X-Git-Url: http://git.megacz.com/?p=ghc-hetmet.git;a=blobdiff_plain;f=compiler%2Ftypecheck%2FTcArrows.lhs;h=0055d6453feb9f0f60fe7f8a2f8aca2cfae322ac;hp=3bfa9b4757f0819a346c2a6ac4df438460fa0e98;hb=6a05ec5ef5373f61b7f9f5bdc344483417fa801b;hpb=0065d5ab628975892cea1ec7303f968c3338cbe1

diff --git a/compiler/typecheck/TcArrows.lhs b/compiler/typecheck/TcArrows.lhs
index 3bfa9b4..0055d64 100644
--- a/compiler/typecheck/TcArrows.lhs
+++ b/compiler/typecheck/TcArrows.lhs
@@ -1,9 +1,17 @@
 %
+% (c) The University of Glasgow 2006
 % (c) The GRASP/AQUA Project, Glasgow University, 1992-1998
 %
-\section{Typecheck arrow notation}
+Typecheck arrow notation
 
 \begin{code}
+{-# OPTIONS -w #-}
+-- The above warning supression flag is a temporary kludge.
+-- While working on this module you are encouraged to remove it and fix
+-- any warnings in the module. See
+--     http://hackage.haskell.org/trac/ghc/wiki/Commentary/CodingStyle#Warnings
+-- for details
+
 module TcArrows ( tcProc ) where
 
 #include "HsVersions.h"
@@ -11,31 +19,29 @@ module TcArrows ( tcProc ) where
 import {-# SOURCE #-}	TcExpr( tcMonoExpr, tcInferRho )
 
 import HsSyn
-import TcHsSyn	(  mkHsDictLet )
-
-import TcMatches ( matchCtxt, tcStmts, tcMDoStmt, tcGuardStmt,
-		   TcMatchCtxt(..), tcMatchesCase )
-
-import TcType	( TcType, TcTauType, BoxyRhoType, mkFunTys, mkTyConApp,
-		  mkTyVarTy, mkAppTys, tcSplitTyConApp_maybe, tcEqType, 
-		  SkolemInfo(..) )
-import TcMType	( newFlexiTyVarTy, tcInstSkolTyVars, zonkTcType )
-import TcBinds	( tcLocalBinds )
-import TcSimplify ( tcSimplifyCheck )
-import TcPat	( tcPat, tcPats, PatCtxt(..) )
-import TcUnify	( checkSigTyVarsWrt, boxySplitAppTy )
+import TcHsSyn
+
+import TcMatches
+
+import TcType
+import TcMType
+import TcBinds
+import TcSimplify
+import TcGadt
+import TcPat
+import TcUnify
 import TcRnMonad
-import Inst	( tcSyntaxName )
-import Name	( Name )
-import TysWiredIn ( boolTy, pairTyCon )
+import Coercion
+import Inst
+import Name
+import TysWiredIn
 import VarSet 
-import TysPrim	( alphaTyVar )
-import Type	( Kind, mkArrowKinds, liftedTypeKind, openTypeKind, tyVarsOfTypes )
+import TysPrim
+import Type
 
-import SrcLoc	( Located(..) )
+import SrcLoc
 import Outputable
-import Util	( lengthAtLeast )
-
+import Util
 \end{code}
 
 %************************************************************************
@@ -47,16 +53,18 @@ import Util	( lengthAtLeast )
 \begin{code}
 tcProc :: InPat Name -> LHsCmdTop Name		-- proc pat -> expr
        -> BoxyRhoType				-- Expected type of whole proc expression
-       -> TcM (OutPat TcId, LHsCmdTop TcId)
+       -> TcM (OutPat TcId, LHsCmdTop TcId, CoercionI)
 
 tcProc pat cmd exp_ty
   = newArrowScope $
-    do	{ (exp_ty1, res_ty) <- boxySplitAppTy exp_ty 
-	; (arr_ty, arg_ty)  <- boxySplitAppTy exp_ty1
+    do	{ ((exp_ty1, res_ty), coi) <- boxySplitAppTy exp_ty 
+	; ((arr_ty, arg_ty), coi1) <- boxySplitAppTy exp_ty1
 	; let cmd_env = CmdEnv { cmd_arr = arr_ty }
-	; (pat', cmd') <- tcPat LamPat pat arg_ty res_ty $ \ res_ty' ->
-			  tcCmdTop cmd_env cmd ([], res_ty')
-	; return (pat', cmd') }
+	; (pat', cmd') <- tcLamPat pat arg_ty (emptyRefinement, res_ty) $
+			  tcCmdTop cmd_env cmd []
+        ; let res_coi = mkTransCoI coi (mkAppTyCoI exp_ty1 coi1 res_ty IdCo)
+	; return (pat', cmd', res_coi) 
+        }
 \end{code}
 
 
@@ -79,20 +87,29 @@ mkCmdArrTy env t1 t2 = mkAppTys (cmd_arr env) [t1, t2]
 ---------------------------------------
 tcCmdTop :: CmdEnv 
          -> LHsCmdTop Name
-         -> (CmdStack, TcTauType)	-- Expected result type; always a monotype
+         -> CmdStack
+	 -> (Refinement, TcTauType)	-- Expected result type; always a monotype
 					-- We know exactly how many cmd args are expected,
 					-- albeit perhaps not their types; so we can pass 
 					-- in a CmdStack
         -> TcM (LHsCmdTop TcId)
 
-tcCmdTop env (L loc (HsCmdTop cmd _ _ names)) (cmd_stk, res_ty)
+tcCmdTop env (L loc (HsCmdTop cmd _ _ names)) cmd_stk reft_res_ty@(_,res_ty)
   = setSrcSpan loc $
-    do	{ cmd'   <- tcCmd env cmd (cmd_stk, res_ty)
+    do	{ cmd'   <- tcGuardedCmd env cmd cmd_stk reft_res_ty
 	; names' <- mapM (tcSyntaxName ProcOrigin (cmd_arr env)) names
 	; return (L loc $ HsCmdTop cmd' cmd_stk res_ty names') }
 
 
 ----------------------------------------
+tcGuardedCmd :: CmdEnv -> LHsExpr Name -> CmdStack
+	     -> (Refinement, TcTauType) -> TcM (LHsExpr TcId)
+-- A wrapper that deals with the refinement (if any)
+tcGuardedCmd env expr stk (reft, res_ty)
+  = do	{ let (co, res_ty') = refineResType reft res_ty
+    	; body <- tcCmd env expr (stk, res_ty')
+	; return (mkLHsWrap co body) }
+
 tcCmd :: CmdEnv -> LHsExpr Name -> (CmdStack, TcTauType) -> TcM (LHsExpr TcId)
 	-- The main recursive function
 tcCmd env (L loc expr) res_ty
@@ -120,7 +137,7 @@ tc_cmd env in_cmd@(HsCase scrut matches) (stk, res_ty)
   where
     match_ctxt = MC { mc_what = CaseAlt,
                       mc_body = mc_body }
-    mc_body body res_ty' = tcCmd env body (stk, res_ty')
+    mc_body body res_ty' = tcGuardedCmd env body stk res_ty'
 
 tc_cmd env (HsIf pred b1 b2) res_ty
   = do 	{ pred' <- tcMonoExpr pred boolTy
@@ -169,7 +186,6 @@ tc_cmd env cmd@(HsApp fun arg) (cmd_stk, res_ty)
 -------------------------------------------
 -- 		Lambda
 
--- gaw 2004
 tc_cmd env cmd@(HsLam (MatchGroup [L mtch_loc (match@(Match pats maybe_rhs_sig grhss))] _))
        (cmd_stk, res_ty)
   = addErrCtxt (matchCtxt match_ctxt match)	$
@@ -180,7 +196,7 @@ tc_cmd env cmd@(HsLam (MatchGroup [L mtch_loc (match@(Match pats maybe_rhs_sig g
 
 		-- Check the patterns, and the GRHSs inside
 	; (pats', grhss') <- setSrcSpan mtch_loc		$
-			     tcPats LamPat pats cmd_stk res_ty	$
+			     tcLamPats pats cmd_stk res_ty	$
 			     tc_grhss grhss
 
 	; let match' = L mtch_loc (Match pats' Nothing grhss')
@@ -190,7 +206,7 @@ tc_cmd env cmd@(HsLam (MatchGroup [L mtch_loc (match@(Match pats maybe_rhs_sig g
   where
     n_pats     = length pats
     stk'       = drop n_pats cmd_stk
-    match_ctxt = LambdaExpr 	-- Maybe KappaExpr?
+    match_ctxt = (LambdaExpr :: HsMatchContext Name)	-- Maybe KappaExpr?
     pg_ctxt    = PatGuard match_ctxt
 
     tc_grhss (GRHSs grhss binds) res_ty
@@ -199,9 +215,8 @@ tc_cmd env cmd@(HsLam (MatchGroup [L mtch_loc (match@(Match pats maybe_rhs_sig g
 	     ; return (GRHSs grhss' binds') }
 
     tc_grhs res_ty (GRHS guards body)
-	= do { (guards', rhs') <- tcStmts pg_ctxt tcGuardStmt
-					  guards res_ty
-					  (\res_ty' -> tcCmd env body (stk', res_ty'))
+	= do { (guards', rhs') <- tcStmts pg_ctxt tcGuardStmt guards res_ty $
+				  tcGuardedCmd env body stk'
 	     ; return (GRHS guards' rhs') }
 
 -------------------------------------------
@@ -209,8 +224,8 @@ tc_cmd env cmd@(HsLam (MatchGroup [L mtch_loc (match@(Match pats maybe_rhs_sig g
 
 tc_cmd env cmd@(HsDo do_or_lc stmts body ty) (cmd_stk, res_ty)
   = do 	{ checkTc (null cmd_stk) (nonEmptyCmdStkErr cmd)
-	; (stmts', body') <- tcStmts do_or_lc tc_stmt stmts res_ty $ \ res_ty' ->
-			     tcCmd env body ([], res_ty')
+	; (stmts', body') <- tcStmts do_or_lc tc_stmt stmts (emptyRefinement, res_ty) $
+			     tcGuardedCmd env body []
 	; return (HsDo do_or_lc stmts' body' res_ty) }
   where
     tc_stmt = tcMDoStmt tc_rhs
@@ -233,7 +248,7 @@ tc_cmd env cmd@(HsArrForm expr fixity cmd_args) (cmd_stk, res_ty)
   = addErrCtxt (cmdCtxt cmd)	$
     do	{ cmds_w_tys <- zipWithM new_cmd_ty cmd_args [1..]
 	; span       <- getSrcSpanM
-	; [w_tv]     <- tcInstSkolTyVars (ArrowSkol span) [alphaTyVar]
+	; [w_tv]     <- tcInstSkolTyVars ArrowSkol [alphaTyVar]
 	; let w_ty = mkTyVarTy w_tv 	-- Just a convenient starting point
 
 		--  a ((w,t1) .. tn) t
@@ -246,7 +261,8 @@ tc_cmd env cmd@(HsArrForm expr fixity cmd_args) (cmd_stk, res_ty)
 
 		-- Check expr
 	; (expr', lie) <- escapeArrowScope (getLIE (tcMonoExpr expr e_ty))
-	; inst_binds <- tcSimplifyCheck sig_msg [w_tv] [] lie
+	; loc <- getInstLoc (SigOrigin ArrowSkol)
+	; inst_binds <- tcSimplifyCheck loc [w_tv] [] lie
 
 		-- Check that the polymorphic variable hasn't been unified with anything
 		-- and is not free in res_ty or the cmd_stk  (i.e.  t, t1..tn)
@@ -256,7 +272,9 @@ tc_cmd env cmd@(HsArrForm expr fixity cmd_args) (cmd_stk, res_ty)
 		-- the s1..sm and check each cmd
 	; cmds' <- mapM (tc_cmd w_tv) cmds_w_tys
 
-	; returnM (HsArrForm (mkHsTyLam [w_tv] (mkHsDictLet inst_binds expr')) fixity cmds')
+	; returnM (HsArrForm (noLoc $ HsWrap (WpTyLam w_tv) 
+					       (unLoc $ mkHsDictLet inst_binds expr')) 
+			     fixity cmds')
 	}
   where
  	-- Make the types	
@@ -264,7 +282,6 @@ tc_cmd env cmd@(HsArrForm expr fixity cmd_args) (cmd_stk, res_ty)
     new_cmd_ty :: LHsCmdTop Name -> Int
 	       -> TcM (LHsCmdTop Name, Int, TcType, TcType, TcType)
     new_cmd_ty cmd i
--- gaw 2004 FIX?
 	  = do	{ b_ty   <- newFlexiTyVarTy arrowTyConKind
 		; tup_ty <- newFlexiTyVarTy liftedTypeKind
 			-- We actually make a type variable for the tuple
@@ -284,7 +301,7 @@ tc_cmd env cmd@(HsArrForm expr fixity cmd_args) (cmd_stk, res_ty)
 		      not (w_tv `elemVarSet` tyVarsOfTypes arg_tys))
 		     (badFormFun i tup_ty')
 
-	   ; tcCmdTop (env { cmd_arr = b }) cmd (arg_tys, s) }
+	   ; tcCmdTop (env { cmd_arr = b }) cmd arg_tys (emptyRefinement, s) }
 
     unscramble :: TcType -> (TcType, [TcType])
     -- unscramble ((w,s1) .. sn)	=  (w, [s1..sn])
@@ -297,8 +314,6 @@ tc_cmd env cmd@(HsArrForm expr fixity cmd_args) (cmd_stk, res_ty)
 				    
 	    other -> (ty, [])
 
-    sig_msg  = ptext SLIT("expected type of a command form")
-
 -----------------------------------------------------------------
 --		Base case for illegal commands
 -- This is where expressions that aren't commands get rejected