From 13ca58083dafe75ca6deb491bc38fe3479fe51aa Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Linus=20F=C3=A4rnstrand?= <faern@faern.net>
Date: Thu, 25 Mar 2021 08:50:10 +0100
Subject: [PATCH 1/2] Implement Into<!> for Infallible

---
 library/core/src/convert/mod.rs | 7 +++++++
 1 file changed, 7 insertions(+)

diff --git a/library/core/src/convert/mod.rs b/library/core/src/convert/mod.rs
index 65af8508a6839..1eaf5cf07d835 100644
--- a/library/core/src/convert/mod.rs
+++ b/library/core/src/convert/mod.rs
@@ -728,6 +728,13 @@ impl From<!> for Infallible {
     }
 }
 
+#[stable(feature = "convert_into_infallible", since = "1.53.0")]
+impl Into<!> for Infallible {
+    fn into(self) -> ! {
+        match self {}
+    }
+}
+
 #[stable(feature = "convert_infallible_hash", since = "1.44.0")]
 impl Hash for Infallible {
     fn hash<H: Hasher>(&self, _: &mut H) {

From 0a8fa2ab6c271fca754abb8de2187eae1dc03040 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Linus=20F=C3=A4rnstrand?= <faern@faern.net>
Date: Thu, 25 Mar 2021 21:17:38 +0100
Subject: [PATCH 2/2] Add tests

---
 library/core/tests/result.rs | 9 +++++++++
 1 file changed, 9 insertions(+)

diff --git a/library/core/tests/result.rs b/library/core/tests/result.rs
index c461ab380ad3d..f66ea26b62e01 100644
--- a/library/core/tests/result.rs
+++ b/library/core/tests/result.rs
@@ -1,3 +1,4 @@
+use core::convert::Infallible;
 use core::ops::DerefMut;
 use core::option::*;
 
@@ -208,8 +209,12 @@ pub fn test_into_ok() {
     fn infallible_op() -> Result<isize, !> {
         Ok(666)
     }
+    fn infallible_op_enum() -> Result<isize, Infallible> {
+        Ok(666)
+    }
 
     assert_eq!(infallible_op().into_ok(), 666);
+    assert_eq!(infallible_op_enum().into_ok(), 666);
 
     enum MyNeverToken {}
     impl From<MyNeverToken> for ! {
@@ -230,8 +235,12 @@ pub fn test_into_err() {
     fn until_error_op() -> Result<!, isize> {
         Err(666)
     }
+    fn until_error_op_enum() -> Result<Infallible, isize> {
+        Err(666)
+    }
 
     assert_eq!(until_error_op().into_err(), 666);
+    assert_eq!(until_error_op_enum().into_err(), 666);
 
     enum MyNeverToken {}
     impl From<MyNeverToken> for ! {