From db109c662e4bc4a8d81aaa69e6bd37c43d191259 Mon Sep 17 00:00:00 2001
From: CDirkx <christiaan@dirkx.com>
Date: Mon, 31 Aug 2020 02:11:48 +0200
Subject: [PATCH 1/2] Stabilize some Option methods as const

Stabilize the following methods of `Option` as const:
 - `is_some`
 - `is_none`
 - `as_ref`

Possible because of stabilization of #49146 (Allow if and match in constants).
---
 library/core/src/option.rs         | 6 +++---
 src/test/ui/consts/const-option.rs | 2 --
 2 files changed, 3 insertions(+), 5 deletions(-)

diff --git a/library/core/src/option.rs b/library/core/src/option.rs
index dd7556758be7d..fa0f917c79dca 100644
--- a/library/core/src/option.rs
+++ b/library/core/src/option.rs
@@ -175,7 +175,7 @@ impl<T> Option<T> {
     /// ```
     #[must_use = "if you intended to assert that this has a value, consider `.unwrap()` instead"]
     #[inline]
-    #[rustc_const_unstable(feature = "const_option", issue = "67441")]
+    #[rustc_const_stable(feature = "const_option", since = "1.48.0")]
     #[stable(feature = "rust1", since = "1.0.0")]
     pub const fn is_some(&self) -> bool {
         matches!(*self, Some(_))
@@ -195,7 +195,7 @@ impl<T> Option<T> {
     #[must_use = "if you intended to assert that this doesn't have a value, consider \
                   `.and_then(|| panic!(\"`Option` had a value when expected `None`\"))` instead"]
     #[inline]
-    #[rustc_const_unstable(feature = "const_option", issue = "67441")]
+    #[rustc_const_stable(feature = "const_option", since = "1.48.0")]
     #[stable(feature = "rust1", since = "1.0.0")]
     pub const fn is_none(&self) -> bool {
         !self.is_some()
@@ -254,7 +254,7 @@ impl<T> Option<T> {
     /// println!("still can print text: {:?}", text);
     /// ```
     #[inline]
-    #[rustc_const_unstable(feature = "const_option", issue = "67441")]
+    #[rustc_const_stable(feature = "const_option", since = "1.48.0")]
     #[stable(feature = "rust1", since = "1.0.0")]
     pub const fn as_ref(&self) -> Option<&T> {
         match *self {
diff --git a/src/test/ui/consts/const-option.rs b/src/test/ui/consts/const-option.rs
index fbf20b9db6741..793f78c8d20fa 100644
--- a/src/test/ui/consts/const-option.rs
+++ b/src/test/ui/consts/const-option.rs
@@ -1,7 +1,5 @@
 // run-pass
 
-#![feature(const_option)]
-
 const X: Option<i32> = Some(32);
 const Y: Option<&i32> = X.as_ref();
 

From 04e4a391985994f7ccb579eae530b52d704eb887 Mon Sep 17 00:00:00 2001
From: Christiaan Dirkx <christiaan@dirkx.email>
Date: Fri, 4 Sep 2020 00:13:25 +0200
Subject: [PATCH 2/2] Move const tests for `Option` to `library\core`

Part of #76268
---
 library/core/tests/option.rs       | 16 ++++++++++++++++
 src/test/ui/consts/const-option.rs | 12 ------------
 2 files changed, 16 insertions(+), 12 deletions(-)
 delete mode 100644 src/test/ui/consts/const-option.rs

diff --git a/library/core/tests/option.rs b/library/core/tests/option.rs
index fa308160fc228..5049ba954c7a2 100644
--- a/library/core/tests/option.rs
+++ b/library/core/tests/option.rs
@@ -357,3 +357,19 @@ fn test_replace() {
     assert_eq!(x, Some(3));
     assert_eq!(old, None);
 }
+
+#[test]
+fn option_const() {
+    // test that the methods of `Option` are usable in a const context
+
+    const OPTION: Option<usize> = Some(32);
+
+    const REF: Option<&usize> = OPTION.as_ref();
+    assert_eq!(REF, Some(&32));
+
+    const IS_SOME: bool = OPTION.is_some();
+    assert!(IS_SOME);
+
+    const IS_NONE: bool = OPTION.is_none();
+    assert!(!IS_NONE);
+}
diff --git a/src/test/ui/consts/const-option.rs b/src/test/ui/consts/const-option.rs
deleted file mode 100644
index 793f78c8d20fa..0000000000000
--- a/src/test/ui/consts/const-option.rs
+++ /dev/null
@@ -1,12 +0,0 @@
-// run-pass
-
-const X: Option<i32> = Some(32);
-const Y: Option<&i32> = X.as_ref();
-
-const IS_SOME: bool = X.is_some();
-const IS_NONE: bool = Y.is_none();
-
-fn main() {
-    assert!(IS_SOME);
-    assert!(!IS_NONE)
-}