From 16529d723a1d66fbd926d7a8e78fb0448622a316 Mon Sep 17 00:00:00 2001 From: "Tim (Theemathas Chirananthavat)" Date: Sun, 6 Sep 2026 21:01:08 +0700 Subject: [PATCH 1/2] Make `VaArgSafe` dyn-incompatible This is done just in case we want to later do stuff like adding a `Sized` supertrait. See discussion at https://rust-lang.zulipchat.com/#narrow/channel/219381-t-libs/topic/Should.20.60VaArgSafe.60.20require.20.60Sized.60.3F/with/622074620 --- library/core/src/ffi/va_list.rs | 1 + 1 file changed, 1 insertion(+) diff --git a/library/core/src/ffi/va_list.rs b/library/core/src/ffi/va_list.rs index 63942003c568b..f050a18b842ee 100644 --- a/library/core/src/ffi/va_list.rs +++ b/library/core/src/ffi/va_list.rs @@ -309,6 +309,7 @@ const impl<'f> Drop for VaList<'f> { // meantime. #[lang = "va_arg_safe"] #[stable(feature = "c_variadic", since = "1.99.0")] +#[rustc_dyn_incompatible_trait] pub impl(self) unsafe trait VaArgSafe {} crate::cfg_select! { From 246105d1a14a4dfa124d503b1b9fd929606014e6 Mon Sep 17 00:00:00 2001 From: "Tim (Theemathas) Chirananthavat" Date: Mon, 7 Sep 2026 01:17:13 +0700 Subject: [PATCH 2/2] Acknowledge "breaking" change This PR does a "breaking" change on API that's stabilized in 1.99.0 beta, but has not reached stable yet, so we can make this change. H th is PR will need a beta backport. --- src/bootstrap/stdlib-semver-check-stamp | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/src/bootstrap/stdlib-semver-check-stamp b/src/bootstrap/stdlib-semver-check-stamp index 3462b7f3cd9eb..a7221ad6185e3 100644 --- a/src/bootstrap/stdlib-semver-check-stamp +++ b/src/bootstrap/stdlib-semver-check-stamp @@ -2,4 +2,4 @@ Change this file to explicitly acknowledge making a breaking change to the Rust If this file is modified in the same PR as the breaking change, then CI will not fail due to the breaking change being detected by cargo-semver-checks. -Last change is for: https://github.com/rust-lang/rust/pull/155499 +Last change is for: https://github.com/rust-lang/rust/pull/162374