From fd207e67d5923f4cec2a96c4b095a1e3bbdac5a7 Mon Sep 17 00:00:00 2001
From: David Tolnay <dtolnay@gmail.com>
Date: Thu, 28 Sep 2023 10:07:40 -0700
Subject: [PATCH] Const stabilize mem::discriminant

---
 library/core/src/intrinsics.rs        | 2 +-
 library/core/src/lib.rs               | 1 -
 library/core/src/mem/mod.rs           | 2 +-
 tests/ui/consts/const-eval/ub-enum.rs | 2 +-
 tests/ui/consts/const_discriminant.rs | 1 -
 5 files changed, 3 insertions(+), 5 deletions(-)

diff --git a/library/core/src/intrinsics.rs b/library/core/src/intrinsics.rs
index 4c76662ac0975..e5362fd5aeaaa 100644
--- a/library/core/src/intrinsics.rs
+++ b/library/core/src/intrinsics.rs
@@ -2277,7 +2277,7 @@ extern "rust-intrinsic" {
     /// any safety invariants.
     ///
     /// The stabilized version of this intrinsic is [`core::mem::discriminant`].
-    #[rustc_const_unstable(feature = "const_discriminant", issue = "69821")]
+    #[rustc_const_stable(feature = "const_discriminant", since = "CURRENT_RUSTC_VERSION")]
     #[rustc_safe_intrinsic]
     #[rustc_nounwind]
     pub fn discriminant_value<T>(v: &T) -> <T as DiscriminantKind>::Discriminant;
diff --git a/library/core/src/lib.rs b/library/core/src/lib.rs
index 8b04bafcda54a..1bcde4242cde8 100644
--- a/library/core/src/lib.rs
+++ b/library/core/src/lib.rs
@@ -126,7 +126,6 @@
 #![feature(const_caller_location)]
 #![feature(const_cell_into_inner)]
 #![feature(const_char_from_u32_unchecked)]
-#![feature(const_discriminant)]
 #![feature(const_eval_select)]
 #![feature(const_exact_div)]
 #![feature(const_float_bits_conv)]
diff --git a/library/core/src/mem/mod.rs b/library/core/src/mem/mod.rs
index d7abc9a0e23aa..ae88231ae6e46 100644
--- a/library/core/src/mem/mod.rs
+++ b/library/core/src/mem/mod.rs
@@ -1202,7 +1202,7 @@ impl<T> fmt::Debug for Discriminant<T> {
 /// // assert_eq!(0, unsafe { std::mem::transmute::<_, u8>(std::mem::discriminant(&unit_like)) });
 /// ```
 #[stable(feature = "discriminant_value", since = "1.21.0")]
-#[rustc_const_unstable(feature = "const_discriminant", issue = "69821")]
+#[rustc_const_stable(feature = "const_discriminant", since = "CURRENT_RUSTC_VERSION")]
 #[cfg_attr(not(test), rustc_diagnostic_item = "mem_discriminant")]
 #[cfg_attr(miri, track_caller)] // even without panics, this helps for Miri backtraces
 pub const fn discriminant<T>(v: &T) -> Discriminant<T> {
diff --git a/tests/ui/consts/const-eval/ub-enum.rs b/tests/ui/consts/const-eval/ub-enum.rs
index 078283fbd1f7d..72a0c9efed2cc 100644
--- a/tests/ui/consts/const-eval/ub-enum.rs
+++ b/tests/ui/consts/const-eval/ub-enum.rs
@@ -2,7 +2,7 @@
 // Strip out raw byte dumps to make comparison platform-independent:
 // normalize-stderr-test "(the raw bytes of the constant) \(size: [0-9]*, align: [0-9]*\)" -> "$1 (size: $$SIZE, align: $$ALIGN)"
 // normalize-stderr-test "([0-9a-f][0-9a-f] |╾─*a(lloc)?[0-9]+(\+[a-z0-9]+)?─*╼ )+ *│.*" -> "HEX_DUMP"
-#![feature(never_type, const_discriminant)]
+#![feature(never_type)]
 #![allow(invalid_value)]
 
 use std::mem;
diff --git a/tests/ui/consts/const_discriminant.rs b/tests/ui/consts/const_discriminant.rs
index b1180faa69776..80deb0f784d26 100644
--- a/tests/ui/consts/const_discriminant.rs
+++ b/tests/ui/consts/const_discriminant.rs
@@ -1,5 +1,4 @@
 // run-pass
-#![feature(const_discriminant)]
 #![allow(dead_code)]
 
 use std::mem::{discriminant, Discriminant};