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[ghc-hetmet.git] / compiler / typecheck / TcArrows.lhs

diff --git a/compiler/typecheck/TcArrows.lhs b/compiler/typecheck/TcArrows.lhs
index b4afcaf..0055d64 100644 (file)
--- 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"
@@ -11,32 +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 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 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(..), noLoc, unLoc )
+import SrcLoc
 import Outputable
-import Util    ( lengthAtLeast )
-
+import Util
 \end{code}
 
 %************************************************************************
@@ -48,16 +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') <- tcLamPat pat arg_ty (emptyRefinement, 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}
 
 
@@ -101,7 +108,7 @@ tcGuardedCmd :: CmdEnv -> LHsExpr Name -> CmdStack
 tcGuardedCmd env expr stk (reft, res_ty)
   = do { let (co, res_ty') = refineResType reft res_ty
        ; body <- tcCmd env expr (stk, res_ty')
-       ; return (mkLHsCoerce co body) }
+       ; return (mkLHsWrap co body) }
 
 tcCmd :: CmdEnv -> LHsExpr Name -> (CmdStack, TcTauType) -> TcM (LHsExpr TcId)
        -- The main recursive function
@@ -199,7 +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
@@ -241,7 +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
@@ -254,7 +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)
@@ -264,7 +272,7 @@ 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 $ HsCoerce (CoTyLams [w_tv]) 
+       ; returnM (HsArrForm (noLoc $ HsWrap (WpTyLam w_tv) 
                                               (unLoc $ mkHsDictLet inst_binds expr')) 
                             fixity cmds')
        }
@@ -306,8 +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