X-Git-Url: http://git.megacz.com/?p=ghc-hetmet.git;a=blobdiff_plain;f=compiler%2Ftypecheck%2FTcArrows.lhs;h=082f9da797ba1b3080c53d8c5c2547101d155ed3;hp=b53b5ea82156ab7d7857a9eb4302ee6a3aa8f654;hb=c1500e4888be2341c0b6e6897f494766c86feba0;hpb=e6d057711f4d6d6ff6342c39fa2b9e44d25447f1

diff --git a/compiler/typecheck/TcArrows.lhs b/compiler/typecheck/TcArrows.lhs
index b53b5ea..082f9da 100644
--- a/compiler/typecheck/TcArrows.lhs
+++ b/compiler/typecheck/TcArrows.lhs
@@ -1,42 +1,40 @@
 %
+% (c) The University of Glasgow 2006
 % (c) The GRASP/AQUA Project, Glasgow University, 1992-1998
 %
-\section{Typecheck arrow notation}
+Typecheck arrow notation
 
 \begin{code}
 module TcArrows ( tcProc ) where
 
-#include "HsVersions.h"
-
 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 TcGadt	( Refinement, emptyRefinement, refineResType )
-import TcPat	( tcLamPat, tcLamPats )
-import TcUnify	( checkSigTyVarsWrt, boxySplitAppTy )
+import TcHsSyn
+
+import TcMatches
+
+import TcType
+import TcMType
+import TcBinds
+import TcSimplify
+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(..), noLoc, unLoc )
+import SrcLoc
 import Outputable
-import Util	( lengthAtLeast )
+import FastString
+import Util
 
+import Control.Monad
 \end{code}
 
 %************************************************************************
@@ -48,16 +46,18 @@ 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') <- tcLamPat pat arg_ty (emptyRefinement, res_ty) $
+	; (pat', cmd') <- tcProcPat pat arg_ty res_ty $
 			  tcCmdTop cmd_env cmd []
-	; return (pat', cmd') }
+        ; let res_coi = mkTransCoI coi (mkAppTyCoI exp_ty1 coi1 res_ty IdCo)
+	; return (pat', cmd', res_coi) 
+        }
 \end{code}
 
 
@@ -81,27 +81,27 @@ mkCmdArrTy env t1 t2 = mkAppTys (cmd_arr env) [t1, t2]
 tcCmdTop :: CmdEnv 
          -> LHsCmdTop Name
          -> 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
+	 -> 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 reft_res_ty@(_,res_ty)
+tcCmdTop env (L loc (HsCmdTop cmd _ _ names)) cmd_stk res_ty
   = setSrcSpan loc $
-    do	{ cmd'   <- tcGuardedCmd env cmd cmd_stk reft_res_ty
+    do	{ cmd'   <- tcGuardedCmd env cmd cmd_stk 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)
+	     -> 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) }
+tcGuardedCmd env expr stk res_ty
+  = do	{ body <- tcCmd env expr (stk, res_ty)
+	; return body 
+        }
 
 tcCmd :: CmdEnv -> LHsExpr Name -> (CmdStack, TcTauType) -> TcM (LHsExpr TcId)
 	-- The main recursive function
@@ -110,6 +110,7 @@ tcCmd env (L loc expr) res_ty
 	{ expr' <- tc_cmd env expr res_ty
 	; return (L loc expr') }
 
+tc_cmd :: CmdEnv -> HsExpr Name -> (CmdStack, TcTauType) -> TcM (HsExpr TcId)
 tc_cmd env (HsPar cmd) res_ty
   = do	{ cmd' <- tcCmd env cmd res_ty
 	; return (HsPar cmd') }
@@ -121,12 +122,11 @@ tc_cmd env (HsLet binds (L body_loc body)) res_ty
 	; return (HsLet binds' (L body_loc body')) }
 
 tc_cmd env in_cmd@(HsCase scrut matches) (stk, res_ty)
-  = addErrCtxt (cmdCtxt in_cmd)		$
-    addErrCtxt (caseScrutCtxt scrut)	(
-      tcInferRho scrut 
-    )							`thenM`	\ (scrut', scrut_ty) ->
-    tcMatchesCase match_ctxt scrut_ty matches res_ty	`thenM`	\ matches' ->
-    returnM (HsCase scrut' matches')
+  = addErrCtxt (cmdCtxt in_cmd) $ do
+      (scrut', scrut_ty) <- addErrCtxt (caseScrutCtxt scrut) $
+                              tcInferRho scrut 
+      matches' <- tcMatchesCase match_ctxt scrut_ty matches res_ty
+      return (HsCase scrut' matches')
   where
     match_ctxt = MC { mc_what = CaseAlt,
                       mc_body = mc_body }
@@ -167,7 +167,6 @@ tc_cmd env cmd@(HsArrApp fun arg _ ho_app lr) (cmd_stk, res_ty)
 
 tc_cmd env cmd@(HsApp fun arg) (cmd_stk, res_ty)
   = addErrCtxt (cmdCtxt cmd)	$
--- gaw 2004 FIX?
     do  { arg_ty <- newFlexiTyVarTy openTypeKind
 
 	; fun' <- tcCmd env fun (arg_ty:cmd_stk, res_ty)
@@ -179,9 +178,9 @@ tc_cmd env cmd@(HsApp fun arg) (cmd_stk, res_ty)
 -------------------------------------------
 -- 		Lambda
 
-tc_cmd env cmd@(HsLam (MatchGroup [L mtch_loc (match@(Match pats maybe_rhs_sig grhss))] _))
+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)	$
+  = addErrCtxt (pprMatchInCtxt match_ctxt match)	$
 
     do	{ 	-- Check the cmd stack is big enough
 	; checkTc (lengthAtLeast cmd_stk n_pats)
@@ -199,7 +198,7 @@ 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
@@ -215,9 +214,9 @@ tc_cmd env cmd@(HsLam (MatchGroup [L mtch_loc (match@(Match pats maybe_rhs_sig g
 -------------------------------------------
 -- 		Do notation
 
-tc_cmd env cmd@(HsDo do_or_lc stmts body ty) (cmd_stk, res_ty)
+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 (emptyRefinement, res_ty) $
+	; (stmts', body') <- tcStmts do_or_lc tc_stmt stmts res_ty $
 			     tcGuardedCmd env body []
 	; return (HsDo do_or_lc stmts' body' res_ty) }
   where
@@ -240,8 +239,7 @@ tc_cmd env cmd@(HsDo do_or_lc stmts body ty) (cmd_stk, res_ty)
 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
@@ -254,7 +252,8 @@ 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)
@@ -264,7 +263,7 @@ 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 (noLoc $ HsWrap (WpTyLam w_tv) 
+	; return (HsArrForm (noLoc $ HsWrap (WpTyLam w_tv) 
 					       (unLoc $ mkHsDictLet inst_binds expr')) 
 			     fixity cmds')
 	}
@@ -293,7 +292,7 @@ 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 (emptyRefinement, s) }
+	   ; tcCmdTop (env { cmd_arr = b }) cmd arg_tys s }
 
     unscramble :: TcType -> (TcType, [TcType])
     -- unscramble ((w,s1) .. sn)	=  (w, [s1..sn])
@@ -304,17 +303,15 @@ tc_cmd env cmd@(HsArrForm expr fixity cmd_args) (cmd_stk, res_ty)
 		      (w,ss) = unscramble t  
 		   in (w, s:ss)
 				    
-	    other -> (ty, [])
-
-    sig_msg  = ptext SLIT("expected type of a command form")
+	    _ -> (ty, [])
 
 -----------------------------------------------------------------
 --		Base case for illegal commands
 -- This is where expressions that aren't commands get rejected
 
-tc_cmd env cmd _
-  = failWithTc (vcat [ptext SLIT("The expression"), nest 2 (ppr cmd), 
-		      ptext SLIT("was found where an arrow command was expected")])
+tc_cmd _ cmd _
+  = failWithTc (vcat [ptext (sLit "The expression"), nest 2 (ppr cmd), 
+		      ptext (sLit "was found where an arrow command was expected")])
 \end{code}
 
 
@@ -326,6 +323,7 @@ tc_cmd env cmd _
 
 
 \begin{code}
+mkPairTy :: Type -> Type -> Type
 mkPairTy t1 t2 = mkTyConApp pairTyCon [t1,t2]
 
 arrowTyConKind :: Kind		--  *->*->*
@@ -340,20 +338,25 @@ arrowTyConKind = mkArrowKinds [liftedTypeKind, liftedTypeKind] liftedTypeKind
 %************************************************************************
 
 \begin{code}
-cmdCtxt cmd = ptext SLIT("In the command:") <+> ppr cmd
+cmdCtxt :: HsExpr Name -> SDoc
+cmdCtxt cmd = ptext (sLit "In the command:") <+> ppr cmd
 
+caseScrutCtxt :: LHsExpr Name -> SDoc
 caseScrutCtxt cmd
-  = hang (ptext SLIT("In the scrutinee of a case command:")) 4 (ppr cmd)
+  = hang (ptext (sLit "In the scrutinee of a case command:")) 4 (ppr cmd)
 
+nonEmptyCmdStkErr :: HsExpr Name -> SDoc
 nonEmptyCmdStkErr cmd
-  = hang (ptext SLIT("Non-empty command stack at command:"))
+  = hang (ptext (sLit "Non-empty command stack at command:"))
 	 4 (ppr cmd)
 
+kappaUnderflow :: HsExpr Name -> SDoc
 kappaUnderflow cmd
-  = hang (ptext SLIT("Command stack underflow at command:"))
+  = hang (ptext (sLit "Command stack underflow at command:"))
 	 4 (ppr cmd)
 
+badFormFun :: Int -> TcType -> SDoc
 badFormFun i tup_ty'
- = hang (ptext SLIT("The type of the") <+> speakNth i <+> ptext SLIT("argument of a command form has the wrong shape"))
-	4 (ptext SLIT("Argument type:") <+> ppr tup_ty')
+ = hang (ptext (sLit "The type of the") <+> speakNth i <+> ptext (sLit "argument of a command form has the wrong shape"))
+	4 (ptext (sLit "Argument type:") <+> ppr tup_ty')
 \end{code}