stabilize c_variadic_naked_functions

compiler/rustc_abi/src/extern_abi.rs

@@ -290,8 +290,8 @@ impl ExternAbi {
     }
 
     /// Returns whether the ABI supports C variadics. This only controls whether we allow *imports*
-    /// of such functions via `extern` blocks; there's a separate check during AST construction
-    /// guarding *definitions* of variadic functions.
+    /// of such functions via `extern` blocks and definition via naked functions; there's a
+    /// separate check during AST construction guarding *definitions* of variadic functions.
     #[cfg(feature = "nightly")]
     pub fn supports_c_variadic(self) -> CVariadicStatus {
         // * C and Cdecl obviously support varargs.

compiler/rustc_ast_passes/src/ast_validation.rs

@@ -957,29 +957,14 @@ impl<'a> AstValidator<'a> {
         dotdotdot_span: Span,
         sig: &FnSig,
     ) {
-        // For naked functions we accept any ABI that is accepted on c-variadic
-        // foreign functions, if the c_variadic_naked_functions feature is enabled.
         if attr::contains_name(attrs, sym::naked) {
             match abi.supports_c_variadic() {
-                CVariadicStatus::Stable if let ExternAbi::C { .. } = abi => {
-                    // With `c_variadic` naked c-variadic `extern "C"` functions are allowed.
-                }
                 CVariadicStatus::Stable => {
-                    // For e.g. aapcs or sysv64 `c_variadic_naked_functions` must also be enabled.
-                    if !self.features.enabled(sym::c_variadic_naked_functions) {
-                        let msg = format!("Naked c-variadic `extern {abi}` functions are unstable");
-                        feature_err(&self.sess, sym::c_variadic_naked_functions, sig.span, msg)
-                            .emit();
-                    }
+                    // For naked functions we accept any ABI that is accepted
+                    // on c-variadic foreign functions.
                 }
                 CVariadicStatus::Unstable { feature } => {
-                    // Some ABIs need additional features.
-                    if !self.features.enabled(sym::c_variadic_naked_functions) {
-                        let msg = format!("Naked c-variadic `extern {abi}` functions are unstable");
-                        feature_err(&self.sess, sym::c_variadic_naked_functions, sig.span, msg)
-                            .emit();
-                    }
-
+                    // Some ABIs need additional features to be enabled.
                     if !self.features.enabled(feature) {
                         let msg = format!(
                             "C-variadic functions with the {abi} calling convention are unstable"

compiler/rustc_feature/src/accepted.rs

@@ -96,6 +96,9 @@ declare_features! (
     (accepted, c_unwind, "1.81.0", Some(74990)),
     /// Allows using C-variadics.
     (accepted, c_variadic, "CURRENT_RUSTC_VERSION", Some(44930)),
+    /// Allows defining c-variadic naked functions with any extern ABI that is allowed
+    /// on c-variadic foreign functions.
+    (accepted, c_variadic_naked_functions, "CURRENT_RUSTC_VERSION", Some(148767)),
     /// Allows `#[cfg_attr(predicate, multiple, attributes, here)]`.
     (accepted, cfg_attr_multi, "1.33.0", Some(54881)),
     /// Allows the use of `#[cfg(<true/false>)]`.

compiler/rustc_feature/src/unstable.rs

@@ -427,9 +427,6 @@ declare_features! (
     /// Allows defining c-variadic functions on targets where this feature has not yet
     /// undergone sufficient testing for stabilization.
     (unstable, c_variadic_experimental_arch, "1.97.0", Some(155973)),
-    /// Allows defining c-variadic naked functions with any extern ABI that is allowed
-    /// on c-variadic foreign functions.
-    (unstable, c_variadic_naked_functions, "1.93.0", Some(148767)),
     /// Allows the use of `#[cfg(contract_checks)` to check if contract checks are enabled.
     (unstable, cfg_contract_checks, "1.86.0", Some(128044)),
     /// Allows the use of `#[cfg(overflow_checks)` to check if integer overflow behaviour.

tests/ui/c-variadic/naked-invalid.rs

@@ -4,7 +4,7 @@
 //@ ignore-backends: gcc
 
 #![feature(no_core, lang_items, rustc_attrs)]
-#![feature(c_variadic_naked_functions, abi_x86_interrupt, naked_functions_rustic_abi)]
+#![feature(abi_x86_interrupt, naked_functions_rustic_abi)]
 #![crate_type = "rlib"]
 #![no_core]
 

tests/ui/c-variadic/naked.rs

@@ -1,7 +1,6 @@
 //@ run-pass
 //@ only-x86_64
 //@ only-linux
-#![feature(c_variadic_naked_functions)]
 
 #[repr(C)]
 #[derive(Debug, PartialEq)]

tests/ui/c-variadic/same-program-multiple-abis-arm.rs

@@ -2,7 +2,6 @@
 //@ only-arm
 //@ ignore-thumb (this test uses arm assembly)
 //@ only-eabihf (the assembly below requires float hardware support)
-#![feature(c_variadic_naked_functions)]
 
 // Check that multiple c-variadic calling conventions can be used in the same program.
 //

tests/ui/c-variadic/same-program-multiple-abis-x86_64.rs

@@ -1,6 +1,5 @@
 //@ run-pass
 //@ only-x86_64
-#![feature(c_variadic_naked_functions)]
 
 // Check that multiple c-variadic calling conventions can be used in the same program.
 //