From 82b61ac8e14df43f84afc20c6f6691f433f07951 Mon Sep 17 00:00:00 2001
From: Ian Lynagh <igloo@earth.li>
Date: Fri, 10 Jul 2009 00:56:38 +0000
Subject: [PATCH] Fix some "warn-unused-do-bind" warnings where we just want
 to ignore the result

---
 Control/Exception/Base.hs  |    6 +++---
 GHC/IO/Encoding/Iconv.hs   |    3 +--
 GHC/IO/FD.hs               |   21 ++++++++++-----------
 GHC/IO/Handle/Internals.hs |    2 +-
 4 files changed, 15 insertions(+), 17 deletions(-)

diff --git a/Control/Exception/Base.hs b/Control/Exception/Base.hs
index d5cac44..06c5390 100644
--- a/Control/Exception/Base.hs
+++ b/Control/Exception/Base.hs
@@ -474,7 +474,7 @@ tryJust p a = do
 -- | Like 'finally', but only performs the final action if there was an
 -- exception raised by the computation.
 onException :: IO a -> IO b -> IO a
-onException io what = io `catch` \e -> do what
+onException io what = io `catch` \e -> do _ <- what
                                           throw (e :: SomeException)
 
 -----------------------------------------------------------------------------
@@ -509,7 +509,7 @@ bracket before after thing =
   block (do
     a <- before
     r <- unblock (thing a) `onException` after a
-    after a
+    _ <- after a
     return r
  )
 #endif
@@ -524,7 +524,7 @@ finally :: IO a         -- ^ computation to run first
 a `finally` sequel =
   block (do
     r <- unblock a `onException` sequel
-    sequel
+    _ <- sequel
     return r
   )
 
diff --git a/GHC/IO/Encoding/Iconv.hs b/GHC/IO/Encoding/Iconv.hs
index b8fcfd9..02090d1 100644
--- a/GHC/IO/Encoding/Iconv.hs
+++ b/GHC/IO/Encoding/Iconv.hs
@@ -151,8 +151,7 @@ newIConv from to fn =
   withCString from $ \ from_str ->
   withCString to   $ \ to_str -> do
     iconvt <- throwErrnoIfMinus1 "mkTextEncoding" $ hs_iconv_open to_str from_str
-    let iclose = do throwErrnoIfMinus1 "Iconv.close" $ hs_iconv_close iconvt
-                    return ()
+    let iclose = throwErrnoIfMinus1_ "Iconv.close" $ hs_iconv_close iconvt
     return BufferCodec{
                 encode = fn iconvt,
                 close  = iclose,
diff --git a/GHC/IO/FD.hs b/GHC/IO/FD.hs
index 8e52584..2b21914 100644
--- a/GHC/IO/FD.hs
+++ b/GHC/IO/FD.hs
@@ -165,7 +165,8 @@ openFile filepath iomode =
     (fD,fd_type) <- mkFD fd iomode Nothing{-no stat-}
                             False{-not a socket-} 
                             True{-is non-blocking-}
-            `catchAny` \e -> do c_close fd; throwIO e
+            `catchAny` \e -> do _ <- c_close fd
+                                throwIO e
 
 #ifndef mingw32_HOST_OS
         -- we want to truncate() if this is an open in WriteMode, but only
@@ -292,12 +293,12 @@ close fd =
        c_close (fdFD fd)
 
 release :: FD -> IO ()
-release fd = do
-#ifndef mingw32_HOST_OS
-   unlockFile (fdFD fd)
+#ifdef mingw32_HOST_OS
+release _ = return ()
+#else
+release fd = do _ <- unlockFile (fdFD fd)
+                return ()
 #endif
-   let _ = fd -- warning suppression
-   return ()
 
 #ifdef mingw32_HOST_OS
 foreign import stdcall unsafe "HsBase.h closesocket"
@@ -311,9 +312,8 @@ isSeekable fd = do
 
 seek :: FD -> SeekMode -> Integer -> IO ()
 seek fd mode off = do
-  throwErrnoIfMinus1Retry "seek" $
+  throwErrnoIfMinus1Retry_ "seek" $
      c_lseek (fdFD fd) (fromIntegral off) seektype
-  return ()
  where
     seektype :: CInt
     seektype = case mode of
@@ -332,9 +332,8 @@ getSize fd = fdFileSize (fdFD fd)
 
 setSize :: FD -> Integer -> IO () 
 setSize fd size = do
-  throwErrnoIf (/=0) "GHC.IO.FD.setSize"  $
+  throwErrnoIf_ (/=0) "GHC.IO.FD.setSize"  $
      c_ftruncate (fdFD fd) (fromIntegral size)
-  return ()
 
 devType :: FD -> IO IODeviceType
 devType fd = do (ty,_,_) <- fdStat (fdFD fd); return ty
@@ -347,7 +346,7 @@ dup fd = do
 dup2 :: FD -> FD -> IO FD
 dup2 fd fdto = do
   -- Windows' dup2 does not return the new descriptor, unlike Unix
-  throwErrnoIfMinus1 "GHC.IO.FD.dup2" $ 
+  throwErrnoIfMinus1_ "GHC.IO.FD.dup2" $
     c_dup2 (fdFD fd) (fdFD fdto)
   return fd{ fdFD = fdFD fdto } -- original FD, with the new fdFD
 
diff --git a/GHC/IO/Handle/Internals.hs b/GHC/IO/Handle/Internals.hs
index fc9fbde..6fb66c7 100644
--- a/GHC/IO/Handle/Internals.hs
+++ b/GHC/IO/Handle/Internals.hs
@@ -334,7 +334,7 @@ handleFinalizer fp m = do
       _ -> do flushWriteBuffer handle_ `catchAny` \_ -> return ()
                 -- ignore errors and async exceptions, and close the
                 -- descriptor anyway...
-              hClose_handle_ handle_
+              _ <- hClose_handle_ handle_
               return ()
   putMVar m (ioe_finalizedHandle fp)
 
-- 
1.7.10.4