc_expr in_expr@(SectionR op arg2) res_ty
+tcExpr in_expr@(SectionR op arg2) res_ty
= tcInferRho op `thenM` \ (op', op_ty) ->
unifyFunTys 2 op_ty {- two args -} `thenM` \ ([arg1_ty, arg2_ty], op_res_ty) ->
tcArg op (arg2, arg2_ty, 2) `thenM` \ arg2' ->
-- equivalent to (op e1) e2:
-tc_expr in_expr@(OpApp arg1 op fix arg2) res_ty
+tcExpr in_expr@(OpApp arg1 op fix arg2) res_ty
= tcInferRho op `thenM` \ (op', op_ty) ->
unifyFunTys 2 op_ty {- two args -} `thenM` \ ([arg1_ty, arg2_ty], op_res_ty) ->
tcArg op (arg1, arg1_ty, 1) `thenM` \ arg1' ->
\end{code}
\begin{code}
-tc_expr (HsLet binds (L loc expr)) res_ty
+tcExpr (HsLet binds (L loc expr)) res_ty
= tcBindsAndThen
glue
binds -- Bindings to check
- (setSrcSpan loc $ tc_expr expr res_ty)
+ (setSrcSpan loc $ tcExpr expr res_ty)
where
glue bind expr = HsLet [bind] (L loc expr)
-tc_expr in_expr@(HsCase scrut matches) exp_ty
+tcExpr in_expr@(HsCase scrut matches) exp_ty
= -- We used to typecheck the case alternatives first.
-- The case patterns tend to give good type info to use
-- when typechecking the scrutinee. For example
match_ctxt = MC { mc_what = CaseAlt,
mc_body = tcMonoExpr }
-tc_expr (HsIf pred b1 b2) res_ty
- = addErrCtxt (predCtxt pred) (
- tcCheckRho pred boolTy ) `thenM` \ pred' ->
+tcExpr (HsIf pred b1 b2) res_ty
+ = addErrCtxt (predCtxt pred)
+ (tcCheckRho pred boolTy) `thenM` \ pred' ->
zapExpectedType res_ty openTypeKind `thenM` \ res_ty' ->
-- C.f. the call to zapToType in TcMatches.tcMatches
tcCheckRho b2 res_ty' `thenM` \ b2' ->
returnM (HsIf pred' b1' b2')
-tc_expr (HsDo do_or_lc stmts method_names _) res_ty
- = zapExpectedType res_ty liftedTypeKind `thenM` \ res_ty' ->
- -- All comprehensions yield a monotype of kind *
- tcDoStmts do_or_lc stmts method_names res_ty' `thenM` \ (stmts', methods') ->
- returnM (HsDo do_or_lc stmts' methods' res_ty')
+tcExpr (HsDo do_or_lc stmts body _) res_ty
+ = tcDoStmts do_or_lc stmts body res_ty
-tc_expr in_expr@(ExplicitList _ exprs) res_ty -- Non-empty list
+tcExpr in_expr@(ExplicitList _ exprs) res_ty -- Non-empty list
= zapToListTy res_ty `thenM` \ elt_ty ->
mappM (tc_elt elt_ty) exprs `thenM` \ exprs' ->
returnM (ExplicitList elt_ty exprs')
= addErrCtxt (listCtxt expr) $
tcCheckRho expr elt_ty
-tc_expr in_expr@(ExplicitPArr _ exprs) res_ty -- maybe empty
+tcExpr in_expr@(ExplicitPArr _ exprs) res_ty -- maybe empty
= do { [elt_ty] <- zapToTyConApp parrTyCon res_ty
; exprs' <- mappM (tc_elt elt_ty) exprs
; return (ExplicitPArr elt_ty exprs') }
tc_elt elt_ty expr
= addErrCtxt (parrCtxt expr) (tcCheckRho expr elt_ty)
-tc_expr (ExplicitTuple exprs boxity) res_ty
+tcExpr (ExplicitTuple exprs boxity) res_ty
= do { arg_tys <- zapToTyConApp (tupleTyCon boxity (length exprs)) res_ty
; exprs' <- tcCheckRhos exprs arg_tys
; return (ExplicitTuple exprs' boxity) }
-tc_expr (HsProc pat cmd) res_ty
+tcExpr (HsProc pat cmd) res_ty
= tcProc pat cmd res_ty `thenM` \ (pat', cmd') ->
returnM (HsProc pat' cmd')
-tc_expr e@(HsArrApp _ _ _ _ _) _
+tcExpr e@(HsArrApp _ _ _ _ _) _
= failWithTc (vcat [ptext SLIT("The arrow command"), nest 2 (ppr e),
ptext SLIT("was found where an expression was expected")])
-tc_expr e@(HsArrForm _ _ _) _
+tcExpr e@(HsArrForm _ _ _) _
= failWithTc (vcat [ptext SLIT("The arrow command"), nest 2 (ppr e),
ptext SLIT("was found where an expression was expected")])
\end{code}
%************************************************************************
\begin{code}
-tc_expr expr@(RecordCon con@(L loc con_name) rbinds) res_ty
+tcExpr expr@(RecordCon con@(L loc con_name) _ rbinds) res_ty
= addErrCtxt (recordConCtxt expr) $
- addLocM tcId con `thenM` \ (con_expr, _, con_tau) ->
+ addLocM (tcId (OccurrenceOf con_name)) con `thenM` \ (con_expr, _, con_tau) ->
let
(_, record_ty) = tcSplitFunTys con_tau
(tycon, ty_args) = tcSplitTyConApp record_ty
-- Check for missing fields
checkMissingFields data_con rbinds `thenM_`
- getSrcSpanM `thenM` \ loc ->
- returnM (RecordConOut data_con (L loc con_expr) rbinds')
+ returnM (RecordCon (L loc (dataConWrapId data_con)) con_expr rbinds')
-- The main complication with RecordUpd is that we need to explicitly
-- handle the *non-updated* fields. Consider:
--
-- All this is done in STEP 4 below.
-tc_expr expr@(RecordUpd record_expr rbinds) res_ty
+tcExpr expr@(RecordUpd record_expr rbinds _ _) res_ty
= addErrCtxt (recordUpdCtxt expr) $
-- STEP 0
non_upd_field_lbls = concat relevant_field_lbls_s `minusList` upd_field_lbls
common_tyvars = tyVarsOfTypes [ty | (fld,ty,_) <- tyConFields tycon,
fld `elem` non_upd_field_lbls]
+ is_common_tv tv = tv `elemVarSet` common_tyvars
- mk_inst_ty tyvar result_inst_ty
- | tyvar `elemVarSet` common_tyvars = returnM result_inst_ty -- Same as result type
--- gaw 2004 FIX?
- | otherwise = newTyFlexiVarTy liftedTypeKind -- Fresh type
+ mk_inst_ty tv result_inst_ty
+ | is_common_tv tv = returnM result_inst_ty -- Same as result type
+ | otherwise = newTyFlexiVarTy (tyVarKind tv) -- Fresh type, of correct kind
in
zipWithM mk_inst_ty tycon_tyvars result_inst_tys `thenM` \ inst_tys ->
extendLIEs dicts `thenM_`
-- Phew!
- returnM (RecordUpdOut record_expr' record_ty result_record_ty rbinds')
+ returnM (RecordUpd record_expr' rbinds' record_ty result_record_ty)
\end{code}
%************************************************************************
\begin{code}
-tc_expr (ArithSeqIn seq@(From expr)) res_ty
+tcExpr (ArithSeq _ seq@(From expr)) res_ty
= zapToListTy res_ty `thenM` \ elt_ty ->
tcCheckRho expr elt_ty `thenM` \ expr' ->
newMethodFromName (ArithSeqOrigin seq)
elt_ty enumFromName `thenM` \ enum_from ->
- returnM (ArithSeqOut (nlHsVar enum_from) (From expr'))
+ returnM (ArithSeq (HsVar enum_from) (From expr'))
-tc_expr in_expr@(ArithSeqIn seq@(FromThen expr1 expr2)) res_ty
+tcExpr in_expr@(ArithSeq _ seq@(FromThen expr1 expr2)) res_ty
= addErrCtxt (arithSeqCtxt in_expr) $
zapToListTy res_ty `thenM` \ elt_ty ->
tcCheckRho expr1 elt_ty `thenM` \ expr1' ->
newMethodFromName (ArithSeqOrigin seq)
elt_ty enumFromThenName `thenM` \ enum_from_then ->
- returnM (ArithSeqOut (nlHsVar enum_from_then) (FromThen expr1' expr2'))
+ returnM (ArithSeq (HsVar enum_from_then) (FromThen expr1' expr2'))
-tc_expr in_expr@(ArithSeqIn seq@(FromTo expr1 expr2)) res_ty
+tcExpr in_expr@(ArithSeq _ seq@(FromTo expr1 expr2)) res_ty
= addErrCtxt (arithSeqCtxt in_expr) $
zapToListTy res_ty `thenM` \ elt_ty ->
tcCheckRho expr1 elt_ty `thenM` \ expr1' ->
newMethodFromName (ArithSeqOrigin seq)
elt_ty enumFromToName `thenM` \ enum_from_to ->
- returnM (ArithSeqOut (nlHsVar enum_from_to) (FromTo expr1' expr2'))
+ returnM (ArithSeq (HsVar enum_from_to) (FromTo expr1' expr2'))
-tc_expr in_expr@(ArithSeqIn seq@(FromThenTo expr1 expr2 expr3)) res_ty
+tcExpr in_expr@(ArithSeq _ seq@(FromThenTo expr1 expr2 expr3)) res_ty
= addErrCtxt (arithSeqCtxt in_expr) $
zapToListTy res_ty `thenM` \ elt_ty ->
tcCheckRho expr1 elt_ty `thenM` \ expr1' ->
newMethodFromName (ArithSeqOrigin seq)
elt_ty enumFromThenToName `thenM` \ eft ->
- returnM (ArithSeqOut (nlHsVar eft) (FromThenTo expr1' expr2' expr3'))
+ returnM (ArithSeq (HsVar eft) (FromThenTo expr1' expr2' expr3'))
-tc_expr in_expr@(PArrSeqIn seq@(FromTo expr1 expr2)) res_ty
+tcExpr in_expr@(PArrSeq _ seq@(FromTo expr1 expr2)) res_ty
= addErrCtxt (parrSeqCtxt in_expr) $
zapToTyConApp parrTyCon res_ty `thenM` \ [elt_ty] ->
tcCheckRho expr1 elt_ty `thenM` \ expr1' ->
newMethodFromName (PArrSeqOrigin seq)
elt_ty enumFromToPName `thenM` \ enum_from_to ->
- returnM (PArrSeqOut (nlHsVar enum_from_to) (FromTo expr1' expr2'))
+ returnM (PArrSeq (HsVar enum_from_to) (FromTo expr1' expr2'))
-tc_expr in_expr@(PArrSeqIn seq@(FromThenTo expr1 expr2 expr3)) res_ty
+tcExpr in_expr@(PArrSeq _ seq@(FromThenTo expr1 expr2 expr3)) res_ty
= addErrCtxt (parrSeqCtxt in_expr) $
zapToTyConApp parrTyCon res_ty `thenM` \ [elt_ty] ->
tcCheckRho expr1 elt_ty `thenM` \ expr1' ->
newMethodFromName (PArrSeqOrigin seq)
elt_ty enumFromThenToPName `thenM` \ eft ->
- returnM (PArrSeqOut (nlHsVar eft) (FromThenTo expr1' expr2' expr3'))
+ returnM (PArrSeq (HsVar eft) (FromThenTo expr1' expr2' expr3'))
-tc_expr (PArrSeqIn _) _
+tcExpr (PArrSeq _ _) _
= panic "TcExpr.tcMonoExpr: Infinite parallel array!"
-- the parser shouldn't have generated it and the renamer shouldn't have
-- let it through
\begin{code}
#ifdef GHCI /* Only if bootstrapped */
-- Rename excludes these cases otherwise
-tc_expr (HsSpliceE splice) res_ty = tcSpliceExpr splice res_ty
-tc_expr (HsBracket brack) res_ty = do { e <- tcBracket brack res_ty
+tcExpr (HsSpliceE splice) res_ty = tcSpliceExpr splice res_ty
+tcExpr (HsBracket brack) res_ty = do { e <- tcBracket brack res_ty
; return (unLoc e) }
#endif /* GHCI */
\end{code}
%************************************************************************
\begin{code}
-tc_expr other _ = pprPanic "tcMonoExpr" (ppr other)
+tcExpr other _ = pprPanic "tcMonoExpr" (ppr other)
\end{code}
Infer _ -> do -- Type check args first, then
-- refine result type, then do tcResult
{ the_app' <- tcArgs fun fun' args expected_arg_tys
- ; actual_res_ty' <- refineResultTy fun_tvs actual_res_ty
+ ; subst <- refineTyVars fun_tvs
+ ; let actual_res_ty' = substTy subst actual_res_ty
; co_fn <- tcResult fun args res_ty actual_res_ty'
; traceTc (text "tcApp: infer" <+> vcat [ppr fun <+> ppr args, ppr the_app',
ppr actual_res_ty, ppr actual_res_ty'])
-- If the function isn't simple, infer its type, and return no
-- type variables
tcFun (L loc (HsVar f)) = setSrcSpan loc $ do
- { (fun', tvs, fun_tau) <- tcId f
+ { (fun', tvs, fun_tau) <- tcId (OccurrenceOf f) f
; return (L loc fun', tvs, fun_tau) }
tcFun fun = do { (fun', fun_tau) <- tcInfer (tcMonoExpr fun)
; return (fun', [], fun_tau) }
| otherwise = appCtxt fun args
in
returnM (env2, message)
-
-----------------
-refineResultTy :: [TcTyVar] -- Newly instantiated meta-tyvars of the function
- -> TcType -- Result type, instantiated with those tyvars
- -> TcM TcType -- Refined result type
--- De-wobblify the result type, by taking account what we learned
--- from type-checking the arguments. Just one level of de-wobblification
--- though. What a hack!
-refineResultTy tvs res_ty
- = do { mb_prs <- mapM mk_pr tvs
- ; let subst = mkTopTvSubst (catMaybes mb_prs)
- ; return (substTy subst res_ty) }
- where
- mk_pr tv = do { details <- readMetaTyVar tv
- ; case details of
- Indirect ty -> return (Just (tv,ty))
- other -> return Nothing
- }
\end{code}
b) perhaps fewer separated lambdas
\begin{code}
-tcId :: Name -> TcM (HsExpr TcId, [TcTyVar], TcRhoType)
+tcId :: InstOrigin -> Name -> TcM (HsExpr TcId, [TcTyVar], TcRhoType)
-- Return the type variables at which the function
-- is instantiated, as well as the translated variable and its type
-tcId name -- Look up the Id and instantiate its type
- = tcLookup name `thenM` \ thing ->
+tcId orig id_name -- Look up the Id and instantiate its type
+ = tcLookup id_name `thenM` \ thing ->
case thing of {
- AGlobal (AnId id) -> instantiate id
- -- A global cannot possibly be ill-staged
- -- nor does it need the 'lifting' treatment
-
- ; AGlobal (ADataCon con) -- Similar, but instantiate the stupid theta too
+ AGlobal (ADataCon con) -- Similar, but instantiate the stupid theta too
-> do { (expr, tvs, tau) <- instantiate (dataConWrapId con)
; tcInstStupidTheta con (mkTyVarTys tvs)
-- Remember to chuck in the constraints from the "silly context"
; return (expr, tvs, tau) }
+ ; AGlobal (AnId id) -> instantiate id
+ -- A global cannot possibly be ill-staged
+ -- nor does it need the 'lifting' treatment
+
; ATcId id th_level proc_level
-> do { checkProcLevel id proc_level
; tc_local_id id th_level }
- ; other -> pprPanic "tcId" (ppr name $$ ppr thing)
+ ; other -> failWithTc (ppr other <+> ptext SLIT("used where a value identifer was expected"))
}
where
case use_stage of
Brack use_lvl ps_var lie_var
| use_lvl > th_bind_lvl
- -> -- E.g. \x -> [| h x |]
- -- We must behave as if the reference to x was
- -- h $(lift x)
- -- We use 'x' itself as the splice proxy, used by
- -- the desugarer to stitch it all back together.
- -- If 'x' occurs many times we may get many identical
- -- bindings of the same splice proxy, but that doesn't
- -- matter, although it's a mite untidy.
- let
- id_ty = idType id
- in
- checkTc (isTauTy id_ty) (polySpliceErr id) `thenM_`
- -- If x is polymorphic, its occurrence sites might
- -- have different instantiations, so we can't use plain
- -- 'x' as the splice proxy name. I don't know how to
- -- solve this, and it's probably unimportant, so I'm
- -- just going to flag an error for now
-
- setLIEVar lie_var (
- newMethodFromName orig id_ty DsMeta.liftName `thenM` \ lift ->
- -- Put the 'lift' constraint into the right LIE
-
- -- Update the pending splices
- readMutVar ps_var `thenM` \ ps ->
- writeMutVar ps_var ((name, nlHsApp (nlHsVar lift) (nlHsVar id)) : ps) `thenM_`
-
- returnM (HsVar id, [], id_ty))
+ -> if isExternalName id_name then
+ -- Top-level identifiers in this module,
+ -- (which have External Names)
+ -- are just like the imported case:
+ -- no need for the 'lifting' treatment
+ -- E.g. this is fine:
+ -- f x = x
+ -- g y = [| f 3 |]
+ -- But we do need to put f into the keep-alive
+ -- set, because after desugaring the code will
+ -- only mention f's *name*, not f itself.
+ keepAliveTc id_name `thenM_`
+ instantiate id
+
+ else -- Nested identifiers, such as 'x' in
+ -- E.g. \x -> [| h x |]
+ -- We must behave as if the reference to x was
+ -- h $(lift x)
+ -- We use 'x' itself as the splice proxy, used by
+ -- the desugarer to stitch it all back together.
+ -- If 'x' occurs many times we may get many identical
+ -- bindings of the same splice proxy, but that doesn't
+ -- matter, although it's a mite untidy.
+ let
+ id_ty = idType id
+ in
+ checkTc (isTauTy id_ty) (polySpliceErr id) `thenM_`
+ -- If x is polymorphic, its occurrence sites might
+ -- have different instantiations, so we can't use plain
+ -- 'x' as the splice proxy name. I don't know how to
+ -- solve this, and it's probably unimportant, so I'm
+ -- just going to flag an error for now
+
+ setLIEVar lie_var (
+ newMethodFromName orig id_ty DsMeta.liftName `thenM` \ lift ->
+ -- Put the 'lift' constraint into the right LIE
+
+ -- Update the pending splices
+ readMutVar ps_var `thenM` \ ps ->
+ writeMutVar ps_var ((id_name, nlHsApp (nlHsVar lift) (nlHsVar id)) : ps) `thenM_`
+
+ returnM (HsVar id, [], id_ty))
other ->
checkWellStaged (quotes (ppr id)) th_bind_lvl use_stage `thenM_`
| otherwise = case tcSplitSigmaTy fun_ty of
(_,[],_) -> False -- Not overloaded
(_,theta,_) -> not (any isLinearPred theta)
-
- orig = OccurrenceOf name
\end{code}
%************************************************************************
projects / ghc-hetmet.git / blobdiff