%
+% (c) The University of Glasgow 2006
% (c) The GRASP/AQUA Project, Glasgow University, 1992-1998
%
-\section[TcMatches]{Typecheck some @Matches@}
+
+TcMatches: Typecheck some @Matches@
\begin{code}
module TcMatches ( tcMatchesFun, tcGRHSsPat, tcMatchesCase, tcMatchLambda,
import {-# SOURCE #-} TcExpr( tcSyntaxOp, tcInferRho, tcMonoExpr, tcPolyExpr )
-import HsSyn ( HsExpr(..), LHsExpr, MatchGroup(..),
- Match(..), LMatch, GRHSs(..), GRHS(..),
- Stmt(..), LStmt, HsMatchContext(..),
- HsStmtContext(..),
- pprMatch, isIrrefutableHsPat, mkHsCoerce,
- mkLHsCoerce, pprMatchContext, pprStmtContext,
- noSyntaxExpr, matchGroupArity, pprMatches,
- ExprCoFn )
-
+import HsSyn
import TcRnMonad
-import TcGadt ( Refinement, emptyRefinement, refineResType )
-import Inst ( newMethodFromName )
-import TcEnv ( TcId, tcLookupLocalIds, tcLookupId, tcExtendIdEnv )
-import TcPat ( tcLamPats, tcLamPat )
-import TcMType ( newFlexiTyVarTy, newFlexiTyVarTys )
-import TcType ( TcType, TcRhoType,
- BoxySigmaType, BoxyRhoType,
- mkFunTys, mkFunTy, mkAppTy, mkTyConApp,
- liftedTypeKind )
-import TcBinds ( tcLocalBinds )
-import TcUnify ( boxySplitAppTy, boxySplitTyConApp, boxySplitListTy,
- subFunTys, tcSubExp, withBox )
-import TcSimplify ( bindInstsOfLocalFuns )
-import Name ( Name )
-import TysWiredIn ( stringTy, boolTy, parrTyCon, listTyCon, mkListTy, mkPArrTy )
-import PrelNames ( bindMName, returnMName, mfixName, thenMName, failMName )
-import Id ( idType, mkLocalId )
-import TyCon ( TyCon )
+import TcGadt
+import Inst
+import TcEnv
+import TcPat
+import TcMType
+import TcType
+import TcBinds
+import TcUnify
+import TcSimplify
+import Name
+import TysWiredIn
+import PrelNames
+import Id
+import TyCon
import Outputable
-import SrcLoc ( Located(..), getLoc )
+import SrcLoc
\end{code}
%************************************************************************
same number of arguments before using @tcMatches@ to do the work.
\begin{code}
-tcMatchesFun :: Name
+tcMatchesFun :: Name -> Bool
-> MatchGroup Name
-> BoxyRhoType -- Expected type of function
- -> TcM (ExprCoFn, MatchGroup TcId) -- Returns type of body
+ -> TcM (HsWrapper, MatchGroup TcId) -- Returns type of body
-tcMatchesFun fun_name matches exp_ty
+tcMatchesFun fun_name inf matches exp_ty
= do { -- Check that they all have the same no of arguments
-- Location is in the monad, set the caller so that
-- any inter-equation error messages get some vaguely
doc = ptext SLIT("The equation(s) for") <+> quotes (ppr fun_name)
<+> ptext SLIT("have") <+> speakNOf n_pats (ptext SLIT("argument"))
n_pats = matchGroupArity matches
- match_ctxt = MC { mc_what = FunRhs fun_name, mc_body = tcBody }
+ match_ctxt = MC { mc_what = FunRhs fun_name inf, mc_body = tcBody }
\end{code}
@tcMatchesCase@ doesn't do the argument-count check because the
tcMatchesCase ctxt scrut_ty matches res_ty
= tcMatches ctxt [scrut_ty] res_ty matches
-tcMatchLambda :: MatchGroup Name -> BoxyRhoType -> TcM (ExprCoFn, MatchGroup TcId)
+tcMatchLambda :: MatchGroup Name -> BoxyRhoType -> TcM (HsWrapper, MatchGroup TcId)
tcMatchLambda match res_ty
= subFunTys doc n_pats res_ty $ \ pat_tys rhs_ty ->
tcMatches match_ctxt pat_tys rhs_ty match
= wrapLocM (tc_match ctxt pat_tys rhs_ty) match
where
tc_match ctxt pat_tys rhs_ty match@(Match pats maybe_rhs_sig grhss)
- = addErrCtxt (matchCtxt (mc_what ctxt) match) $
+ = add_match_ctxt match $
do { (pats', grhss') <- tcLamPats pats pat_tys rhs_ty $
tc_grhss ctxt maybe_rhs_sig grhss
; return (Match pats' Nothing grhss') }
<+> ppr res_sig)
; tcGRHSs ctxt grhss (co, rhs_ty) }
+ -- For (\x -> e), tcExpr has already said "In the expresssion \x->e"
+ -- so we don't want to add "In the lambda abstraction \x->e"
+ add_match_ctxt match thing_inside
+ = case mc_what ctxt of
+ LambdaExpr -> thing_inside
+ m_ctxt -> addErrCtxt (matchCtxt m_ctxt match) thing_inside
+
-------------
tcGRHSs :: TcMatchCtxt -> GRHSs Name -> (Refinement, BoxyRhoType)
-> TcM (GRHSs TcId)
= do { traceTc (text "tcBody" <+> ppr res_ty <+> ppr reft)
; let (co, res_ty') = refineResType reft res_ty
; body' <- tcPolyExpr body res_ty'
- ; return (mkLHsCoerce co body') }
+ ; return (mkLHsWrap co body') }
\end{code}
-- poly_id may have a polymorphic type
-- but mono_ty is just a monomorphic type variable
; co_fn <- tcSubExp (idType poly_id) mono_ty
- ; return (mkHsCoerce co_fn (HsVar poly_id)) }
+ ; return (mkHsWrap co_fn (HsVar poly_id)) }
tcMDoStmt tc_rhs ctxt stmt res_ty thing_inside
= pprPanic "tcMDoStmt: unexpected Stmt" (ppr stmt)