compiler/specialise/Rules.hs

@@ -739,9 +739,13 @@ match_co renv subst (TyConAppCo r1 tc1 cos1) co2
          | r1 == r2 && tc1 == tc2
          -> match_cos renv subst cos1 cos2
        _ -> Nothing
-match_co _ _ co1 co2
-  = pprTrace "match_co: needs more cases" (ppr co1 $$ ppr co2) Nothing
+match_co _ _ _co1 _co2
     -- Currently just deals with CoVarCo, TyConAppCo and Refl
+#ifdef DEBUG
+  = pprTrace "match_co: needs more cases" (ppr _co1 $$ ppr _co2) Nothing
+#else
+  = Nothing
+#endif
 
 match_cos :: RuleMatchEnv
          -> RuleSubst

ghc/InteractiveUI.hs

@@ -1225,6 +1225,9 @@ editFile str =
      when (null cmd)
        $ throwGhcException (CmdLineError "editor not set, use :set editor")
      lineOpt <- liftIO $ do
+         let sameFile p1 p2 = liftA2 (==) (canonicalizePath p1) (canonicalizePath p2)
+              `catchIO` (\_ -> return False)
+
          curFileErrs <- filterM (\(f, _) -> unpackFS f `sameFile` file) errs
          return $ case curFileErrs of
              (_, line):_ -> " +" ++ show line
@@ -3191,12 +3194,6 @@ expandPathIO p =
    other ->
         return other
 
-sameFile :: FilePath -> FilePath -> IO Bool
-sameFile path1 path2 = do
-    absPath1 <- canonicalizePath path1
-    absPath2 <- canonicalizePath path2
-    return $ absPath1 == absPath2
-
 wantInterpretedModule :: GHC.GhcMonad m => String -> m Module
 wantInterpretedModule str = wantInterpretedModuleName (GHC.mkModuleName str)
 

includes/stg/SMP.h

@@ -158,13 +158,11 @@ xchg(StgPtr p, StgWord w)
                           : "memory"
                           );
 #elif aarch64_HOST_ARCH
-    // Don't think we actually use tmp here, but leaving
-    // it for consistent numbering
     StgWord tmp; 
     __asm__ __volatile__ (
                           "1:    ldaxr  %0, [%3]\n"
-                          "      stlxr  %w0, %2, [%3]\n"
-                          "      cbnz   %w0, 1b\n"
+                          "      stlxr  %w1, %2, [%3]\n"
+                          "      cbnz   %w1, 1b\n"
                           "      dmb sy\n"
                           : "=&r" (result), "=&r" (tmp)
                           : "r" (w), "r" (p)

libraries/base/GHC/Event/Internal.hs

@@ -83,10 +83,12 @@ evtConcat :: [Event] -> Event
 evtConcat = foldl' evtCombine evtNothing
 {-# INLINE evtConcat #-}
 
--- | The lifetime of a registration.
+-- | The lifetime of an event registration.
 --
 -- @since 4.8.1.0
-data Lifetime = OneShot | MultiShot
+data Lifetime = OneShot   -- ^ the registration will be active for only one
+                          -- event
+              | MultiShot -- ^ the registration will trigger multiple times
               deriving (Show, Eq)
 
 -- | The longer of two lifetimes.
@@ -95,6 +97,7 @@ elSupremum OneShot OneShot = OneShot
 elSupremum _       _       = MultiShot
 {-# INLINE elSupremum #-}
 
+-- | @mappend@ == @elSupremum@
 instance Monoid Lifetime where
     mempty = OneShot
     mappend = elSupremum

libraries/base/GHC/Event/Manager.hs

@@ -456,38 +456,54 @@ onFdEvent mgr fd evs
 
   | otherwise = do
     fdds <- withMVar (callbackTableVar mgr fd) $ \tbl ->
-        IT.delete (fromIntegral fd) tbl >>= maybe (return []) selectCallbacks
+        IT.delete (fromIntegral fd) tbl >>= maybe (return []) (selectCallbacks tbl)
     forM_ fdds $ \(FdData reg _ cb) -> cb reg evs
   where
     -- | Here we look through the list of registrations for the fd of interest
-    -- and sort out which match the events that were triggered. We re-arm
-    -- the fd as appropriate and return this subset.
-    selectCallbacks :: [FdData] -> IO [FdData]
-    selectCallbacks fdds = do
-        let matches :: FdData -> Bool
+    -- and sort out which match the events that were triggered. We,
+    --
+    --   1. re-arm the fd as appropriate
+    --   2. reinsert registrations that weren't triggered and multishot
+    --      registrations
+    --   3. return a list containing the callbacks that should be invoked.
+    selectCallbacks :: IntTable [FdData] -> [FdData] -> IO [FdData]
+    selectCallbacks tbl fdds = do
+        let -- figure out which registrations have been triggered
+            matches :: FdData -> Bool
             matches fd' = evs `I.eventIs` I.elEvent (fdEvents fd')
-            (triggered, saved) = partition matches fdds
+            (triggered, notTriggered) = partition matches fdds
+
+            -- sort out which registrations we need to retain
+            isMultishot :: FdData -> Bool
+            isMultishot fd' = I.elLifetime (fdEvents fd') == MultiShot
+            saved = notTriggered ++ filter isMultishot triggered
+
             savedEls = eventsOf saved
             allEls = eventsOf fdds
 
+        -- Reinsert multishot registrations.
+        -- We deleted the table entry for this fd above so we there isn't a preexisting entry
+        _ <- IT.insertWith (\_ _ -> saved) (fromIntegral fd) saved tbl
+
         case I.elLifetime allEls of
           -- we previously armed the fd for multiple shots, no need to rearm
           MultiShot | allEls == savedEls ->
             return ()
 
           -- either we previously registered for one shot or the
           -- events of interest have changed, we must re-arm
-          _ -> do
+          _ ->
             case I.elLifetime savedEls of
               OneShot | haveOneShot ->
-                -- if there are no saved events there is no need to re-arm
-                unless (OneShot == I.elLifetime (eventsOf triggered)
-                        && mempty == savedEls) $
+                -- if there are no saved events and we registered with one-shot
+                -- semantics then there is no need to re-arm
+                unless (OneShot == I.elLifetime allEls
+                        && mempty == I.elEvent savedEls) $ do
                   void $ I.modifyFdOnce (emBackend mgr) fd (I.elEvent savedEls)
               _ ->
+                -- we need to re-arm with multi-shot semantics
                 void $ I.modifyFd (emBackend mgr) fd
                                   (I.elEvent allEls) (I.elEvent savedEls)
-            return ()
 
         return triggered
 

testsuite/tests/ghci/prog013/prog013.script

@@ -6,3 +6,7 @@
 :e ./Bad.hs
 :l Good.hs
 :e
++
+:e foo
+:l Bad.hs
+:e bar

testsuite/tests/ghci/prog013/prog013.stderr

@@ -1,9 +1,17 @@
 
-Bad.hs:3:8:
+Bad.hs:3:8: error:
     lexical error in string/character literal at character '\n'
 
-Bad.hs:3:8:
+Bad.hs:3:8: error:
     lexical error in string/character literal at character '\n'
 
-Bad.hs:3:8:
+Bad.hs:3:8: error:
+    lexical error in string/character literal at character '\n'
+
+<interactive>:10:1: error: parse error on input ‘+’
+
+Bad.hs:3:8: error:
+    lexical error in string/character literal at character '\n'
+
+Bad.hs:3:8: error:
     lexical error in string/character literal at character '\n'

testsuite/tests/ghci/prog013/prog013.stdout

@@ -2,3 +2,5 @@ Good.hs
 Bad.hs +3
 ./Bad.hs +3
 Good.hs
+foo
+bar