Auto merge of #67136 - oli-obk:const_stability, r=Centril

Require stable/unstable annotations for the constness of all stable fns with a const modifier

r? @RalfJung @Centril

Every `#[stable]` const fn now needs either a `#[rustc_const_unstable]` attribute or a `#[rustc_const_stable]` attribute. You can't silently stabilize the constness of a function anymore.

1 files changed, 1 insertions, 0 deletions

diff --git a/src/libstd/sync/once.rs b/src/libstd/sync/once.rs
index e8e395247f9..d8df09071cd 100644
--- a/src/libstd/sync/once.rs
+++ b/src/libstd/sync/once.rs
@@ -188,6 +188,7 @@ struct WaiterQueue<'a> {
 impl Once {
     /// Creates a new `Once` value.
     #[stable(feature = "once_new", since = "1.2.0")]
+    #[cfg_attr(not(bootstrap), rustc_const_stable(feature = "const_once_new", since = "1.32.0"))]
     pub const fn new() -> Once {
         Once { state_and_queue: AtomicUsize::new(INCOMPLETE), _marker: marker::PhantomData }
     }