From a191d1c271b1c95811e97dbbc0d074c41a0d75a4 Mon Sep 17 00:00:00 2001
From: Nikolai Vazquez <hello@nikolaivazquez.com>
Date: Thu, 28 Apr 2022 02:57:19 -0400
Subject: [PATCH 1/3] Implement `From<TryReserveError>` for `io::Error`

The `try_reserve` methods may be called when allocating for I/O.
---
 library/std/src/io/error.rs | 16 ++++++++++++++++
 1 file changed, 16 insertions(+)

diff --git a/library/std/src/io/error.rs b/library/std/src/io/error.rs
index 4a50e647c640e..27a8ca7a2fd7f 100644
--- a/library/std/src/io/error.rs
+++ b/library/std/src/io/error.rs
@@ -11,6 +11,7 @@ mod repr_unpacked;
 #[cfg(not(target_pointer_width = "64"))]
 use repr_unpacked::Repr;
 
+use crate::collections::{TryReserveError, TryReserveErrorKind};
 use crate::convert::From;
 use crate::error;
 use crate::fmt;
@@ -465,6 +466,21 @@ impl From<ErrorKind> for Error {
     }
 }
 
+#[stable(feature = "io_error_from_try_reserve", since = "1.62.0")]
+impl From<TryReserveError> for Error {
+    #[inline]
+    fn from(error: TryReserveError) -> Error {
+        match error.kind() {
+            TryReserveErrorKind::CapacityOverflow => {
+                ErrorKind::InvalidInput.into()
+            }
+            TryReserveErrorKind::AllocError { .. } => {
+                ErrorKind::OutOfMemory.into()
+            }
+        }
+    }
+}
+
 impl Error {
     /// Creates a new I/O error from a known kind of error as well as an
     /// arbitrary error payload.

From ecb94ba6ddce5ef3e23cfa450e120ecaca6d17ca Mon Sep 17 00:00:00 2001
From: Nikolai Vazquez <hello@nikolaivazquez.com>
Date: Thu, 28 Apr 2022 03:06:21 -0400
Subject: [PATCH 2/3] Add error messages

---
 library/std/src/io/error.rs | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/library/std/src/io/error.rs b/library/std/src/io/error.rs
index 27a8ca7a2fd7f..714e14415a2cf 100644
--- a/library/std/src/io/error.rs
+++ b/library/std/src/io/error.rs
@@ -472,10 +472,10 @@ impl From<TryReserveError> for Error {
     fn from(error: TryReserveError) -> Error {
         match error.kind() {
             TryReserveErrorKind::CapacityOverflow => {
-                ErrorKind::InvalidInput.into()
+                const_io_error!(ErrorKind::InvalidInput, "collection capacity overflowed")
             }
             TryReserveErrorKind::AllocError { .. } => {
-                ErrorKind::OutOfMemory.into()
+                const_io_error!(ErrorKind::OutOfMemory, "collection cannot allocate memory")
             }
         }
     }

From c35eb0a372d816a4bb3b49a4eb795fd6fbfbdb9e Mon Sep 17 00:00:00 2001
From: Nikolai Vazquez <hello@nikolaivazquez.com>
Date: Thu, 28 Apr 2022 03:13:12 -0400
Subject: [PATCH 3/3] Switch to `io::Error::new`

---
 library/std/src/io/error.rs | 14 ++++++--------
 1 file changed, 6 insertions(+), 8 deletions(-)

diff --git a/library/std/src/io/error.rs b/library/std/src/io/error.rs
index 714e14415a2cf..049fe4e433833 100644
--- a/library/std/src/io/error.rs
+++ b/library/std/src/io/error.rs
@@ -470,14 +470,12 @@ impl From<ErrorKind> for Error {
 impl From<TryReserveError> for Error {
     #[inline]
     fn from(error: TryReserveError) -> Error {
-        match error.kind() {
-            TryReserveErrorKind::CapacityOverflow => {
-                const_io_error!(ErrorKind::InvalidInput, "collection capacity overflowed")
-            }
-            TryReserveErrorKind::AllocError { .. } => {
-                const_io_error!(ErrorKind::OutOfMemory, "collection cannot allocate memory")
-            }
-        }
+        let kind = match error.kind() {
+            TryReserveErrorKind::CapacityOverflow => ErrorKind::InvalidInput,
+            TryReserveErrorKind::AllocError { .. } => ErrorKind::OutOfMemory,
+        };
+
+        Error::new(kind, error)
     }
 }