[commit: ghc] ghc-8.6: base: Mention openFile throwing does-not-exist-errors on FIFOs (64a5044)

[git at git.haskell.org]

Repository : ssh://git@git.haskell.org/ghc

On branch  : ghc-8.6
Link       : http://ghc.haskell.org/trac/ghc/changeset/64a5044543bdcd7983787b215a44bdfb70c9c40b/ghc

>---------------------------------------------------------------

commit 64a5044543bdcd7983787b215a44bdfb70c9c40b
Author: Ben Gamari <bgamari.foss at gmail.com>
Date:   Thu Nov 22 11:33:39 2018 -0500

    base: Mention openFile throwing does-not-exist-errors on FIFOs
    
    As discussed in #15715, the POSIX specification specifies that
    attempting to open a FIFO in write-only mode when the FIFO has no
    readers will fail with -ENOENT.
    
    [skip ci]
    
    Test Plan: Read it
    
    Reviewers: hvr
    
    Subscribers: rwbarton, carter
    
    GHC Trac Issues: #15715
    
    Differential Revision: https://phabricator.haskell.org/D5295
    
    (cherry picked from commit 4ba3fa31ddfa12b428bd67216a2d4118dc9e8311)


>---------------------------------------------------------------

64a5044543bdcd7983787b215a44bdfb70c9c40b
 libraries/base/GHC/IO/Handle/FD.hs | 6 ++++--
 1 file changed, 4 insertions(+), 2 deletions(-)

diff --git a/libraries/base/GHC/IO/Handle/FD.hs b/libraries/base/GHC/IO/Handle/FD.hs
index 786fccc..f7f8d04 100644
--- a/libraries/base/GHC/IO/Handle/FD.hs
+++ b/libraries/base/GHC/IO/Handle/FD.hs
@@ -130,7 +130,9 @@ addFilePathToIOError fun fp ioe
 --
 --  * 'isAlreadyInUseError' if the file is already open and cannot be reopened;
 --
---  * 'isDoesNotExistError' if the file does not exist; or
+--  * 'isDoesNotExistError' if the file does not exist or
+--    (on POSIX systems) is a FIFO without a reader and 'WriteMode' was
+--    requested; or
 --
 --  * 'isPermissionError' if the user does not have permission to open the file.
 --
@@ -161,7 +163,7 @@ openFileBlocking fp im =
 -- this is undesirable; also, as usual under Microsoft operating systems,
 -- text mode treats control-Z as EOF.  Binary mode turns off all special
 -- treatment of end-of-line and end-of-file characters.
--- (See also 'hSetBinaryMode'.)
+-- (See also 'System.IO.hSetBinaryMode'.)
 
 openBinaryFile :: FilePath -> IOMode -> IO Handle
 openBinaryFile fp m =