Claw back VaArgSafe

Author: maxdexh

library/core/src/ffi/va_list.rs

@@ -308,7 +308,7 @@ const impl<'f> Drop for VaList<'f> {
 // types with a non-scalar layout. Inline assembly can be used to accept unsupported types in the
 // meantime.
 #[lang = "va_arg_safe"]
-#[stable(feature = "c_variadic", since = "1.99.0")]
+#[unstable(feature = "c_variadic_va_arg_safe", issue = "44930")]
 #[rustc_dyn_incompatible_trait]
 pub impl(self) unsafe trait VaArgSafe {}
 
@@ -318,9 +318,9 @@ crate::cfg_select! {
         //
         // - i8 is implicitly promoted to c_int in C, and cannot implement `VaArgSafe`.
         // - u8 is implicitly promoted to c_uint in C, and cannot implement `VaArgSafe`.
-        #[stable(feature = "c_variadic", since = "1.99.0")]
+        #[unstable(feature = "c_variadic_va_arg_safe", issue = "44930")]
         unsafe impl VaArgSafe for i16 {}
-        #[stable(feature = "c_variadic", since = "1.99.0")]
+        #[unstable(feature = "c_variadic_va_arg_safe", issue = "44930")]
         unsafe impl VaArgSafe for u16 {}
     }
     _ => {
@@ -334,7 +334,7 @@ crate::cfg_select! {
 crate::cfg_select! {
     target_arch = "avr" => {
         // c_double is f32 on this target.
-        #[stable(feature = "c_variadic", since = "1.99.0")]
+        #[unstable(feature = "c_variadic_va_arg_safe", issue = "44930")]
         unsafe impl VaArgSafe for f32 {}
     }
     _ => {
@@ -344,18 +344,18 @@ crate::cfg_select! {
     }
 }
 
-#[stable(feature = "c_variadic", since = "1.99.0")]
+#[unstable(feature = "c_variadic_va_arg_safe", issue = "44930")]
 unsafe impl VaArgSafe for i32 {}
-#[stable(feature = "c_variadic", since = "1.99.0")]
+#[unstable(feature = "c_variadic_va_arg_safe", issue = "44930")]
 unsafe impl VaArgSafe for i64 {}
-#[stable(feature = "c_variadic", since = "1.99.0")]
+#[unstable(feature = "c_variadic_va_arg_safe", issue = "44930")]
 unsafe impl VaArgSafe for isize {}
 
-#[stable(feature = "c_variadic", since = "1.99.0")]
+#[unstable(feature = "c_variadic_va_arg_safe", issue = "44930")]
 unsafe impl VaArgSafe for u32 {}
-#[stable(feature = "c_variadic", since = "1.99.0")]
+#[unstable(feature = "c_variadic_va_arg_safe", issue = "44930")]
 unsafe impl VaArgSafe for u64 {}
-#[stable(feature = "c_variadic", since = "1.99.0")]
+#[unstable(feature = "c_variadic_va_arg_safe", issue = "44930")]
 unsafe impl VaArgSafe for usize {}
 
 // Implement `VaArgSafe` for 128-bit integers on targets where clang provides `__int128`.
@@ -413,12 +413,12 @@ cfg_select! {
     }
 }
 
-#[stable(feature = "c_variadic", since = "1.99.0")]
+#[unstable(feature = "c_variadic_va_arg_safe", issue = "44930")]
 unsafe impl VaArgSafe for f64 {}
 
-#[stable(feature = "c_variadic", since = "1.99.0")]
+#[unstable(feature = "c_variadic_va_arg_safe", issue = "44930")]
 unsafe impl<T> VaArgSafe for *mut T {}
-#[stable(feature = "c_variadic", since = "1.99.0")]
+#[unstable(feature = "c_variadic_va_arg_safe", issue = "44930")]
 unsafe impl<T> VaArgSafe for *const T {}
 
 // Check that relevant `core::ffi` types implement `VaArgSafe`.

library/std/src/ffi/mod.rs

@@ -164,10 +164,12 @@
 #[stable(feature = "c_str_module", since = "1.88.0")]
 pub mod c_str;
 
+#[unstable(feature = "c_variadic_va_arg_safe", issue = "44930")]
+pub use core::ffi::VaArgSafe;
+#[stable(feature = "c_variadic", since = "1.99.0")]
+pub use core::ffi::VaList;
 #[stable(feature = "core_c_void", since = "1.30.0")]
 pub use core::ffi::c_void;
-#[stable(feature = "c_variadic", since = "1.99.0")]
-pub use core::ffi::{VaArgSafe, VaList};
 #[stable(feature = "core_ffi_c", since = "1.64.0")]
 pub use core::ffi::{
     c_char, c_double, c_float, c_int, c_long, c_longlong, c_schar, c_short, c_uchar, c_uint,

tests/ui/c-variadic/roundtrip.rs

@@ -1,6 +1,12 @@
 //@ run-pass
 //@ ignore-backends: gcc
-#![feature(const_c_variadic, c_variadic_int128, const_destruct, const_raw_ptr_comparison)]
+#![feature(
+    const_c_variadic,
+    c_variadic_va_arg_safe,
+    c_variadic_int128,
+    const_destruct,
+    const_raw_ptr_comparison
+)]
 #![allow(unused_features)] // c_variadic_int128 is only used on 64-bit targets.
 
 use std::ffi::*;

tests/ui/consts/const-eval/c-variadic-fail.rs

@@ -4,6 +4,7 @@
 #![feature(const_trait_impl)]
 #![feature(const_destruct)]
 #![feature(const_clone)]
+#![feature(c_variadic_va_arg_safe)]
 
 use std::ffi::{VaList, c_char, c_void};
 use std::mem::MaybeUninit;