Stabilize const_refs_to_static

Author: dingxiangfei2009

compiler/rustc_const_eval/src/check_consts/check.rs

@@ -355,7 +355,6 @@ impl<'mir, 'tcx> Checker<'mir, 'tcx> {
         {
             self.error_emitted = Some(guar);
         }
-        self.check_op_spanned(ops::StaticAccess, span)
     }
 
     fn check_local_or_return_ty(&mut self, ty: Ty<'tcx>, local: Local) {

compiler/rustc_const_eval/src/check_consts/ops.rs

@@ -553,33 +553,6 @@ impl<'tcx> NonConstOp<'tcx> for RawPtrToIntCast {
     }
 }
 
-/// An access to a (non-thread-local) `static`.
-#[derive(Debug)]
-pub(crate) struct StaticAccess;
-impl<'tcx> NonConstOp<'tcx> for StaticAccess {
-    fn status_in_item(&self, ccx: &ConstCx<'_, 'tcx>) -> Status {
-        if let hir::ConstContext::Static(_) = ccx.const_kind() {
-            Status::Allowed
-        } else {
-            Status::Unstable(sym::const_refs_to_static)
-        }
-    }
-
-    #[allow(rustc::untranslatable_diagnostic)] // FIXME: make this translatable
-    fn build_error(&self, ccx: &ConstCx<'_, 'tcx>, span: Span) -> Diag<'tcx> {
-        let mut err = feature_err(
-            &ccx.tcx.sess,
-            sym::const_refs_to_static,
-            span,
-            format!("referencing statics in {}s is unstable", ccx.const_kind(),),
-        );
-        err
-            .note("`static` and `const` variables can refer to other `const` variables. A `const` variable, however, cannot refer to a `static` variable.")
-            .help("to fix this, the value can be extracted to a `const` and then used.");
-        err
-    }
-}
-
 /// An access to a thread-local `static`.
 #[derive(Debug)]
 pub(crate) struct ThreadLocalAccess;

compiler/rustc_error_codes/src/error_codes/E0013.md

@@ -5,7 +5,7 @@ variable cannot refer to a static variable.
 
 Erroneous code example:
 
-```compile_fail,E0658
+```
 static X: i32 = 42;
 const Y: i32 = X;
 ```

compiler/rustc_feature/src/accepted.rs

@@ -145,6 +145,8 @@ declare_features! (
     (accepted, const_panic, "1.57.0", Some(51999)),
     /// Allows dereferencing raw pointers during const eval.
     (accepted, const_raw_ptr_deref, "1.58.0", Some(51911)),
+    /// Allows creating pointers and references to `static` items in constants.
+    (accepted, const_refs_to_static, "CURRENT_RUSTC_VERSION", Some(119618)),
     /// Allows implementing `Copy` for closures where possible (RFC 2132).
     (accepted, copy_closures, "1.26.0", Some(44490)),
     /// Allows `crate` in paths.

compiler/rustc_feature/src/unstable.rs

@@ -413,8 +413,6 @@ declare_features! (
     (unstable, const_precise_live_drops, "1.46.0", Some(73255)),
     /// Allows references to types with interior mutability within constants
     (unstable, const_refs_to_cell, "1.51.0", Some(80384)),
-    /// Allows creating pointers and references to `static` items in constants.
-    (unstable, const_refs_to_static, "1.78.0", Some(119618)),
     /// Allows `impl const Trait for T` syntax.
     (unstable, const_trait_impl, "1.42.0", Some(67792)),
     /// Allows the `?` operator in const contexts.

tests/ui/asm/const-refs-to-static.rs

@@ -2,8 +2,6 @@
 //@ ignore-nvptx64
 //@ ignore-spirv
 
-#![feature(const_refs_to_static)]
-
 use std::arch::{asm, global_asm};
 use std::ptr::addr_of;
 

tests/ui/asm/const-refs-to-static.stderr

@@ -1,5 +1,5 @@
 error: invalid type for `const` operand
-  --> $DIR/const-refs-to-static.rs:12:19
+  --> $DIR/const-refs-to-static.rs:10:19
    |
 LL | global_asm!("{}", const addr_of!(FOO));
    |                   ^^^^^^-------------
@@ -9,7 +9,7 @@ LL | global_asm!("{}", const addr_of!(FOO));
    = help: `const` operands must be of an integer type
 
 error: invalid type for `const` operand
-  --> $DIR/const-refs-to-static.rs:17:25
+  --> $DIR/const-refs-to-static.rs:15:25
    |
 LL |     unsafe { asm!("{}", const addr_of!(FOO)) };
    |                         ^^^^^^-------------

tests/ui/asm/x86_64/type-check-4.rs

@@ -1,14 +1,12 @@
 //@ only-x86_64
 //@ compile-flags: -C target-feature=+avx512f
-
-use std::arch::{asm, global_asm};
+//@ check-pass
 
 use std::arch::x86_64::{_mm256_setzero_ps, _mm_setzero_ps};
+use std::arch::{asm, global_asm};
 
 fn main() {}
 
-// Constants must be... constant
-
 static S: i32 = 1;
 const fn const_foo(x: i32) -> i32 {
     x
@@ -17,10 +15,7 @@ const fn const_bar<T>(x: T) -> T {
     x
 }
 global_asm!("{}", const S);
-//~^ ERROR referencing statics
 global_asm!("{}", const const_foo(0));
 global_asm!("{}", const const_foo(S));
-//~^ ERROR referencing statics
 global_asm!("{}", const const_bar(0));
 global_asm!("{}", const const_bar(S));
-//~^ ERROR referencing statics

tests/ui/asm/x86_64/type-check-4.stderr

@@ -1,39 +1,6 @@
-error[E0658]: referencing statics in constants is unstable
-  --> $DIR/type-check-4.rs:19:25
+warning: unstable feature specified for `-Ctarget-feature`: `avx512f`
    |
-LL | global_asm!("{}", const S);
-   |                         ^
-   |
-   = note: see issue #119618 <https://github.com/rust-lang/rust/issues/119618> for more information
-   = help: add `#![feature(const_refs_to_static)]` to the crate attributes to enable
-   = note: this compiler was built on YYYY-MM-DD; consider upgrading it if it is out of date
-   = note: `static` and `const` variables can refer to other `const` variables. A `const` variable, however, cannot refer to a `static` variable.
-   = help: to fix this, the value can be extracted to a `const` and then used.
-
-error[E0658]: referencing statics in constants is unstable
-  --> $DIR/type-check-4.rs:22:35
-   |
-LL | global_asm!("{}", const const_foo(S));
-   |                                   ^
-   |
-   = note: see issue #119618 <https://github.com/rust-lang/rust/issues/119618> for more information
-   = help: add `#![feature(const_refs_to_static)]` to the crate attributes to enable
-   = note: this compiler was built on YYYY-MM-DD; consider upgrading it if it is out of date
-   = note: `static` and `const` variables can refer to other `const` variables. A `const` variable, however, cannot refer to a `static` variable.
-   = help: to fix this, the value can be extracted to a `const` and then used.
-
-error[E0658]: referencing statics in constants is unstable
-  --> $DIR/type-check-4.rs:25:35
-   |
-LL | global_asm!("{}", const const_bar(S));
-   |                                   ^
-   |
-   = note: see issue #119618 <https://github.com/rust-lang/rust/issues/119618> for more information
-   = help: add `#![feature(const_refs_to_static)]` to the crate attributes to enable
-   = note: this compiler was built on YYYY-MM-DD; consider upgrading it if it is out of date
-   = note: `static` and `const` variables can refer to other `const` variables. A `const` variable, however, cannot refer to a `static` variable.
-   = help: to fix this, the value can be extracted to a `const` and then used.
+   = note: this feature is not stably supported; its behavior can change in the future
 
-error: aborting due to 3 previous errors
+warning: 1 warning emitted
 
-For more information about this error, try `rustc --explain E0658`.

tests/ui/consts/const-fn-not-safe-for-const.rs

@@ -18,12 +18,10 @@ static Y: u32 = 0;
 
 const fn get_Y() -> u32 {
     Y
-    //~^ ERROR referencing statics in constant functions
 }
 
 const fn get_Y_addr() -> &'static u32 {
     &Y
-    //~^ ERROR referencing statics in constant functions
 }
 
 const fn get() -> u32 {