X-Git-Url: http://git.megacz.com/?p=ghc-hetmet.git;a=blobdiff_plain;f=compiler%2Ftypecheck%2FTcArrows.lhs;h=227c6ce923abded27256a736230495ac740d7553;hp=0b50b32e2411c259bf8a55d821ba5c70ed2a37b1;hb=b10d7d079ec9c3fc22d4700fe484dd297bddb805;hpb=d566d3ce56c583a74037e545312f30881b56f12e

diff --git a/compiler/typecheck/TcArrows.lhs b/compiler/typecheck/TcArrows.lhs
index 0b50b32..227c6ce 100644
--- a/compiler/typecheck/TcArrows.lhs
+++ b/compiler/typecheck/TcArrows.lhs
@@ -5,26 +5,15 @@
 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
 
 import {-# SOURCE #-}	TcExpr( tcMonoExpr, tcInferRho )
 
 import HsSyn
-import TcHsSyn
-
 import TcMatches
-
 import TcType
 import TcMType
 import TcBinds
-import TcSimplify
 import TcPat
 import TcUnify
 import TcRnMonad
@@ -34,7 +23,6 @@ import Name
 import TysWiredIn
 import VarSet 
 import TysPrim
-import Type
 
 import SrcLoc
 import Outputable
@@ -52,19 +40,18 @@ import Control.Monad
 
 \begin{code}
 tcProc :: InPat Name -> LHsCmdTop Name		-- proc pat -> expr
-       -> BoxyRhoType				-- Expected type of whole proc expression
+       -> TcRhoType				-- Expected type of whole proc expression
        -> TcM (OutPat TcId, LHsCmdTop TcId, CoercionI)
 
 tcProc pat cmd exp_ty
   = newArrowScope $
-    do	{ ((exp_ty1, res_ty), coi) <- boxySplitAppTy exp_ty 
-	; ((arr_ty, arg_ty), coi1) <- boxySplitAppTy exp_ty1
+    do	{ (coi, (exp_ty1, res_ty)) <- matchExpectedAppTy exp_ty 
+	; (coi1, (arr_ty, arg_ty)) <- matchExpectedAppTy exp_ty1
 	; let cmd_env = CmdEnv { cmd_arr = arr_ty }
-	; (pat', cmd') <- tcProcPat pat arg_ty res_ty $
-			  tcCmdTop cmd_env cmd []
-        ; let res_coi = mkTransCoI coi (mkAppTyCoI exp_ty1 coi1 res_ty IdCo)
-	; return (pat', cmd', res_coi) 
-        }
+	; (pat', cmd') <- tcPat ProcExpr pat arg_ty $
+			  tcCmdTop cmd_env cmd [] res_ty
+        ; let res_coi = mkTransCoI coi (mkAppTyCoI coi1 (IdCo res_ty))
+	; return (pat', cmd', res_coi) }
 \end{code}
 
 
@@ -117,6 +104,7 @@ 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') }
@@ -129,8 +117,7 @@ tc_cmd env (HsLet binds (L body_loc body)) res_ty
 
 tc_cmd env in_cmd@(HsCase scrut matches) (stk, res_ty)
   = addErrCtxt (cmdCtxt in_cmd) $ do
-      (scrut', scrut_ty) <- addErrCtxt (caseScrutCtxt scrut) $
-                              tcInferRho scrut 
+      (scrut', scrut_ty) <- tcInferRho scrut 
       matches' <- tcMatchesCase match_ctxt scrut_ty matches res_ty
       return (HsCase scrut' matches')
   where
@@ -184,9 +171,9 @@ 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)
@@ -194,8 +181,8 @@ 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		$
-			     tcLamPats pats cmd_stk res_ty	$
-			     tc_grhss grhss
+			     tcPats LambdaExpr pats cmd_stk	$
+			     tc_grhss grhss res_ty
 
 	; let match' = L mtch_loc (Match pats' Nothing grhss')
 	; return (HsLam (MatchGroup [match'] res_ty))
@@ -220,13 +207,12 @@ 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 res_ty $
+	; (stmts', body') <- tcStmts do_or_lc (tcMDoStmt tc_rhs) stmts res_ty $
 			     tcGuardedCmd env body []
 	; return (HsDo do_or_lc stmts' body' res_ty) }
   where
-    tc_stmt = tcMDoStmt tc_rhs
     tc_rhs rhs = do { ty <- newFlexiTyVarTy liftedTypeKind
 		    ; rhs' <- tcCmd env rhs ([], ty)
 		    ; return (rhs', ty) }
@@ -245,7 +231,6 @@ 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 [alphaTyVar]
 	; let w_ty = mkTyVarTy w_tv 	-- Just a convenient starting point
 
@@ -258,22 +243,15 @@ tc_cmd env cmd@(HsArrForm expr fixity cmd_args) (cmd_stk, res_ty)
 			      e_res_ty
 
 		-- Check expr
-	; (expr', lie) <- escapeArrowScope (getLIE (tcMonoExpr expr e_ty))
-	; 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)
-	; checkSigTyVarsWrt (tyVarsOfTypes (res_ty:cmd_stk)) [w_tv] 
+	; (inst_binds, expr') <- checkConstraints ArrowSkol [w_tv] [] $
+                                 escapeArrowScope (tcMonoExpr expr e_ty)
 
 		-- OK, now we are in a position to unscramble 
 		-- the s1..sm and check each cmd
 	; cmds' <- mapM (tc_cmd w_tv) cmds_w_tys
 
-	; return (HsArrForm (noLoc $ HsWrap (WpTyLam w_tv) 
-					       (unLoc $ mkHsDictLet inst_binds expr')) 
-			     fixity cmds')
-	}
+        ; let wrap = WpTyLam w_tv <.> mkWpLet inst_binds
+	; return (HsArrForm (mkLHsWrap wrap expr') fixity cmds') }
   where
  	-- Make the types	
 	--	b, ((e,s1) .. sm), s
@@ -303,20 +281,19 @@ tc_cmd env cmd@(HsArrForm expr fixity cmd_args) (cmd_stk, res_ty)
 
     unscramble :: TcType -> (TcType, [TcType])
     -- unscramble ((w,s1) .. sn)	=  (w, [s1..sn])
-    unscramble ty
+    unscramble ty = unscramble' ty []
+
+    unscramble' ty ss
        = case tcSplitTyConApp_maybe ty of
 	    Just (tc, [t,s]) | tc == pairTyCon 
-	       ->  let 
-		      (w,ss) = unscramble t  
-		   in (w, s:ss)
-				    
-	    other -> (ty, [])
+	       ->  unscramble' t (s:ss)
+	    _ -> (ty, ss)
 
 -----------------------------------------------------------------
 --		Base case for illegal commands
 -- This is where expressions that aren't commands get rejected
 
-tc_cmd env cmd _
+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}
@@ -330,6 +307,7 @@ tc_cmd env cmd _
 
 
 \begin{code}
+mkPairTy :: Type -> Type -> Type
 mkPairTy t1 t2 = mkTyConApp pairTyCon [t1,t2]
 
 arrowTyConKind :: Kind		--  *->*->*
@@ -344,20 +322,21 @@ arrowTyConKind = mkArrowKinds [liftedTypeKind, liftedTypeKind] liftedTypeKind
 %************************************************************************
 
 \begin{code}
+cmdCtxt :: HsExpr Name -> SDoc
 cmdCtxt cmd = ptext (sLit "In the command:") <+> ppr cmd
 
-caseScrutCtxt 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:"))
-	 4 (ppr cmd)
+       2 (ppr cmd)
 
+kappaUnderflow :: HsExpr Name -> SDoc
 kappaUnderflow cmd
   = hang (ptext (sLit "Command stack underflow at command:"))
-	 4 (ppr cmd)
+       2 (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')
+      2 (ptext (sLit "Argument type:") <+> ppr tup_ty')
 \end{code}