X-Git-Url: http://git.megacz.com/?p=ghc-hetmet.git;a=blobdiff_plain;f=compiler%2Ftypecheck%2FTcMatches.lhs;h=452bae792d2c8521f4a91ad1b925cc4d0e7f74e0;hp=da1d0e017df82ff85b3e471d00e07f07119bfd73;hb=58de6cb725982dd1f57803cc838f233d5fd9c42c;hpb=1d1c3c727617630beacacaf33022e1daba06a0bb diff --git a/compiler/typecheck/TcMatches.lhs b/compiler/typecheck/TcMatches.lhs index da1d0e0..452bae7 100644 --- a/compiler/typecheck/TcMatches.lhs +++ b/compiler/typecheck/TcMatches.lhs @@ -39,8 +39,12 @@ import TysWiredIn import PrelNames import Id import TyCon +import TysPrim import Outputable +import Util import SrcLoc + +import Control.Monad \end{code} %************************************************************************ @@ -193,9 +197,9 @@ tcGRHSs :: TcMatchCtxt -> GRHSs Name -> (Refinement, BoxyRhoType) tcGRHSs ctxt (GRHSs grhss binds) res_ty = do { (binds', grhss') <- tcLocalBinds binds $ - mappM (wrapLocM (tcGRHS ctxt res_ty)) grhss + mapM (wrapLocM (tcGRHS ctxt res_ty)) grhss - ; returnM (GRHSs grhss' binds') } + ; return (GRHSs grhss' binds') } ------------- tcGRHS :: TcMatchCtxt -> (Refinement, BoxyRhoType) -> GRHS Name -> TcM (GRHS TcId) @@ -391,16 +395,79 @@ tcLcStmt m_tc ctxt (ParStmt bndr_stmts_s) elt_ty thing_inside ; return (ids, pairs', thing) } ; return ( (stmts', ids) : pairs', thing ) } +tcLcStmt m_tc ctxt (TransformStmt (stmts, binders) usingExpr maybeByExpr) elt_ty thing_inside = do + (stmts', (binders', usingExpr', maybeByExpr', thing)) <- + tcStmts (TransformStmtCtxt ctxt) (tcLcStmt m_tc) stmts elt_ty $ \elt_ty' -> do + let alphaListTy = mkTyConApp m_tc [alphaTy] + + (usingExpr', maybeByExpr') <- + case maybeByExpr of + Nothing -> do + -- We must validate that usingExpr :: forall a. [a] -> [a] + usingExpr' <- tcPolyExpr usingExpr (mkForAllTy alphaTyVar (alphaListTy `mkFunTy` alphaListTy)) + return (usingExpr', Nothing) + Just byExpr -> do + -- We must infer a type such that e :: t and then check that usingExpr :: forall a. (a -> t) -> [a] -> [a] + (byExpr', tTy) <- tcInferRho byExpr + usingExpr' <- tcPolyExpr usingExpr (mkForAllTy alphaTyVar ((alphaTy `mkFunTy` tTy) `mkFunTy` (alphaListTy `mkFunTy` alphaListTy))) + return (usingExpr', Just byExpr') + + binders' <- tcLookupLocalIds binders + thing <- thing_inside elt_ty' + + return (binders', usingExpr', maybeByExpr', thing) + + return (TransformStmt (stmts', binders') usingExpr' maybeByExpr', thing) + +tcLcStmt m_tc ctxt (GroupStmt (stmts, bindersMap) groupByClause) elt_ty thing_inside = do + (stmts', (bindersMap', groupByClause', thing)) <- + tcStmts (TransformStmtCtxt ctxt) (tcLcStmt m_tc) stmts elt_ty $ \elt_ty' -> do + let alphaListTy = mkTyConApp m_tc [alphaTy] + alphaListListTy = mkTyConApp m_tc [alphaListTy] + + groupByClause' <- + case groupByClause of + GroupByNothing usingExpr -> + -- We must validate that usingExpr :: forall a. [a] -> [[a]] + tcPolyExpr usingExpr (mkForAllTy alphaTyVar (alphaListTy `mkFunTy` alphaListListTy)) >>= (return . GroupByNothing) + GroupBySomething eitherUsingExpr byExpr -> do + -- We must infer a type such that byExpr :: t + (byExpr', tTy) <- tcInferRho byExpr + + -- If it exists, we then check that usingExpr :: forall a. (a -> t) -> [a] -> [[a]] + let expectedUsingType = mkForAllTy alphaTyVar ((alphaTy `mkFunTy` tTy) `mkFunTy` (alphaListTy `mkFunTy` alphaListListTy)) + eitherUsingExpr' <- + case eitherUsingExpr of + Left usingExpr -> (tcPolyExpr usingExpr expectedUsingType) >>= (return . Left) + Right usingExpr -> (tcPolyExpr (noLoc usingExpr) expectedUsingType) >>= (return . Right . unLoc) + return $ GroupBySomething eitherUsingExpr' byExpr' + + -- Find the IDs and types of all old binders + let (oldBinders, newBinders) = unzip bindersMap + oldBinders' <- tcLookupLocalIds oldBinders + + -- Ensure that every old binder of type b is linked up with its new binder which should have type [b] + let newBinders' = zipWith associateNewBinder oldBinders' newBinders + + -- Type check the thing in the environment with these new binders and return the result + thing <- tcExtendIdEnv newBinders' (thing_inside elt_ty') + return (zipEqual "tcLcStmt: Old and new binder lists were not of the same length" oldBinders' newBinders', groupByClause', thing) + + return (GroupStmt (stmts', bindersMap') groupByClause', thing) + where + associateNewBinder :: TcId -> Name -> TcId + associateNewBinder oldBinder newBinder = mkLocalId newBinder (mkTyConApp m_tc [idType oldBinder]) + tcLcStmt m_tc ctxt stmt elt_ty thing_inside = pprPanic "tcLcStmt: unexpected Stmt" (ppr stmt) - + -------------------------------- -- Do-notation -- The main excitement here is dealing with rebindable syntax tcDoStmt :: TcStmtChecker -tcDoStmt ctxt (BindStmt pat rhs bind_op fail_op) reft_res_ty@(_,res_ty) thing_inside +tcDoStmt ctxt (BindStmt pat rhs bind_op fail_op) (reft,res_ty) thing_inside = do { (rhs', rhs_ty) <- tcInferRho rhs -- We should use type *inference* for the RHS computations, becuase of GADTs. -- do { pat <- rhs; } @@ -409,33 +476,44 @@ tcDoStmt ctxt (BindStmt pat rhs bind_op fail_op) reft_res_ty@(_,res_ty) thing_in -- We do inference on rhs, so that information about its type can be refined -- when type-checking the pattern. - -- Deal with rebindable syntax; (>>=) :: rhs_ty -> (a -> res_ty) -> res_ty - ; (bind_op', pat_ty) <- + -- Deal with rebindable syntax: + -- (>>=) :: rhs_ty -> (pat_ty -> new_res_ty) -> res_ty + -- This level of generality is needed for using do-notation + -- in full generality; see Trac #1537 + ; ((bind_op', new_res_ty), pat_ty) <- withBox liftedTypeKind $ \ pat_ty -> + withBox liftedTypeKind $ \ new_res_ty -> tcSyntaxOp DoOrigin bind_op - (mkFunTys [rhs_ty, mkFunTy pat_ty res_ty] res_ty) + (mkFunTys [rhs_ty, mkFunTy pat_ty new_res_ty] res_ty) -- If (but only if) the pattern can fail, -- typecheck the 'fail' operator ; fail_op' <- if isIrrefutableHsPat pat then return noSyntaxExpr - else tcSyntaxOp DoOrigin fail_op (mkFunTy stringTy res_ty) + else tcSyntaxOp DoOrigin fail_op (mkFunTy stringTy new_res_ty) - ; (pat', thing) <- tcLamPat pat pat_ty reft_res_ty thing_inside + ; (pat', thing) <- tcLamPat pat pat_ty (reft, new_res_ty) thing_inside ; return (BindStmt pat' rhs' bind_op' fail_op', thing) } -tcDoStmt ctxt (ExprStmt rhs then_op _) reft_res_ty@(_,res_ty) thing_inside +tcDoStmt ctxt (ExprStmt rhs then_op _) (reft,res_ty) thing_inside = do { (rhs', rhs_ty) <- tcInferRho rhs - -- Deal with rebindable syntax; (>>) :: rhs_ty -> res_ty -> res_ty - ; then_op' <- tcSyntaxOp DoOrigin then_op - (mkFunTys [rhs_ty, res_ty] res_ty) + -- Deal with rebindable syntax; (>>) :: rhs_ty -> new_res_ty -> res_ty + ; (then_op', new_res_ty) <- + withBox liftedTypeKind $ \ new_res_ty -> + tcSyntaxOp DoOrigin then_op + (mkFunTys [rhs_ty, new_res_ty] res_ty) - ; thing <- thing_inside reft_res_ty + ; thing <- thing_inside (reft, new_res_ty) ; return (ExprStmt rhs' then_op' rhs_ty, thing) } +tcDoStmt ctxt (RecStmt {}) res_ty thing_inside + = failWithTc (ptext SLIT("Illegal 'rec' stmt in") <+> pprStmtContext ctxt) + -- This case can't be caught in the renamer + -- see RnExpr.checkRecStmt + tcDoStmt ctxt stmt res_ty thing_inside = pprPanic "tcDoStmt: unexpected Stmt" (ppr stmt)