From 046ca13356813af0817a7b3744315d012832fe2e Mon Sep 17 00:00:00 2001
From: Andrew Martin <andrew.thaddeus@gmail.com>
Date: Mon, 19 Aug 2019 11:12:48 -0400
Subject: Add predicates for testing if IOError is ResourceVanished.

This adds isResourceVanished, resourceVanishedErrorType, and
isResourceVanishedErrorType to System.IO.Error, resolving #14730.
---
 libraries/base/System/IO/Error.hs | 26 ++++++++++++++++++++++++++
 libraries/base/changelog.md       |  3 +++
 2 files changed, 29 insertions(+)

diff --git a/libraries/base/System/IO/Error.hs b/libraries/base/System/IO/Error.hs
index 2de6629a89..2585181df8 100644
--- a/libraries/base/System/IO/Error.hs
+++ b/libraries/base/System/IO/Error.hs
@@ -35,6 +35,7 @@ module System.IO.Error (
     isIllegalOperation,
     isPermissionError,
     isUserError,
+    isResourceVanishedError,
 
     -- ** Attributes of I\/O errors
     ioeGetErrorType,
@@ -60,6 +61,7 @@ module System.IO.Error (
     illegalOperationErrorType,
     permissionErrorType,
     userErrorType,
+    resourceVanishedErrorType,
 
     -- ** 'IOErrorType' predicates
     isAlreadyExistsErrorType,
@@ -70,6 +72,7 @@ module System.IO.Error (
     isIllegalOperationErrorType,
     isPermissionErrorType,
     isUserErrorType,
+    isResourceVanishedErrorType,
 
     -- * Throwing and catching I\/O errors
 
@@ -170,6 +173,13 @@ isPermissionError    = isPermissionErrorType       . ioeGetErrorType
 isUserError         :: IOError -> Bool
 isUserError          = isUserErrorType             . ioeGetErrorType
 
+-- | An error indicating that the operation failed because the
+-- resource vanished. See 'resourceVanishedErrorType'.
+--
+-- @since 0.4.14.0
+isResourceVanishedError :: IOError -> Bool
+isResourceVanishedError = isResourceVanishedErrorType . ioeGetErrorType
+
 -- -----------------------------------------------------------------------------
 -- IOErrorTypes
 
@@ -210,6 +220,14 @@ permissionErrorType       = PermissionDenied
 userErrorType            :: IOErrorType
 userErrorType             = UserError
 
+-- | I\/O error where the operation failed because the resource vanished.
+-- This happens when, for example, attempting to write to a closed
+-- socket or attempting to write to a named pipe that was deleted.
+--
+-- @since 0.4.14.0
+resourceVanishedErrorType :: IOErrorType
+resourceVanishedErrorType = ResourceVanished
+
 -- -----------------------------------------------------------------------------
 -- IOErrorType predicates
 
@@ -258,6 +276,14 @@ isUserErrorType :: IOErrorType -> Bool
 isUserErrorType UserError = True
 isUserErrorType _ = False
 
+-- | I\/O error where the operation failed because the resource vanished.
+-- See 'resourceVanishedErrorType'.
+--
+-- @since 0.4.14.0
+isResourceVanishedErrorType :: IOErrorType -> Bool
+isResourceVanishedErrorType ResourceVanished = True
+isResourceVanishedErrorType _ = False
+
 -- -----------------------------------------------------------------------------
 -- Miscellaneous
 
diff --git a/libraries/base/changelog.md b/libraries/base/changelog.md
index e404442801..0f2c72a9ac 100644
--- a/libraries/base/changelog.md
+++ b/libraries/base/changelog.md
@@ -30,6 +30,9 @@
 
   * `openTempFile` is now fully atomic and thread-safe on Windows.
 
+  * Add `isResourceVanishedError`, `resourceVanishedErrorType`, and
+    `isResourceVanishedErrorType` to `System.IO.Error`.
+
 ## 4.13.0.0 *TBA*
   * Bundled with GHC *TBA*
 
-- 
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