Fix Trac #2310: result type signatures are not supported any more

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

diff --git a/compiler/typecheck/TcArrows.lhs b/compiler/typecheck/TcArrows.lhs
index 90a5e88..082f9da 100644 (file)
--- a/compiler/typecheck/TcArrows.lhs
+++ b/compiler/typecheck/TcArrows.lhs
@@ -5,17 +5,8 @@
 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"
-
 import {-# SOURCE #-}  TcExpr( tcMonoExpr, tcInferRho )
 
 import HsSyn
@@ -40,6 +31,7 @@ import Type
 
 import SrcLoc
 import Outputable
+import FastString
 import Util
 
 import Control.Monad
@@ -118,6 +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') }
@@ -185,9 +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)
@@ -221,7 +214,7 @@ 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 $
                             tcGuardedCmd env body []
@@ -246,7 +239,6 @@ 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
 
@@ -311,15 +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, [])
+           _ -> (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}
 
 
@@ -331,6 +323,7 @@ tc_cmd env cmd _
 
 
 \begin{code}
+mkPairTy :: Type -> Type -> Type
 mkPairTy t1 t2 = mkTyConApp pairTyCon [t1,t2]
 
 arrowTyConKind :: Kind         --  *->*->*
@@ -345,20 +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}