From 7430b22b5f83ac20cf51a76c1e755aa6e14557a0 Mon Sep 17 00:00:00 2001
From: woppopo <woppopo@protonmail.com>
Date: Tue, 26 Oct 2021 00:41:39 +0900
Subject: [PATCH] Make `Option::expect` const

---
 library/core/src/option.rs | 5 +++--
 1 file changed, 3 insertions(+), 2 deletions(-)

diff --git a/library/core/src/option.rs b/library/core/src/option.rs
index f4ce7d1dfb334..7dfbbe9cd950e 100644
--- a/library/core/src/option.rs
+++ b/library/core/src/option.rs
@@ -703,7 +703,8 @@ impl<T> Option<T> {
     #[inline]
     #[track_caller]
     #[stable(feature = "rust1", since = "1.0.0")]
-    pub fn expect(self, msg: &str) -> T {
+    #[rustc_const_unstable(feature = "const_option", issue = "67441")]
+    pub const fn expect(self, msg: &str) -> T {
         match self {
             Some(val) => val,
             None => expect_failed(msg),
@@ -1634,7 +1635,7 @@ impl<T, E> Option<Result<T, E>> {
 #[inline(never)]
 #[cold]
 #[track_caller]
-fn expect_failed(msg: &str) -> ! {
+const fn expect_failed(msg: &str) -> ! {
     panic!("{}", msg)
 }