From 03e0c8edb2114aaf92fb8d93a18dfb0028690765 Mon Sep 17 00:00:00 2001
From: Ralf Jung <post@ralfj.de>
Date: Sat, 7 Sep 2024 22:19:30 +0200
Subject: [PATCH 1/3] make Result::copied unstably const
---
library/core/src/result.rs | 10 ++++++++--
1 file changed, 8 insertions(+), 2 deletions(-)
diff --git a/library/core/src/result.rs b/library/core/src/result.rs
index 73b11f803d929..a7fd95e007982 100644
--- a/library/core/src/result.rs
+++ b/library/core/src/result.rs
@@ -1535,11 +1535,17 @@ impl<T, E> Result<&T, E> {
/// ```
#[inline]
#[stable(feature = "result_copied", since = "1.59.0")]
- pub fn copied(self) -> Result<T, E>
+ #[rustc_const_unstable(feature = "const_result", issue = "82814")]
+ pub const fn copied(self) -> Result<T, E>
where
T: Copy,
{
- self.map(|&t| t)
+ // FIXME: this implementation, which sidesteps using `Result::map` since it's not const
+ // ready yet, should be reverted when possible to avoid code repetition
+ match self {
+ Ok(&v) => Ok(v),
+ Err(e) => Err(e),
+ }
}
/// Maps a `Result<&T, E>` to a `Result<T, E>` by cloning the contents of the
From 3de6838238dd72004acf0e6b3f158837952c1dc3 Mon Sep 17 00:00:00 2001
From: Ralf Jung <post@ralfj.de>
Date: Sun, 8 Sep 2024 08:30:28 +0200
Subject: [PATCH 2/3] add some FIXME(const-hack)
---
library/core/src/option.rs | 2 +-
library/core/src/result.rs | 2 +-
2 files changed, 2 insertions(+), 2 deletions(-)
diff --git a/library/core/src/option.rs b/library/core/src/option.rs
index 50cb22b7eb3f5..b62eec1897b09 100644
--- a/library/core/src/option.rs
+++ b/library/core/src/option.rs
@@ -1894,7 +1894,7 @@ impl<T> Option<&T> {
where
T: Copy,
{
- // FIXME: this implementation, which sidesteps using `Option::map` since it's not const
+ // FIXME(const-hack): this implementation, which sidesteps using `Option::map` since it's not const
// ready yet, should be reverted when possible to avoid code repetition
match self {
Some(&v) => Some(v),
diff --git a/library/core/src/result.rs b/library/core/src/result.rs
index a7fd95e007982..5b6a81c8dae91 100644
--- a/library/core/src/result.rs
+++ b/library/core/src/result.rs
@@ -1540,7 +1540,7 @@ impl<T, E> Result<&T, E> {
where
T: Copy,
{
- // FIXME: this implementation, which sidesteps using `Result::map` since it's not const
+ // FIXME(const-hack): this implementation, which sidesteps using `Result::map` since it's not const
// ready yet, should be reverted when possible to avoid code repetition
match self {
Ok(&v) => Ok(v),
From f7b4f4a73bcaa2987fddfa86c240a497780c88c8 Mon Sep 17 00:00:00 2001
From: Ralf Jung <post@ralfj.de>
Date: Sun, 8 Sep 2024 09:24:06 +0200
Subject: [PATCH 3/3] Option, Result: put the &mut variants of 'copied' under
the same feature as the '&' variants
---
library/core/src/option.rs | 2 +-
library/core/src/result.rs | 10 ++++++++--
2 files changed, 9 insertions(+), 3 deletions(-)
diff --git a/library/core/src/option.rs b/library/core/src/option.rs
index b62eec1897b09..80598b8852955 100644
--- a/library/core/src/option.rs
+++ b/library/core/src/option.rs
@@ -1942,7 +1942,7 @@ impl<T> Option<&mut T> {
/// ```
#[must_use = "`self` will be dropped if the result is not used"]
#[stable(feature = "copied", since = "1.35.0")]
- #[rustc_const_unstable(feature = "const_option_ext", issue = "91930")]
+ #[rustc_const_unstable(feature = "const_option", issue = "67441")]
pub const fn copied(self) -> Option<T>
where
T: Copy,
diff --git a/library/core/src/result.rs b/library/core/src/result.rs
index 5b6a81c8dae91..02f6f783b512c 100644
--- a/library/core/src/result.rs
+++ b/library/core/src/result.rs
@@ -1585,11 +1585,17 @@ impl<T, E> Result<&mut T, E> {
/// ```
#[inline]
#[stable(feature = "result_copied", since = "1.59.0")]
- pub fn copied(self) -> Result<T, E>
+ #[rustc_const_unstable(feature = "const_result", issue = "82814")]
+ pub const fn copied(self) -> Result<T, E>
where
T: Copy,
{
- self.map(|&mut t| t)
+ // FIXME(const-hack): this implementation, which sidesteps using `Result::map` since it's not const
+ // ready yet, should be reverted when possible to avoid code repetition
+ match self {
+ Ok(&mut v) => Ok(v),
+ Err(e) => Err(e),
+ }
}
/// Maps a `Result<&mut T, E>` to a `Result<T, E>` by cloning the contents of the