%
-% (c) The GRASP/AQUA Project, Glasgow University, 1992-1995
+% (c) The GRASP/AQUA Project, Glasgow University, 1992-1998
%
-\section[TcExpr]{TcExpr}
+\section[TcExpr]{Typecheck an expression}
\begin{code}
+module TcExpr ( tcExpr, tcExpr_id, tcMonoExpr ) where
+
#include "HsVersions.h"
-module TcExpr (
- tcExpr
-#ifdef DPH
- , tcExprs
+#ifdef GHCI /* Only if bootstrapped */
+import {-# SOURCE #-} TcSplice( tcSpliceExpr )
+import TcEnv ( bracketOK, tcMetaTy )
+import TcSimplify ( tcSimplifyBracket )
+import PrelNames ( exprTyConName )
+import HsSyn ( HsBracket(..) )
#endif
- ) where
-import TcMonad -- typechecking monad machinery
-import TcMonadFns ( newPolyTyVarTy, newOpenTyVarTy,
- newDict, newMethod, newOverloadedLit,
- applyTcSubstAndCollectTyVars,
- mkIdsWithPolyTyVarTys
+import HsSyn ( HsExpr(..), HsLit(..), ArithSeqInfo(..),
+ mkMonoBind, recBindFields
)
-import AbsSyn -- the stuff being typechecked
-
-
-import AbsPrel ( intPrimTy, charPrimTy, doublePrimTy,
- floatPrimTy, addrPrimTy, addrTy,
- boolTy, charTy, stringTy, mkFunTy, mkListTy,
- mkTupleTy, mkPrimIoTy
-#ifdef DPH
- ,mkProcessorTy, mkPodTy,toPodId,
- processorClass,pidClass
-#endif {- Data Parallel Haskell -}
+import RnHsSyn ( RenamedHsExpr, RenamedRecordBinds )
+import TcHsSyn ( TcExpr, TcRecordBinds, hsLitType, mkHsDictApp, mkHsTyApp, mkHsLet )
+import TcRnMonad
+import TcUnify ( tcSubExp, tcGen, (<$>),
+ unifyTauTy, unifyFunTy, unifyListTy, unifyPArrTy,
+ unifyTupleTy )
+import BasicTypes ( RecFlag(..), isMarkedStrict )
+import Inst ( InstOrigin(..),
+ newOverloadedLit, newMethodFromName, newIPDict,
+ newDicts, newMethodWithGivenTy,
+ instToId, tcInstCall, tcInstDataCon
)
-import AbsUniType
-import E
-import CE ( lookupCE )
-
-import Errors
-import GenSpecEtc ( checkSigTyVars )
-import Id ( mkInstId, getIdUniType, Id )
-import Inst
-import LIE ( nullLIE, unitLIE, plusLIE, unMkLIE, mkLIE, LIE )
-import ListSetOps ( unionLists )
-import Maybes ( Maybe(..) )
-import TVE ( nullTVE, TVE(..) )
-import Spec ( specId, specTy )
-import TcBinds ( tcLocalBindsAndThen )
-import TcMatches ( tcMatchesCase, tcMatch )
-import TcPolyType ( tcPolyType )
-import TcQuals ( tcQuals )
-import TcSimplify ( tcSimplifyAndCheck, tcSimplifyRank2 )
-#ifdef DPH
-import TcParQuals
-#endif {- Data Parallel Haskell -}
-import Unify ( unifyTauTy, unifyTauTyList, unifyTauTyLists )
-import UniqFM ( emptyUFM ) -- profiling, pragmas only
-import Unique -- *Key stuff
-import Util
+import TcBinds ( tcBindsAndThen )
+import TcEnv ( tcLookupClass, tcLookupGlobal_maybe, tcLookupIdLvl,
+ tcLookupTyCon, tcLookupDataCon, tcLookupId,
+ wellStaged, metaLevel
+ )
+import TcMatches ( tcMatchesCase, tcMatchLambda, tcDoStmts )
+import TcMonoType ( tcHsSigType, UserTypeCtxt(..) )
+import TcPat ( badFieldCon )
+import TcSimplify ( tcSimplifyIPs )
+import TcMType ( tcInstTyVars, tcInstType, newHoleTyVarTy, zapToType,
+ newTyVarTy, newTyVarTys, zonkTcType, readHoleResult )
+import TcType ( TcType, TcSigmaType, TcRhoType, TyVarDetails(VanillaTv),
+ tcSplitFunTys, tcSplitTyConApp, mkTyVarTys,
+ isSigmaTy, isTauTy, mkFunTy, mkFunTys,
+ mkTyConApp, mkClassPred, tcFunArgTy,
+ tyVarsOfTypes, isLinearPred,
+ liftedTypeKind, openTypeKind,
+ tcSplitSigmaTy, tcTyConAppTyCon,
+ tidyOpenType
+ )
+import FieldLabel ( FieldLabel, fieldLabelName, fieldLabelType, fieldLabelTyCon )
+import Id ( Id, idType, recordSelectorFieldLabel, isRecordSelector, isDataConWrapId_maybe )
+import DataCon ( dataConFieldLabels, dataConSig,
+ dataConStrictMarks
+ )
+import Name ( Name, isExternalName )
+import TyCon ( TyCon, tyConTyVars, tyConTheta, isAlgTyCon, tyConDataCons )
+import Subst ( mkTopTyVarSubst, substTheta, substTy )
+import VarSet ( emptyVarSet, elemVarSet )
+import TysWiredIn ( boolTy )
+import PrelNames ( cCallableClassName, cReturnableClassName,
+ enumFromName, enumFromThenName,
+ enumFromToName, enumFromThenToName,
+ enumFromToPName, enumFromThenToPName,
+ ioTyConName, liftName
+ )
+import ListSetOps ( minusList )
+import CmdLineOpts
+import HscTypes ( TyThing(..) )
-tcExpr :: E -> RenamedExpr -> TcM (TypecheckedExpr, LIE, UniType)
+import Util
+import Outputable
+import FastString
\end{code}
%************************************************************************
%* *
-\subsection{The TAUT rules for variables}
+\subsection{Main wrappers}
%* *
%************************************************************************
\begin{code}
-tcExpr e (Var name)
- = specId (lookupE_Value e name) `thenNF_Tc` \ stuff@(expr, lie, ty) ->
+tcExpr :: RenamedHsExpr -- Expession to type check
+ -> TcSigmaType -- Expected type (could be a polytpye)
+ -> TcM TcExpr -- Generalised expr with expected type
+
+tcExpr expr expected_ty
+ = traceTc (text "tcExpr" <+> (ppr expected_ty $$ ppr expr)) `thenM_`
+ tc_expr' expr expected_ty
- -- Check that there's no lurking rank-2 polymorphism
- -- isTauTy is over-paranoid, because we don't expect
- -- any submerged polymorphism other than rank-2 polymorphism
+tc_expr' expr expected_ty
+ | not (isSigmaTy expected_ty) -- Monomorphic case
+ = tcMonoExpr expr expected_ty
- getSrcLocTc `thenNF_Tc` \ loc ->
- checkTc (not (isTauTy ty)) (lurkingRank2Err name ty loc) `thenTc_`
-
- returnTc stuff
+ | otherwise
+ = tcGen expected_ty emptyVarSet (
+ tcMonoExpr expr
+ ) `thenM` \ (gen_fn, expr') ->
+ returnM (gen_fn <$> expr')
\end{code}
+
%************************************************************************
%* *
-\subsection{Literals}
+\subsection{The TAUT rules for variables}
%* *
%************************************************************************
-Overloaded literals.
-
\begin{code}
-tcExpr e (Lit lit@(IntLit i))
- = getSrcLocTc `thenNF_Tc` \ loc ->
- newPolyTyVarTy `thenNF_Tc` \ ty ->
- let
- from_int = lookupE_ClassOpByKey e numClassKey SLIT("fromInt")
- from_integer = lookupE_ClassOpByKey e numClassKey SLIT("fromInteger")
- in
- newOverloadedLit (LiteralOrigin lit loc)
- (OverloadedIntegral i from_int from_integer)
- ty
- `thenNF_Tc` \ over_lit ->
-
- returnTc (Var (mkInstId over_lit), unitLIE over_lit, ty)
-
-tcExpr e (Lit lit@(FracLit f))
- = getSrcLocTc `thenNF_Tc` \ loc ->
- newPolyTyVarTy `thenNF_Tc` \ ty ->
- let
- from_rational = lookupE_ClassOpByKey e fractionalClassKey SLIT("fromRational")
- in
- newOverloadedLit (LiteralOrigin lit loc)
- (OverloadedFractional f from_rational)
- ty
- `thenNF_Tc` \ over_lit ->
-
- returnTc (Var (mkInstId over_lit), unitLIE over_lit, ty)
-
-tcExpr e (Lit lit@(LitLitLitIn s))
- = getSrcLocTc `thenNF_Tc` \ loc ->
- let
- -- Get the callable class. Rather turgid and a HACK (ToDo).
- ce = getE_CE e
- cCallableClass = lookupCE ce (PreludeClass cCallableClassKey bottom)
- bottom = panic "tcExpr:LitLitLit"
- in
- newPolyTyVarTy `thenNF_Tc` \ ty ->
-
- newDict (LitLitOrigin loc (_UNPK_ s)) cCallableClass ty `thenNF_Tc` \ dict ->
-
- returnTc (Lit (LitLitLit s ty), mkLIE [dict], ty)
+tcMonoExpr :: RenamedHsExpr -- Expession to type check
+ -> TcRhoType -- Expected type (could be a type variable)
+ -- Definitely no foralls at the top
+ -- Can be a 'hole'.
+ -> TcM TcExpr
+
+tcMonoExpr (HsVar name) res_ty
+ = tcId name `thenM` \ (expr', id_ty) ->
+ tcSubExp res_ty id_ty `thenM` \ co_fn ->
+ returnM (co_fn <$> expr')
+
+tcMonoExpr (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
+ -- be a tau-type.)
+ newTyVarTy openTypeKind `thenM` \ ip_ty ->
+ newIPDict (IPOcc ip) ip ip_ty `thenM` \ (ip', inst) ->
+ extendLIE inst `thenM_`
+ tcSubExp res_ty ip_ty `thenM` \ co_fn ->
+ returnM (co_fn <$> HsIPVar ip')
\end{code}
-Primitive literals:
-
-\begin{code}
-tcExpr e (Lit (CharPrimLit c))
- = returnTc (Lit (CharPrimLit c), nullLIE, charPrimTy)
-
-tcExpr e (Lit (StringPrimLit s))
- = returnTc (Lit (StringPrimLit s), nullLIE, addrPrimTy)
-
-tcExpr e (Lit (IntPrimLit i))
- = returnTc (Lit (IntPrimLit i), nullLIE, intPrimTy)
-
-tcExpr e (Lit (FloatPrimLit f))
- = returnTc (Lit (FloatPrimLit f), nullLIE, floatPrimTy)
-tcExpr e (Lit (DoublePrimLit d))
- = returnTc (Lit (DoublePrimLit d), nullLIE, doublePrimTy)
-\end{code}
-
-Unoverloaded literals:
+%************************************************************************
+%* *
+\subsection{Expressions type signatures}
+%* *
+%************************************************************************
\begin{code}
-tcExpr e (Lit (CharLit c))
- = returnTc (Lit (CharLit c), nullLIE, charTy)
-
-tcExpr e (Lit (StringLit str))
- = returnTc (Lit (StringLit str), nullLIE, stringTy)
+tcMonoExpr in_expr@(ExprWithTySig expr poly_ty) res_ty
+ = addErrCtxt (exprSigCtxt in_expr) $
+ tcHsSigType ExprSigCtxt poly_ty `thenM` \ sig_tc_ty ->
+ tcExpr expr sig_tc_ty `thenM` \ expr' ->
+
+ -- Must instantiate the outer for-alls of sig_tc_ty
+ -- else we risk instantiating a ? res_ty to a forall-type
+ -- which breaks the invariant that tcMonoExpr only returns phi-types
+ tcInstCall SignatureOrigin sig_tc_ty `thenM` \ (inst_fn, inst_sig_ty) ->
+ tcSubExp res_ty inst_sig_ty `thenM` \ co_fn ->
+
+ returnM (co_fn <$> inst_fn expr')
+
+tcMonoExpr (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)
+ -- so it's not enabled yet.
+ -- Can't eliminate it altogether from the parser, because the
+ -- same parser parses *patterns*.
\end{code}
+
%************************************************************************
%* *
\subsection{Other expression forms}
%************************************************************************
\begin{code}
-tcExpr e (Lam match)
- = tcMatch e match `thenTc` \ (match',lie,ty) ->
- returnTc (Lam match',lie,ty)
+tcMonoExpr (HsLit lit) res_ty = tcLit lit res_ty
+tcMonoExpr (HsOverLit lit) res_ty = newOverloadedLit (LiteralOrigin lit) lit res_ty
+tcMonoExpr (HsPar expr) res_ty = tcMonoExpr expr res_ty `thenM` \ expr' ->
+ returnM (HsPar expr')
+tcMonoExpr (HsSCC lbl expr) res_ty = tcMonoExpr expr res_ty `thenM` \ expr' ->
+ returnM (HsSCC lbl expr')
-tcExpr e (App e1 e2) = accum e1 [e2]
- where
- accum (App e1 e2) args = accum e1 (e2:args)
- accum fun args = tcApp (foldl App) e fun args
--- equivalent to (op e1) e2:
-tcExpr e (OpApp e1 op e2)
- = tcApp (\fun [arg1,arg2] -> OpApp arg1 fun arg2) e op [e1,e2]
+tcMonoExpr (NegApp expr neg_name) res_ty
+ = tcMonoExpr (HsApp (HsVar neg_name) expr) res_ty
+ -- ToDo: use tcSyntaxName
+
+tcMonoExpr (HsLam match) res_ty
+ = tcMatchLambda match res_ty `thenM` \ match' ->
+ returnM (HsLam match')
+
+tcMonoExpr (HsApp e1 e2) res_ty
+ = tcApp e1 [e2] res_ty
\end{code}
Note that the operators in sections are expected to be binary, and
a type error will occur if they aren't.
\begin{code}
--- equivalent to
--- \ x -> e op x,
+-- Left sections, equivalent to
+-- \ x -> e op x,
-- or
--- \ x -> op e x,
+-- \ x -> op e x,
-- or just
-- op e
-tcExpr e (SectionL expr op)
- = tcApp (\ fun [arg] -> SectionL arg fun) e op [expr]
+tcMonoExpr in_expr@(SectionL arg1 op) res_ty
+ = tcExpr_id op `thenM` \ (op', op_ty) ->
+ split_fun_ty op_ty 2 {- two args -} `thenM` \ ([arg1_ty, arg2_ty], op_res_ty) ->
+ tcArg op (arg1, arg1_ty, 1) `thenM` \ arg1' ->
+ addErrCtxt (exprCtxt in_expr) $
+ tcSubExp res_ty (mkFunTy arg2_ty op_res_ty) `thenM` \ co_fn ->
+ returnM (co_fn <$> SectionL arg1' op')
--- equivalent to \ x -> x op expr, or
+-- Right sections, equivalent to \ x -> x op expr, or
-- \ x -> op x expr
-tcExpr e (SectionR op expr)
- = tcExpr e op `thenTc` \ (op', lie1, op_ty) ->
- tcExpr e expr `thenTc` \ (expr',lie2, expr_ty) ->
- newOpenTyVarTy `thenNF_Tc` \ ty1 ->
- newOpenTyVarTy `thenNF_Tc` \ ty2 ->
- let
- result_ty = mkFunTy ty1 ty2
- in
- unifyTauTy op_ty (mkFunTy ty1 (mkFunTy expr_ty ty2))
- (SectionRAppCtxt op expr) `thenTc_`
+tcMonoExpr in_expr@(SectionR op arg2) res_ty
+ = tcExpr_id op `thenM` \ (op', op_ty) ->
+ split_fun_ty op_ty 2 {- two args -} `thenM` \ ([arg1_ty, arg2_ty], op_res_ty) ->
+ tcArg op (arg2, arg2_ty, 2) `thenM` \ arg2' ->
+ addErrCtxt (exprCtxt in_expr) $
+ tcSubExp res_ty (mkFunTy arg1_ty op_res_ty) `thenM` \ co_fn ->
+ returnM (co_fn <$> SectionR op' arg2')
+
+-- equivalent to (op e1) e2:
- returnTc (SectionR op' expr', plusLIE lie1 lie2, result_ty)
+tcMonoExpr in_expr@(OpApp arg1 op fix arg2) res_ty
+ = tcExpr_id op `thenM` \ (op', op_ty) ->
+ split_fun_ty op_ty 2 {- two args -} `thenM` \ ([arg1_ty, arg2_ty], op_res_ty) ->
+ tcArg op (arg1, arg1_ty, 1) `thenM` \ arg1' ->
+ tcArg op (arg2, arg2_ty, 2) `thenM` \ arg2' ->
+ addErrCtxt (exprCtxt in_expr) $
+ tcSubExp res_ty op_res_ty `thenM` \ co_fn ->
+ returnM (OpApp arg1' op' fix arg2')
\end{code}
+\begin{code}
+tcMonoExpr (HsLet binds expr) res_ty
+ = tcBindsAndThen
+ combiner
+ binds -- Bindings to check
+ (tcMonoExpr expr res_ty)
+ where
+ combiner is_rec bind expr = HsLet (mkMonoBind bind [] is_rec) expr
+
+tcMonoExpr in_expr@(HsCase scrut matches src_loc) res_ty
+ = addSrcLoc src_loc $
+ addErrCtxt (caseCtxt in_expr) $
+
+ -- Typecheck the case alternatives first.
+ -- The case patterns tend to give good type info to use
+ -- when typechecking the scrutinee. For example
+ -- case (map f) of
+ -- (x:xs) -> ...
+ -- will report that map is applied to too few arguments
+ --
+ -- Not only that, but it's better to check the matches on their
+ -- own, so that we get the expected results for scoped type variables.
+ -- f x = case x of
+ -- (p::a, q::b) -> (q,p)
+ -- The above should work: the match (p,q) -> (q,p) is polymorphic as
+ -- claimed by the pattern signatures. But if we typechecked the
+ -- match with x in scope and x's type as the expected type, we'd be hosed.
+
+ tcMatchesCase matches res_ty `thenM` \ (scrut_ty, matches') ->
+
+ addErrCtxt (caseScrutCtxt scrut) (
+ tcMonoExpr scrut scrut_ty
+ ) `thenM` \ scrut' ->
+
+ returnM (HsCase scrut' matches' src_loc)
+
+tcMonoExpr (HsIf pred b1 b2 src_loc) res_ty
+ = addSrcLoc src_loc $
+ addErrCtxt (predCtxt pred) (
+ tcMonoExpr pred boolTy ) `thenM` \ pred' ->
+
+ zapToType res_ty `thenM` \ res_ty' ->
+ -- C.f. the call to zapToType in TcMatches.tcMatches
+
+ tcMonoExpr b1 res_ty' `thenM` \ b1' ->
+ tcMonoExpr b2 res_ty' `thenM` \ b2' ->
+ returnM (HsIf pred' b1' b2' src_loc)
+
+tcMonoExpr (HsDo do_or_lc stmts method_names _ src_loc) res_ty
+ = addSrcLoc src_loc $
+ tcDoStmts do_or_lc stmts method_names res_ty `thenM` \ (binds, stmts', methods') ->
+ returnM (mkHsLet binds (HsDo do_or_lc stmts' methods' res_ty src_loc))
+
+tcMonoExpr in_expr@(ExplicitList _ exprs) res_ty -- Non-empty list
+ = unifyListTy res_ty `thenM` \ elt_ty ->
+ mappM (tc_elt elt_ty) exprs `thenM` \ exprs' ->
+ returnM (ExplicitList elt_ty exprs')
+ where
+ tc_elt elt_ty expr
+ = addErrCtxt (listCtxt expr) $
+ tcMonoExpr expr elt_ty
+
+tcMonoExpr in_expr@(ExplicitPArr _ exprs) res_ty -- maybe empty
+ = unifyPArrTy res_ty `thenM` \ elt_ty ->
+ mappM (tc_elt elt_ty) exprs `thenM` \ exprs' ->
+ returnM (ExplicitPArr elt_ty exprs')
+ where
+ tc_elt elt_ty expr
+ = addErrCtxt (parrCtxt expr) $
+ tcMonoExpr expr elt_ty
+
+tcMonoExpr (ExplicitTuple exprs boxity) res_ty
+ = unifyTupleTy boxity (length exprs) res_ty `thenM` \ arg_tys ->
+ tcMonoExprs exprs arg_tys `thenM` \ exprs' ->
+ returnM (ExplicitTuple exprs' boxity)
+\end{code}
+
+
+%************************************************************************
+%* *
+ Foreign calls
+%* *
+%************************************************************************
+
The interesting thing about @ccall@ is that it is just a template
which we instantiate by filling in details about the types of its
argument and result (ie minimal typechecking is performed). So, the
later use.
\begin{code}
-tcExpr e (CCall lbl args may_gc is_asm ignored_fake_result_ty)
- = getSrcLocTc `thenNF_Tc` \ src_loc ->
- let
- -- Get the callable and returnable classes. Rather turgid (ToDo).
- ce = getE_CE e
- cCallableClass = lookupCE ce (PreludeClass cCallableClassKey bottom)
- cReturnableClass = lookupCE ce (PreludeClass cReturnableClassKey bottom)
- bottom = panic "tcExpr:CCall"
+tcMonoExpr e0@(HsCCall lbl args may_gc is_casm ignored_fake_result_ty) res_ty
- new_arg_dict (arg, arg_ty) = newDict (CCallOrigin src_loc (_UNPK_ lbl) (Just arg))
- cCallableClass arg_ty
+ = getDOpts `thenM` \ dflags ->
+
+ checkTc (not (is_casm && dopt_HscLang dflags /= HscC))
+ (vcat [text "_casm_ is only supported when compiling via C (-fvia-C).",
+ text "Either compile with -fvia-C, or, better, rewrite your code",
+ text "to use the foreign function interface. _casm_s are deprecated",
+ text "and support for them may one day disappear."])
+ `thenM_`
+
+ -- Get the callable and returnable classes.
+ tcLookupClass cCallableClassName `thenM` \ cCallableClass ->
+ tcLookupClass cReturnableClassName `thenM` \ cReturnableClass ->
+ tcLookupTyCon ioTyConName `thenM` \ ioTyCon ->
+ let
+ new_arg_dict (arg, arg_ty)
+ = newDicts (CCallOrigin (unpackFS lbl) (Just arg))
+ [mkClassPred cCallableClass [arg_ty]] `thenM` \ arg_dicts ->
+ returnM arg_dicts -- Actually a singleton bag
- result_origin = CCallOrigin src_loc (_UNPK_ lbl) Nothing {- Not an arg -}
+ result_origin = CCallOrigin (unpackFS lbl) Nothing {- Not an arg -}
in
-
+
-- Arguments
- tcExprs e args `thenTc` \ (args', args_lie, arg_tys) ->
+ let tv_idxs | null args = []
+ | otherwise = [1..length args]
+ in
+ newTyVarTys (length tv_idxs) openTypeKind `thenM` \ arg_tys ->
+ tcMonoExprs args arg_tys `thenM` \ args' ->
- -- The argument types can be unboxed or boxed; the result
- -- type must, however, be boxed since it's an argument to the PrimIO
+ -- The argument types can be unlifted or lifted; the result
+ -- type must, however, be lifted since it's an argument to the IO
-- type constructor.
- newPolyTyVarTy `thenNF_Tc` \ result_ty ->
+ newTyVarTy liftedTypeKind `thenM` \ result_ty ->
+ let
+ io_result_ty = mkTyConApp ioTyCon [result_ty]
+ in
+ unifyTauTy res_ty io_result_ty `thenM_`
-- Construct the extra insts, which encode the
-- constraints on the argument and result types.
- mapNF_Tc new_arg_dict (args `zip` arg_tys) `thenNF_Tc` \ arg_dicts ->
- newDict result_origin cReturnableClass result_ty `thenNF_Tc` \ res_dict ->
-
- returnTc (CCall lbl args' may_gc is_asm result_ty,
- args_lie `plusLIE` mkLIE (res_dict : arg_dicts),
- mkPrimIoTy result_ty)
+ mappM new_arg_dict (zipEqual "tcMonoExpr:CCall" args arg_tys) `thenM` \ ccarg_dicts_s ->
+ newDicts result_origin [mkClassPred cReturnableClass [result_ty]] `thenM` \ ccres_dict ->
+ extendLIEs (ccres_dict ++ concat ccarg_dicts_s) `thenM_`
+ returnM (HsCCall lbl args' may_gc is_casm io_result_ty)
\end{code}
-\begin{code}
-tcExpr e (SCC label expr)
- = tcExpr e expr `thenTc` \ (expr', lie, expr_ty) ->
- -- No unification. Give SCC the type of expr
- returnTc (SCC label expr', lie, expr_ty)
-
-tcExpr e (Let binds expr)
- = tcLocalBindsAndThen e
- Let -- The combiner
- binds -- Bindings to check
- (\ e -> tcExpr e expr) -- Typechecker for the expression
-
-tcExpr e (Case expr matches)
- = tcExpr e expr `thenTc` \ (expr',lie1,expr_ty) ->
- tcMatchesCase e matches `thenTc` \ (matches',lie2,match_ty) ->
- newOpenTyVarTy `thenNF_Tc` \ result_ty ->
-
- unifyTauTy (mkFunTy expr_ty result_ty) match_ty
- (CaseCtxt expr matches) `thenTc_`
-
- returnTc (Case expr' matches', plusLIE lie1 lie2, result_ty)
-
-tcExpr e (If pred b1 b2)
- = tcExpr e pred `thenTc` \ (pred',lie1,predTy) ->
-
- unifyTauTy predTy boolTy (PredCtxt pred) `thenTc_`
- tcExpr e b1 `thenTc` \ (b1',lie2,result_ty) ->
- tcExpr e b2 `thenTc` \ (b2',lie3,b2Ty) ->
-
- unifyTauTy result_ty b2Ty (BranchCtxt b1 b2) `thenTc_`
-
- returnTc (If pred' b1' b2', plusLIE lie1 (plusLIE lie2 lie3), result_ty)
+%************************************************************************
+%* *
+ Record construction and update
+%* *
+%************************************************************************
-tcExpr e (ListComp expr quals)
- = mkIdsWithPolyTyVarTys binders `thenNF_Tc` \ lve ->
- -- Binders of a list comprehension must be boxed.
+\begin{code}
+tcMonoExpr expr@(RecordCon con_name rbinds) res_ty
+ = addErrCtxt (recordConCtxt expr) $
+ tcId con_name `thenM` \ (con_expr, con_tau) ->
let
- new_e = growE_LVE e lve
+ (_, record_ty) = tcSplitFunTys con_tau
+ (tycon, ty_args) = tcSplitTyConApp record_ty
in
- tcQuals new_e quals `thenTc` \ (quals',lie1) ->
- tcExpr new_e expr `thenTc` \ (expr', lie2, ty) ->
- returnTc (ListComp expr' quals', plusLIE lie1 lie2, mkListTy ty)
- where
- binders = collectQualBinders quals
-\end{code}
-
-\begin{code}
-tcExpr e (ExplicitList [])
- = newPolyTyVarTy `thenNF_Tc` \ tyvar_ty ->
- returnTc (ExplicitListOut tyvar_ty [], nullLIE, mkListTy tyvar_ty)
-
-
-tcExpr e (ExplicitList exprs) -- Non-empty list
- = tcExprs e exprs `thenTc` \ (exprs', lie, tys@(elt_ty:_)) ->
- unifyTauTyList tys (ListCtxt exprs) `thenTc_`
- returnTc (ExplicitListOut elt_ty exprs', lie, mkListTy elt_ty)
+ ASSERT( isAlgTyCon tycon )
+ unifyTauTy res_ty record_ty `thenM_`
-tcExpr e (ExplicitTuple exprs)
- = tcExprs e exprs `thenTc` \ (exprs', lie, tys) ->
- returnTc (ExplicitTuple exprs', lie, mkTupleTy (length tys) tys)
-
-tcExpr e (ArithSeqIn seq@(From expr))
- = getSrcLocTc `thenNF_Tc` \ loc ->
- tcExpr e expr `thenTc` \ (expr', lie, ty) ->
+ -- Check that the record bindings match the constructor
+ -- con_name is syntactically constrained to be a data constructor
+ tcLookupDataCon con_name `thenM` \ data_con ->
let
- enum_from_id = lookupE_ClassOpByKey e enumClassKey SLIT("enumFrom")
+ bad_fields = badFields rbinds data_con
in
- newMethod (ArithSeqOrigin seq loc)
- enum_from_id [ty] `thenNF_Tc` \ enum_from ->
-
- returnTc (ArithSeqOut (Var (mkInstId enum_from)) (From expr'),
- plusLIE (unitLIE enum_from) lie,
- mkListTy ty)
-
-tcExpr e (ArithSeqIn seq@(FromThen expr1 expr2))
- = getSrcLocTc `thenNF_Tc` \ loc ->
- tcExpr e expr1 `thenTc` \ (expr1',lie1,ty1) ->
- tcExpr e expr2 `thenTc` \ (expr2',lie2,ty2) ->
+ if notNull bad_fields then
+ mappM (addErrTc . badFieldCon data_con) bad_fields `thenM_`
+ failM -- Fail now, because tcRecordBinds will crash on a bad field
+ else
- unifyTauTyList [ty1, ty2] (ArithSeqCtxt (ArithSeqIn seq)) `thenTc_`
+ -- Typecheck the record bindings
+ tcRecordBinds tycon ty_args rbinds `thenM` \ rbinds' ->
+
+ let
+ (missing_s_fields, missing_fields) = missingFields rbinds data_con
+ in
+ checkM (null missing_s_fields)
+ (mappM_ (addErrTc . missingStrictFieldCon con_name) missing_s_fields)
+ `thenM_`
+ doptM Opt_WarnMissingFields `thenM` \ warn ->
+ checkM (not (warn && notNull missing_fields))
+ (mappM_ ((warnTc True) . missingFieldCon con_name) missing_fields)
+ `thenM_`
+
+ returnM (RecordConOut data_con con_expr rbinds')
+
+-- The main complication with RecordUpd is that we need to explicitly
+-- handle the *non-updated* fields. Consider:
+--
+-- data T a b = MkT1 { fa :: a, fb :: b }
+-- | MkT2 { fa :: a, fc :: Int -> Int }
+-- | MkT3 { fd :: a }
+--
+-- upd :: T a b -> c -> T a c
+-- upd t x = t { fb = x}
+--
+-- The type signature on upd is correct (i.e. the result should not be (T a b))
+-- because upd should be equivalent to:
+--
+-- upd t x = case t of
+-- MkT1 p q -> MkT1 p x
+-- MkT2 a b -> MkT2 p b
+-- MkT3 d -> error ...
+--
+-- So we need to give a completely fresh type to the result record,
+-- and then constrain it by the fields that are *not* updated ("p" above).
+--
+-- Note that because MkT3 doesn't contain all the fields being updated,
+-- its RHS is simply an error, so it doesn't impose any type constraints
+--
+-- All this is done in STEP 4 below.
+
+tcMonoExpr expr@(RecordUpd record_expr rbinds) res_ty
+ = addErrCtxt (recordUpdCtxt expr) $
+
+ -- STEP 0
+ -- Check that the field names are really field names
+ ASSERT( notNull rbinds )
+ let
+ field_names = recBindFields rbinds
+ in
+ mappM tcLookupGlobal_maybe field_names `thenM` \ maybe_sel_ids ->
let
- enum_from_then_id = lookupE_ClassOpByKey e enumClassKey SLIT("enumFromThen")
+ bad_guys = [ addErrTc (notSelector field_name)
+ | (field_name, maybe_sel_id) <- field_names `zip` maybe_sel_ids,
+ case maybe_sel_id of
+ Just (AnId sel_id) -> not (isRecordSelector sel_id)
+ other -> True
+ ]
in
- newMethod (ArithSeqOrigin seq loc)
- enum_from_then_id [ty1] `thenNF_Tc` \ enum_from_then ->
+ checkM (null bad_guys) (sequenceM bad_guys `thenM_` failM) `thenM_`
+
+ -- STEP 1
+ -- Figure out the tycon and data cons from the first field name
+ let
+ -- It's OK to use the non-tc splitters here (for a selector)
+ (Just (AnId sel_id) : _) = maybe_sel_ids
+
+ (_, _, tau) = tcSplitSigmaTy (idType sel_id) -- Selectors can be overloaded
+ -- when the data type has a context
+ data_ty = tcFunArgTy tau -- Must succeed since sel_id is a selector
+ tycon = tcTyConAppTyCon data_ty
+ data_cons = tyConDataCons tycon
+ tycon_tyvars = tyConTyVars tycon -- The data cons use the same type vars
+ in
+ tcInstTyVars VanillaTv tycon_tyvars `thenM` \ (_, result_inst_tys, inst_env) ->
+
+ -- STEP 2
+ -- Check that at least one constructor has all the named fields
+ -- i.e. has an empty set of bad fields returned by badFields
+ checkTc (any (null . badFields rbinds) data_cons)
+ (badFieldsUpd rbinds) `thenM_`
+
+ -- STEP 3
+ -- Typecheck the update bindings.
+ -- (Do this after checking for bad fields in case there's a field that
+ -- doesn't match the constructor.)
+ let
+ result_record_ty = mkTyConApp tycon result_inst_tys
+ in
+ unifyTauTy res_ty result_record_ty `thenM_`
+ tcRecordBinds tycon result_inst_tys rbinds `thenM` \ rbinds' ->
+
+ -- STEP 4
+ -- Use the un-updated fields to find a vector of booleans saying
+ -- which type arguments must be the same in updatee and result.
+ --
+ -- WARNING: this code assumes that all data_cons in a common tycon
+ -- have FieldLabels abstracted over the same tyvars.
+ let
+ upd_field_lbls = map recordSelectorFieldLabel (recBindFields rbinds')
+ con_field_lbls_s = map dataConFieldLabels data_cons
+
+ -- A constructor is only relevant to this process if
+ -- it contains all the fields that are being updated
+ relevant_field_lbls_s = filter is_relevant con_field_lbls_s
+ is_relevant con_field_lbls = all (`elem` con_field_lbls) upd_field_lbls
- returnTc (ArithSeqOut (Var (mkInstId enum_from_then))
- (FromThen expr1' expr2'),
- (unitLIE enum_from_then) `plusLIE` lie1 `plusLIE` lie2,
- mkListTy ty1)
+ non_upd_field_lbls = concat relevant_field_lbls_s `minusList` upd_field_lbls
+ common_tyvars = tyVarsOfTypes (map fieldLabelType non_upd_field_lbls)
-tcExpr e (ArithSeqIn seq@(FromTo expr1 expr2))
- = getSrcLocTc `thenNF_Tc` \ loc ->
- tcExpr e expr1 `thenTc` \ (expr1',lie1,ty1) ->
- tcExpr e expr2 `thenTc` \ (expr2',lie2,ty2) ->
+ mk_inst_ty (tyvar, result_inst_ty)
+ | tyvar `elemVarSet` common_tyvars = returnM result_inst_ty -- Same as result type
+ | otherwise = newTyVarTy liftedTypeKind -- Fresh type
+ in
+ mappM mk_inst_ty (zip tycon_tyvars result_inst_tys) `thenM` \ inst_tys ->
- unifyTauTyList [ty1,ty2] (ArithSeqCtxt (ArithSeqIn seq)) `thenTc_`
+ -- STEP 5
+ -- Typecheck the expression to be updated
let
- enum_from_to_id = lookupE_ClassOpByKey e enumClassKey SLIT("enumFromTo")
+ record_ty = mkTyConApp tycon inst_tys
in
- newMethod (ArithSeqOrigin seq loc)
- enum_from_to_id [ty1] `thenNF_Tc` \ enum_from_to ->
- returnTc (ArithSeqOut (Var (mkInstId enum_from_to))
- (FromTo expr1' expr2'),
- (unitLIE enum_from_to) `plusLIE` lie1 `plusLIE` lie2,
- mkListTy ty1)
-
-tcExpr e (ArithSeqIn seq@(FromThenTo expr1 expr2 expr3))
- = getSrcLocTc `thenNF_Tc` \ loc ->
- tcExpr e expr1 `thenTc` \ (expr1',lie1,ty1) ->
- tcExpr e expr2 `thenTc` \ (expr2',lie2,ty2) ->
- tcExpr e expr3 `thenTc` \ (expr3',lie3,ty3) ->
-
- unifyTauTyList [ty1,ty2,ty3] (ArithSeqCtxt (ArithSeqIn seq)) `thenTc_`
+ tcMonoExpr record_expr record_ty `thenM` \ record_expr' ->
+
+ -- STEP 6
+ -- Figure out the LIE we need. We have to generate some
+ -- dictionaries for the data type context, since we are going to
+ -- do pattern matching over the data cons.
+ --
+ -- What dictionaries do we need?
+ -- We just take the context of the type constructor
let
- enum_from_then_to_id = lookupE_ClassOpByKey e enumClassKey SLIT("enumFromThenTo")
+ theta' = substTheta inst_env (tyConTheta tycon)
in
- newMethod (ArithSeqOrigin seq loc)
- enum_from_then_to_id [ty1] `thenNF_Tc` \ enum_from_then_to ->
+ newDicts RecordUpdOrigin theta' `thenM` \ dicts ->
+ extendLIEs dicts `thenM_`
- returnTc (ArithSeqOut (Var (mkInstId enum_from_then_to))
- (FromThenTo expr1' expr2' expr3'),
- (unitLIE enum_from_then_to) `plusLIE` lie1 `plusLIE` lie2 `plusLIE` lie3,
- mkListTy ty1)
+ -- Phew!
+ returnM (RecordUpdOut record_expr' record_ty result_record_ty rbinds')
\end{code}
+
%************************************************************************
%* *
-\subsection{Expressions type signatures}
+ Arithmetic sequences e.g. [a,b..]
+ and their parallel-array counterparts e.g. [: a,b.. :]
+
%* *
%************************************************************************
\begin{code}
-tcExpr e (ExprWithTySig expr poly_ty)
- = tcExpr e expr `thenTc` \ (texpr, lie, tau_ty) ->
- babyTcMtoTcM (tcPolyType (getE_CE e) (getE_TCE e) nullTVE poly_ty) `thenTc` \ sigma_sig ->
-
- -- Check the tau-type part
- specTy SignatureOrigin sigma_sig `thenNF_Tc` \ (sig_tyvars, sig_dicts, sig_tau) ->
- unifyTauTy tau_ty sig_tau (ExprSigCtxt expr sig_tau) `thenTc_`
-
- -- Check the type variables of the signature
- applyTcSubstAndCollectTyVars (tvOfE e) `thenNF_Tc` \ env_tyvars ->
- checkSigTyVars env_tyvars sig_tyvars sig_tau tau_ty (ExprSigCtxt expr sig_tau)
- `thenTc` \ sig_tyvars' ->
-
- -- Check overloading constraints
- tcSimplifyAndCheck
- False {- Not top level -}
- env_tyvars sig_tyvars'
- sig_dicts (unMkLIE lie)
- (ExprSigCtxt expr sigma_sig) `thenTc_`
-
- -- If everything is ok, return the stuff unchanged, except for
- -- the effect of any substutions etc. We simply discard the
- -- result of the tcSimplifyAndCheck, except for any default
- -- resolution it may have done, which is recorded in the
- -- substitution.
- returnTc (texpr, lie, tau_ty)
+tcMonoExpr (ArithSeqIn seq@(From expr)) res_ty
+ = unifyListTy res_ty `thenM` \ elt_ty ->
+ tcMonoExpr expr elt_ty `thenM` \ expr' ->
+
+ newMethodFromName (ArithSeqOrigin seq)
+ elt_ty enumFromName `thenM` \ enum_from ->
+
+ returnM (ArithSeqOut (HsVar enum_from) (From expr'))
+
+tcMonoExpr in_expr@(ArithSeqIn seq@(FromThen expr1 expr2)) res_ty
+ = addErrCtxt (arithSeqCtxt in_expr) $
+ unifyListTy res_ty `thenM` \ elt_ty ->
+ tcMonoExpr expr1 elt_ty `thenM` \ expr1' ->
+ tcMonoExpr expr2 elt_ty `thenM` \ expr2' ->
+ newMethodFromName (ArithSeqOrigin seq)
+ elt_ty enumFromThenName `thenM` \ enum_from_then ->
+
+ returnM (ArithSeqOut (HsVar enum_from_then) (FromThen expr1' expr2'))
+
+
+tcMonoExpr in_expr@(ArithSeqIn seq@(FromTo expr1 expr2)) res_ty
+ = addErrCtxt (arithSeqCtxt in_expr) $
+ unifyListTy res_ty `thenM` \ elt_ty ->
+ tcMonoExpr expr1 elt_ty `thenM` \ expr1' ->
+ tcMonoExpr expr2 elt_ty `thenM` \ expr2' ->
+ newMethodFromName (ArithSeqOrigin seq)
+ elt_ty enumFromToName `thenM` \ enum_from_to ->
+
+ returnM (ArithSeqOut (HsVar enum_from_to) (FromTo expr1' expr2'))
+
+tcMonoExpr in_expr@(ArithSeqIn seq@(FromThenTo expr1 expr2 expr3)) res_ty
+ = addErrCtxt (arithSeqCtxt in_expr) $
+ unifyListTy res_ty `thenM` \ elt_ty ->
+ tcMonoExpr expr1 elt_ty `thenM` \ expr1' ->
+ tcMonoExpr expr2 elt_ty `thenM` \ expr2' ->
+ tcMonoExpr expr3 elt_ty `thenM` \ expr3' ->
+ newMethodFromName (ArithSeqOrigin seq)
+ elt_ty enumFromThenToName `thenM` \ eft ->
+
+ returnM (ArithSeqOut (HsVar eft) (FromThenTo expr1' expr2' expr3'))
+
+tcMonoExpr in_expr@(PArrSeqIn seq@(FromTo expr1 expr2)) res_ty
+ = addErrCtxt (parrSeqCtxt in_expr) $
+ unifyPArrTy res_ty `thenM` \ elt_ty ->
+ tcMonoExpr expr1 elt_ty `thenM` \ expr1' ->
+ tcMonoExpr expr2 elt_ty `thenM` \ expr2' ->
+ newMethodFromName (PArrSeqOrigin seq)
+ elt_ty enumFromToPName `thenM` \ enum_from_to ->
+
+ returnM (PArrSeqOut (HsVar enum_from_to) (FromTo expr1' expr2'))
+
+tcMonoExpr in_expr@(PArrSeqIn seq@(FromThenTo expr1 expr2 expr3)) res_ty
+ = addErrCtxt (parrSeqCtxt in_expr) $
+ unifyPArrTy res_ty `thenM` \ elt_ty ->
+ tcMonoExpr expr1 elt_ty `thenM` \ expr1' ->
+ tcMonoExpr expr2 elt_ty `thenM` \ expr2' ->
+ tcMonoExpr expr3 elt_ty `thenM` \ expr3' ->
+ newMethodFromName (PArrSeqOrigin seq)
+ elt_ty enumFromThenToPName `thenM` \ eft ->
+
+ returnM (PArrSeqOut (HsVar eft) (FromThenTo expr1' expr2' expr3'))
+
+tcMonoExpr (PArrSeqIn _) _
+ = panic "TcExpr.tcMonoExpr: Infinite parallel array!"
+ -- the parser shouldn't have generated it and the renamer shouldn't have
+ -- let it through
\end{code}
+
%************************************************************************
%* *
-\subsection{Data Parallel Expressions (DPH only)}
+ Template Haskell
%* *
%************************************************************************
-Constraints enforced by the Static semantics for ParallelZF
-$exp_1$ = << $exp_2$ | quals >>
+\begin{code}
+#ifdef GHCI /* Only if bootstrapped */
+ -- Rename excludes these cases otherwise
+
+tcMonoExpr (HsSplice n expr) res_ty = tcSpliceExpr n expr res_ty
+
+tcMonoExpr (HsBracket (ExpBr expr)) res_ty
+ = getStage `thenM` \ level ->
+ case bracketOK level of {
+ Nothing -> failWithTc (illegalBracket level) ;
+ Just next_level ->
+
+ -- Typecheck expr to make sure it is valid,
+ -- but throw away the results. We'll type check
+ -- it again when we actually use it.
+ newMutVar [] `thenM` \ pending_splices ->
+ getLIEVar `thenM` \ lie_var ->
+ newTyVarTy openTypeKind `thenM` \ any_ty ->
+
+ setStage (Brack next_level pending_splices lie_var) (
+ getLIE (tcMonoExpr expr any_ty)
+ ) `thenM` \ (expr', lie) ->
+ tcSimplifyBracket lie `thenM_`
+
+ tcMetaTy exprTyConName `thenM` \ meta_exp_ty ->
+ unifyTauTy res_ty meta_exp_ty `thenM_`
+
+ -- Return the original expression, not the type-decorated one
+ readMutVar pending_splices `thenM` \ pendings ->
+ returnM (HsBracketOut (ExpBr expr) pendings)
+ }
+#endif GHCI
+\end{code}
-\begin{enumerate}
-\item The type of the expression $exp_1$ is <<$exp_2$>>
-\item The type of $exp_2$ must be in the class {\tt Processor}
-\end{enumerate}
+%************************************************************************
+%* *
+\subsection{Implicit Parameter bindings}
+%* *
+%************************************************************************
\begin{code}
-#ifdef DPH
-tcExpr e (ParallelZF expr quals)
- = let binders = collectParQualBinders quals in
- mkIdsWithPolyTyVarTys binders `thenNF_Tc` (\ lve ->
- let e' = growE_LVE e lve in
- tcParQuals e' quals `thenTc` (\ (quals',lie1) ->
- tcExpr e' expr `thenTc` (\ (expr', lie2,ty) ->
- getSrcLocTc `thenNF_Tc` (\ src_loc ->
- if (isProcessorTy ty) then
- returnTc (ParallelZF expr' quals',
- plusLIE lie1 lie2 ,
- mkPodTy ty)
- else
- failTc (podCompLhsError ty src_loc)
- ))))
-#endif {- Data Parallel Haskell -}
+tcMonoExpr (HsWith expr binds is_with) res_ty
+ = getLIE (tcMonoExpr expr res_ty) `thenM` \ (expr', expr_lie) ->
+ mapAndUnzipM tc_ip_bind binds `thenM` \ (avail_ips, binds') ->
+
+ -- If the binding binds ?x = E, we must now
+ -- discharge any ?x constraints in expr_lie
+ tcSimplifyIPs avail_ips expr_lie `thenM` \ dict_binds ->
+ let
+ expr'' = HsLet (mkMonoBind dict_binds [] Recursive) expr'
+ in
+ returnM (HsWith expr'' binds' is_with)
+ where
+ tc_ip_bind (ip, expr)
+ = newTyVarTy openTypeKind `thenM` \ ty ->
+ getSrcLocM `thenM` \ loc ->
+ newIPDict (IPBind ip) ip ty `thenM` \ (ip', ip_inst) ->
+ tcMonoExpr expr ty `thenM` \ expr' ->
+ returnM (ip_inst, (ip', expr'))
\end{code}
-Constraints enforced by the Static semantics for Explicit Pods
-exp = << $exp_1$ ... $exp_n$>> (where $n >= 0$)
-\begin{enumerate}
-\item The type of the all the expressions in the Pod must be the same.
-\item The type of an expression in a POD must be in class {\tt Processor}
-\end{enumerate}
+%************************************************************************
+%* *
+ Catch-all
+%* *
+%************************************************************************
\begin{code}
-#ifdef DPH
-tcExpr e (ExplicitPodIn exprs)
- = panic "Ignoring explicit PODs for the time being"
-{-
- = tcExprs e exprs `thenTc` (\ (exprs',lie,tys) ->
- newPolyTyVarTy `thenNF_Tc` (\ elt_ty ->
- newDict processorClass elt_ty `thenNF_Tc` (\ procDict ->
- let
- procLie = mkLIEFromDicts procDict
- in
- unifyTauTyList (elt_ty:tys) (PodCtxt exprs) `thenTc_`
-
- returnTc ((App
- (DictApp
- (TyApp (Var toPodId) [elt_ty])
- procDict)
- (ExplicitListOut elt_ty exprs')),
- plusLIE procLie lie,
- mkPodTy elt_ty)
- ))) -}
-#endif {- Data Parallel Haskell -}
+tcMonoExpr other _ = pprPanic "tcMonoExpr" (ppr other)
\end{code}
-\begin{code}
-#ifdef DPH
-tcExpr e (ExplicitProcessor exprs expr)
- = tcPidExprs e exprs `thenTc` (\ (exprs',lie1,tys) ->
- tcExpr e expr `thenTc` (\ (expr',lie2,ty) ->
- returnTc (ExplicitProcessor exprs' expr',
- plusLIE lie1 lie2,
- mkProcessorTy tys ty)
- ))
-#endif {- Data Parallel Haskell -}
-\end{code}
%************************************************************************
%* *
-\subsection{@tcExprs@ typechecks a {\em list} of expressions}
+\subsection{@tcApp@ typchecks an application}
%* *
%************************************************************************
-ToDo: Possibly find a version of a listTc TcM which would pass the
-appropriate functions for the LIE.
+\begin{code}
+
+tcApp :: RenamedHsExpr -> [RenamedHsExpr] -- Function and args
+ -> TcType -- Expected result type of application
+ -> TcM TcExpr -- Translated fun and args
+
+tcApp (HsApp e1 e2) args res_ty
+ = tcApp e1 (e2:args) res_ty -- Accumulate the arguments
+
+tcApp fun args res_ty
+ = -- First type-check the function
+ tcExpr_id fun `thenM` \ (fun', fun_ty) ->
+
+ addErrCtxt (wrongArgsCtxt "too many" fun args) (
+ traceTc (text "tcApp" <+> (ppr fun $$ ppr fun_ty)) `thenM_`
+ split_fun_ty fun_ty (length args)
+ ) `thenM` \ (expected_arg_tys, actual_result_ty) ->
+
+ -- Now typecheck the args
+ mappM (tcArg fun)
+ (zip3 args expected_arg_tys [1..]) `thenM` \ args' ->
+
+ -- Unify with expected result after type-checking the args
+ -- so that the info from args percolates to actual_result_ty.
+ -- This is when we might detect a too-few args situation.
+ -- (One can think of cases when the opposite order would give
+ -- a better error message.)
+ addErrCtxtM (checkArgsCtxt fun args res_ty actual_result_ty)
+ (tcSubExp res_ty actual_result_ty) `thenM` \ co_fn ->
+
+ returnM (co_fn <$> foldl HsApp fun' args')
+
+
+-- If an error happens we try to figure out whether the
+-- function has been given too many or too few arguments,
+-- and say so
+checkArgsCtxt fun args expected_res_ty actual_res_ty tidy_env
+ = zonkTcType expected_res_ty `thenM` \ exp_ty' ->
+ zonkTcType actual_res_ty `thenM` \ act_ty' ->
+ let
+ (env1, exp_ty'') = tidyOpenType tidy_env exp_ty'
+ (env2, act_ty'') = tidyOpenType env1 act_ty'
+ (exp_args, _) = tcSplitFunTys exp_ty''
+ (act_args, _) = tcSplitFunTys act_ty''
+
+ len_act_args = length act_args
+ len_exp_args = length exp_args
+
+ message | len_exp_args < len_act_args = wrongArgsCtxt "too few" fun args
+ | len_exp_args > len_act_args = wrongArgsCtxt "too many" fun args
+ | otherwise = appCtxt fun args
+ in
+ returnM (env2, message)
+
+
+split_fun_ty :: TcType -- The type of the function
+ -> Int -- Number of arguments
+ -> TcM ([TcType], -- Function argument types
+ TcType) -- Function result types
+
+split_fun_ty fun_ty 0
+ = returnM ([], fun_ty)
+
+split_fun_ty fun_ty n
+ = -- Expect the function to have type A->B
+ unifyFunTy fun_ty `thenM` \ (arg_ty, res_ty) ->
+ split_fun_ty res_ty (n-1) `thenM` \ (arg_tys, final_res_ty) ->
+ returnM (arg_ty:arg_tys, final_res_ty)
+\end{code}
\begin{code}
-tcExprs :: E -> [RenamedExpr] -> TcM ([TypecheckedExpr],LIE,[TauType])
+tcArg :: RenamedHsExpr -- The function (for error messages)
+ -> (RenamedHsExpr, TcSigmaType, Int) -- Actual argument and expected arg type
+ -> TcM TcExpr -- Resulting argument and LIE
-tcExprs e [] = returnTc ([], nullLIE, [])
-tcExprs e (expr:exprs)
- = tcExpr e expr `thenTc` \ (expr', lie1, ty) ->
- tcExprs e exprs `thenTc` \ (exprs', lie2, tys) ->
- returnTc (expr':exprs', plusLIE lie1 lie2, ty:tys)
+tcArg the_fun (arg, expected_arg_ty, arg_no)
+ = addErrCtxt (funAppCtxt the_fun arg arg_no) $
+ tcExpr arg expected_arg_ty
\end{code}
%************************************************************************
%* *
-\subsection{@tcApp@ typchecks an application}
+\subsection{@tcId@ typchecks an identifier occurrence}
%* *
%************************************************************************
+tcId instantiates an occurrence of an Id.
+The instantiate_it loop runs round instantiating the Id.
+It has to be a loop because we are now prepared to entertain
+types like
+ f:: forall a. Eq a => forall b. Baz b => tau
+We want to instantiate this to
+ f2::tau {f2 = f1 b (Baz b), f1 = f a (Eq a)}
+
+The -fno-method-sharing flag controls what happens so far as the LIE
+is concerned. The default case is that for an overloaded function we
+generate a "method" Id, and add the Method Inst to the LIE. So you get
+something like
+ f :: Num a => a -> a
+ f = /\a (d:Num a) -> let m = (+) a d in \ (x:a) -> m x x
+If you specify -fno-method-sharing, the dictionary application
+isn't shared, so we get
+ f :: Num a => a -> a
+ f = /\a (d:Num a) (x:a) -> (+) a d x x
+This gets a bit less sharing, but
+ a) it's better for RULEs involving overloaded functions
+ b) perhaps fewer separated lambdas
+
\begin{code}
-tcApp :: (TypecheckedExpr -> [TypecheckedExpr] -> TypecheckedExpr) -- Result builder
- -> E
- -> RenamedExpr
- -> [RenamedExpr]
- -> TcM (TypecheckedExpr, LIE, UniType)
-
-tcApp build_result_expression e orig_fun arg_exprs
- = tcExpr' e orig_fun (length arg_exprs)
- `thenTc` \ (fun', lie_fun, fun_ty) ->
- unify_fun 1 fun' lie_fun arg_exprs fun_ty
- where
- -- Used only in the error message
- maybe_fun_id = case orig_fun of
- Var name -> Just (lookupE_Value e name)
- other -> Nothing
-
- unify_args :: Int -- Current argument number
- -> TypecheckedExpr -- Current rebuilt expression
- -> LIE -- Corresponding LIE
- -> [RenamedExpr] -- Remaining args
- -> [TauType] -- Remaining arg types
- -> TauType -- result type
- -> TcM (TypecheckedExpr, LIE, UniType)
-
- unify_args arg_no fun lie (arg:args) (arg_ty:arg_tys) fun_res_ty
- = tcExpr e arg `thenTc` \ (arg', lie_arg, actual_arg_ty) ->
-
- -- These applyTcSubstToTy's are just to improve the error message...
- applyTcSubstToTy actual_arg_ty `thenNF_Tc` \ actual_arg_ty' ->
- applyTcSubstToTy arg_ty `thenNF_Tc` \ arg_ty' ->
+tcId :: Name -> TcM (TcExpr, TcType)
+tcId name -- Look up the Id and instantiate its type
+ = tcLookupIdLvl name `thenM` \ (id, bind_lvl) ->
+
+ -- Check for cross-stage lifting
+ getStage `thenM` \ use_stage ->
+ case use_stage of
+ Brack use_lvl ps_var lie_var
+ | use_lvl > bind_lvl && not (isExternalName name)
+ -> -- 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
+ -- NB: isExernalName is true of top level things,
+ -- and false of nested bindings
+
let
- err_ctxt = FunAppCtxt orig_fun maybe_fun_id arg arg_ty' actual_arg_ty' arg_no
+ id_ty = idType id
in
- matchArgTy e arg_ty' arg' lie_arg actual_arg_ty' err_ctxt
- `thenTc` \ (arg'', lie_arg') ->
+ 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 liftName `thenM` \ lift ->
+ -- Put the 'lift' constraint into the right LIE
+
+ -- Update the pending splices
+ readMutVar ps_var `thenM` \ ps ->
+ writeMutVar ps_var ((name, HsApp (HsVar lift) (HsVar id)) : ps) `thenM_`
- unify_args (arg_no+1) (App fun arg'') (lie `plusLIE` lie_arg') args arg_tys fun_res_ty
+ returnM (HsVar id, id_ty))
- unify_args arg_no fun lie [] arg_tys fun_res_ty
- = -- We've run out of actual arguments. Check that none of
- -- arg_tys has a for-all at the top. For example, "build" on
- -- its own is no good; it must be applied to something.
+ other ->
let
- result_ty = glueTyArgs arg_tys fun_res_ty
+ use_lvl = metaLevel use_stage
in
- getSrcLocTc `thenNF_Tc` \ loc ->
- checkTc (not (isTauTy result_ty))
- (underAppliedTyErr result_ty loc) `thenTc_`
- returnTc (fun, lie, result_ty)
+ checkTc (wellStaged bind_lvl use_lvl)
+ (badStageErr id bind_lvl use_lvl) `thenM_`
- -- When we run out of arg_tys we go back to unify_fun in the hope
- -- that our unification work may have shown up some more arguments
- unify_args arg_no fun lie args [] fun_res_ty
- = unify_fun arg_no fun lie args fun_res_ty
+ case isDataConWrapId_maybe id of
+ Nothing -> loop (HsVar id) (idType id)
+ Just data_con -> inst_data_con id data_con
+ where
+ orig = OccurrenceOf name
+
+ loop (HsVar fun_id) fun_ty
+ | want_method_inst fun_ty
+ = tcInstType VanillaTv fun_ty `thenM` \ (tyvars, theta, tau) ->
+ newMethodWithGivenTy orig fun_id
+ (mkTyVarTys tyvars) theta tau `thenM` \ meth ->
+ loop (HsVar (instToId meth)) tau
+
+ loop fun fun_ty
+ | isSigmaTy fun_ty
+ = tcInstCall orig fun_ty `thenM` \ (inst_fn, tau) ->
+ loop (inst_fn fun) tau
+
+ | otherwise
+ = returnM (fun, fun_ty)
+
+ want_method_inst fun_ty
+ | opt_NoMethodSharing = False
+ | otherwise = case tcSplitSigmaTy fun_ty of
+ (_,[],_) -> False -- Not overloaded
+ (_,theta,_) -> not (any isLinearPred theta)
+ -- This is a slight hack.
+ -- If f :: (%x :: T) => Int -> Int
+ -- Then if we have two separate calls, (f 3, f 4), we cannot
+ -- make a method constraint that then gets shared, thus:
+ -- let m = f %x in (m 3, m 4)
+ -- because that loses the linearity of the constraint.
+ -- The simplest thing to do is never to construct a method constraint
+ -- in the first place that has a linear implicit parameter in it.
+
+ -- We treat data constructors differently, because we have to generate
+ -- constraints for their silly theta, which no longer appears in
+ -- the type of dataConWrapId. It's dual to TcPat.tcConstructor
+ inst_data_con id data_con
+ = tcInstDataCon orig data_con `thenM` \ (ty_args, ex_dicts, arg_tys, result_ty, _) ->
+ extendLIEs ex_dicts `thenM_`
+ returnM (mkHsDictApp (mkHsTyApp (HsVar id) ty_args) (map instToId ex_dicts),
+ mkFunTys arg_tys result_ty)
+\end{code}
- unify_fun :: Int -- Current argument number
- -> TypecheckedExpr -- Current rebuilt expression
- -> LIE -- Corresponding LIE
- -> [RenamedExpr] -- Remaining args
- -> TauType -- Remaining function type
- -> TcM (TypecheckedExpr, LIE, UniType)
+Typecheck expression which in most cases will be an Id.
+The expression can return a higher-ranked type, such as
+ (forall a. a->a) -> Int
+so we must create a HoleTyVarTy to pass in as the expected tyvar.
- unify_fun arg_no fun lie args fun_ty
- = -- Find out as much as possible about the function
- applyTcSubstToTy fun_ty `thenNF_Tc` \ fun_ty' ->
+\begin{code}
+tcExpr_id :: RenamedHsExpr -> TcM (TcExpr, TcType)
+tcExpr_id (HsVar name) = tcId name
+tcExpr_id expr = newHoleTyVarTy `thenM` \ id_ty ->
+ tcMonoExpr expr id_ty `thenM` \ expr' ->
+ readHoleResult id_ty `thenM` \ id_ty' ->
+ returnM (expr', id_ty')
+\end{code}
- -- Now see whether it has any arguments
- case (splitTyArgs fun_ty') of
- ([], _) -> -- Function has no arguments left
+%************************************************************************
+%* *
+\subsection{Record bindings}
+%* *
+%************************************************************************
- newOpenTyVarTy `thenNF_Tc` \ result_ty ->
- tcExprs e args `thenTc` \ (args', lie_args, arg_tys) ->
+Game plan for record bindings
+~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+1. Find the TyCon for the bindings, from the first field label.
- -- At this point, a unification error must mean the function is
- -- being applied to too many arguments.
- unifyTauTy fun_ty' (glueTyArgs arg_tys result_ty)
- (TooManyArgsCtxt orig_fun) `thenTc_`
+2. Instantiate its tyvars and unify (T a1 .. an) with expected_ty.
- returnTc (build_result_expression fun args',
- lie `plusLIE` lie_args,
- result_ty)
+For each binding field = value
- (fun_arg_tys, fun_res_ty) -> -- Function has non-empty list of argument types
+3. Instantiate the field type (from the field label) using the type
+ envt from step 2.
- unify_args arg_no fun lie args fun_arg_tys fun_res_ty
-\end{code}
+4 Type check the value using tcArg, passing the field type as
+ the expected argument type.
+This extends OK when the field types are universally quantified.
+
+
\begin{code}
-matchArgTy :: E
- -> UniType -- Expected argument type
- -> TypecheckedExpr -- Type checked argument
- -> LIE -- Actual argument LIE
- -> UniType -- Actual argument type
- -> UnifyErrContext
- -> TcM (TypecheckedExpr, -- The incoming type checked arg,
- -- possibly wrapped in a big lambda
- LIE) -- Possibly reduced somewhat
-
-matchArgTy e expected_arg_ty arg_expr actual_arg_lie actual_arg_ty err_ctxt
- | isForAllTy expected_arg_ty
- = -- Ha! The argument type of the function is a for-all type,
- -- An example of rank-2 polymorphism.
-
- -- This applyTcSubstToTy is just to improve the error message..
-
- applyTcSubstToTy actual_arg_ty `thenNF_Tc` \ actual_arg_ty' ->
-
- -- Instantiate the argument type
- -- ToDo: give this a real origin
- specTy UnknownOrigin expected_arg_ty `thenNF_Tc` \ (arg_tyvars, arg_lie, arg_tau) ->
-
- if not (null arg_lie) then
- -- Paranoia check
- panic "Non-null overloading in tcApp"
- else
- -- Assert: arg_lie = []
-
- unifyTauTy arg_tau actual_arg_ty' err_ctxt `thenTc_`
-
- -- Check that the arg_tyvars havn't been constrained
- -- The interesting bit here is that we must include the free variables
- -- of the expected arg ty. Here's an example:
- -- runST (newVar True)
- -- Here, if we don't make a check, we'll get a type (ST s (MutVar s Bool))
- -- for (newVar True), with s fresh. Then we unify with the runST's arg type
- -- forall s'. ST s' a. That unifies s' with s, and a with MutVar s Bool.
- -- So now s' isn't unconstrained because it's linked to a.
- -- Conclusion: include the free vars of the expected arg type in the
- -- list of "free vars" for the signature check.
- applyTcSubstAndCollectTyVars
- (tvOfE e `unionLists`
- extractTyVarsFromTy expected_arg_ty) `thenNF_Tc` \ free_tyvars ->
- checkSigTyVars free_tyvars arg_tyvars arg_tau actual_arg_ty rank2_err_ctxt
- `thenTc` \ arg_tyvars' ->
-
- -- Check that there's no overloading involved
- -- Even if there isn't, there may be some Insts which mention the arg_tyvars,
- -- but which, on simplification, don't actually need a dictionary involving
- -- the tyvar. So we have to do a proper simplification right here.
- let insts = unMkLIE actual_arg_lie
- in
- applyTcSubstToInsts insts `thenNF_Tc` \ insts' ->
+tcRecordBinds
+ :: TyCon -- Type constructor for the record
+ -> [TcType] -- Args of this type constructor
+ -> RenamedRecordBinds
+ -> TcM TcRecordBinds
+
+tcRecordBinds tycon ty_args rbinds
+ = mappM do_bind rbinds
+ where
+ tenv = mkTopTyVarSubst (tyConTyVars tycon) ty_args
- tcSimplifyRank2 arg_tyvars' insts' rank2_err_ctxt `thenTc` \ (free_insts, inst_binds) ->
+ do_bind (field_lbl_name, rhs)
+ = addErrCtxt (fieldCtxt field_lbl_name) $
+ tcLookupId field_lbl_name `thenM` \ sel_id ->
+ let
+ field_lbl = recordSelectorFieldLabel sel_id
+ field_ty = substTy tenv (fieldLabelType field_lbl)
+ in
+ ASSERT( isRecordSelector sel_id )
+ -- This lookup and assertion will surely succeed, because
+ -- we check that the fields are indeed record selectors
+ -- before calling tcRecordBinds
+ ASSERT2( fieldLabelTyCon field_lbl == tycon, ppr field_lbl )
+ -- The caller of tcRecordBinds has already checked
+ -- that all the fields come from the same type
- -- This Let binds any Insts which came out of the simplification.
- -- It's a bit out of place here, but using AbsBind involves inventing
- -- a couple of new names which seems worse.
- returnTc (TyLam arg_tyvars' (Let (mk_binds inst_binds) arg_expr), mkLIE free_insts)
+ tcExpr rhs field_ty `thenM` \ rhs' ->
- | otherwise
- = -- The ordinary, non-rank-2 polymorphic case
- unifyTauTy expected_arg_ty actual_arg_ty err_ctxt `thenTc_`
- returnTc (arg_expr, actual_arg_lie)
+ returnM (sel_id, rhs')
+badFields rbinds data_con
+ = filter (not . (`elem` field_names)) (recBindFields rbinds)
where
- rank2_err_ctxt = Rank2ArgCtxt arg_expr expected_arg_ty
+ field_names = map fieldLabelName (dataConFieldLabels data_con)
+
+missingFields rbinds data_con
+ | null field_labels = ([], []) -- Not declared as a record;
+ -- But C{} is still valid
+ | otherwise
+ = (missing_strict_fields, other_missing_fields)
+ where
+ missing_strict_fields
+ = [ fl | (fl, str) <- field_info,
+ isMarkedStrict str,
+ not (fieldLabelName fl `elem` field_names_used)
+ ]
+ other_missing_fields
+ = [ fl | (fl, str) <- field_info,
+ not (isMarkedStrict str),
+ not (fieldLabelName fl `elem` field_names_used)
+ ]
+
+ field_names_used = recBindFields rbinds
+ field_labels = dataConFieldLabels data_con
+
+ field_info = zipEqual "missingFields"
+ field_labels
+ (dropList ex_theta (dataConStrictMarks data_con))
+ -- The 'drop' is because dataConStrictMarks
+ -- includes the existential dictionaries
+ (_, _, _, ex_theta, _, _) = dataConSig data_con
+\end{code}
+
+%************************************************************************
+%* *
+\subsection{@tcMonoExprs@ typechecks a {\em list} of expressions}
+%* *
+%************************************************************************
+
+\begin{code}
+tcMonoExprs :: [RenamedHsExpr] -> [TcType] -> TcM [TcExpr]
+
+tcMonoExprs [] [] = returnM []
+tcMonoExprs (expr:exprs) (ty:tys)
+ = tcMonoExpr expr ty `thenM` \ expr' ->
+ tcMonoExprs exprs tys `thenM` \ exprs' ->
+ returnM (expr':exprs')
+\end{code}
+
+
+%************************************************************************
+%* *
+\subsection{Literals}
+%* *
+%************************************************************************
- mk_binds [] = EmptyBinds
- mk_binds ((inst,rhs):inst_binds) = (SingleBind (NonRecBind (VarMonoBind (mkInstId inst) rhs)))
- `ThenBinds`
- mk_binds inst_binds
+Overloaded literals.
+
+\begin{code}
+tcLit :: HsLit -> TcType -> TcM TcExpr
+tcLit (HsLitLit s _) res_ty
+ = tcLookupClass cCallableClassName `thenM` \ cCallableClass ->
+ newDicts (LitLitOrigin (unpackFS s))
+ [mkClassPred cCallableClass [res_ty]] `thenM` \ dicts ->
+ extendLIEs dicts `thenM_`
+ returnM (HsLit (HsLitLit s res_ty))
+
+tcLit lit res_ty
+ = unifyTauTy res_ty (hsLitType lit) `thenM_`
+ returnM (HsLit lit)
\end{code}
-This version only does not check for 2nd order if it is applied.
+%************************************************************************
+%* *
+\subsection{Errors and contexts}
+%* *
+%************************************************************************
+
+Boring and alphabetical:
\begin{code}
-tcExpr' :: E -> RenamedExpr -> Int -> TcM (TypecheckedExpr,LIE,UniType)
+arithSeqCtxt expr
+ = hang (ptext SLIT("In an arithmetic sequence:")) 4 (ppr expr)
+
+
+badStageErr id bind_lvl use_lvl
+ = ptext SLIT("Stage error:") <+> quotes (ppr id) <+>
+ hsep [ptext SLIT("is bound at stage") <+> ppr bind_lvl,
+ ptext SLIT("but used at stage") <+> ppr use_lvl]
-tcExpr' e v@(Var name) n
- | n > 0 = specId (lookupE_Value e name) `thenNF_Tc` \ (expr, lie, ty) ->
- returnTc (expr, lie, ty)
-tcExpr' e exp n = tcExpr e exp
+parrSeqCtxt expr
+ = hang (ptext SLIT("In a parallel array sequence:")) 4 (ppr expr)
+
+caseCtxt expr
+ = hang (ptext SLIT("In the case expression:")) 4 (ppr expr)
+
+caseScrutCtxt expr
+ = hang (ptext SLIT("In the scrutinee of a case expression:")) 4 (ppr expr)
+
+exprSigCtxt expr
+ = hang (ptext SLIT("When checking the type signature of the expression:"))
+ 4 (ppr expr)
+
+exprCtxt expr
+ = hang (ptext SLIT("In the expression:")) 4 (ppr expr)
+
+fieldCtxt field_name
+ = ptext SLIT("In the") <+> quotes (ppr field_name) <+> ptext SLIT("field of a record")
+
+funAppCtxt fun arg arg_no
+ = hang (hsep [ ptext SLIT("In the"), speakNth arg_no, ptext SLIT("argument of"),
+ quotes (ppr fun) <> text ", namely"])
+ 4 (quotes (ppr arg))
+
+listCtxt expr
+ = hang (ptext SLIT("In the list element:")) 4 (ppr expr)
+
+parrCtxt expr
+ = hang (ptext SLIT("In the parallel array element:")) 4 (ppr expr)
+
+predCtxt expr
+ = hang (ptext SLIT("In the predicate expression:")) 4 (ppr expr)
+
+illegalBracket level
+ = ptext SLIT("Illegal bracket at level") <+> ppr level
+
+appCtxt fun args
+ = ptext SLIT("In the application") <+> quotes (ppr the_app)
+ where
+ the_app = foldl HsApp fun args -- Used in error messages
+
+lurkingRank2Err fun fun_ty
+ = hang (hsep [ptext SLIT("Illegal use of"), quotes (ppr fun)])
+ 4 (vcat [ptext SLIT("It is applied to too few arguments"),
+ ptext SLIT("so that the result type has for-alls in it:") <+> ppr fun_ty])
+
+badFieldsUpd rbinds
+ = hang (ptext SLIT("No constructor has all these fields:"))
+ 4 (pprQuotedList (recBindFields rbinds))
+
+recordUpdCtxt expr = ptext SLIT("In the record update:") <+> ppr expr
+recordConCtxt expr = ptext SLIT("In the record construction:") <+> ppr expr
+
+notSelector field
+ = hsep [quotes (ppr field), ptext SLIT("is not a record selector")]
+
+missingStrictFieldCon :: Name -> FieldLabel -> SDoc
+missingStrictFieldCon con field
+ = hsep [ptext SLIT("Constructor") <+> quotes (ppr con),
+ ptext SLIT("does not have the required strict field"), quotes (ppr field)]
+
+missingFieldCon :: Name -> FieldLabel -> SDoc
+missingFieldCon con field
+ = hsep [ptext SLIT("Field") <+> quotes (ppr field),
+ ptext SLIT("is not initialised")]
+
+polySpliceErr :: Id -> SDoc
+polySpliceErr id
+ = ptext SLIT("Can't splice the polymorphic local variable") <+> quotes (ppr id)
+
+wrongArgsCtxt too_many_or_few fun args
+ = hang (ptext SLIT("Probable cause:") <+> quotes (ppr fun)
+ <+> ptext SLIT("is applied to") <+> text too_many_or_few
+ <+> ptext SLIT("arguments in the call"))
+ 4 (parens (ppr the_app))
+ where
+ the_app = foldl HsApp fun args -- Used in error messages
\end{code}
projects / ghc-hetmet.git / blobdiff