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, 4 insertions, 0 deletions

diff --git a/src/liballoc/string.rs b/src/liballoc/string.rs
index f7dff4c21f7..bf9bbba4753 100644
--- a/src/liballoc/string.rs
+++ b/src/liballoc/string.rs
@@ -367,6 +367,10 @@ impl String {
     /// let s = String::new();
     /// ```
     #[inline]
+    #[cfg_attr(
+        not(bootstrap),
+        rustc_const_stable(feature = "const_string_new", since = "1.32.0"),
+    )]
     #[stable(feature = "rust1", since = "1.0.0")]
     pub const fn new() -> String {
         String { vec: Vec::new() }