Stabilize const_refs_to_static

rust-lang · Aug 29, 2024 · c100748 · c100748
1 parent 784d444
commit c100748
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Showing 36 changed files with 91 additions and 445 deletions.
diff --git a/compiler/rustc_const_eval/src/check_consts/check.rs b/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) {

diff --git a/compiler/rustc_const_eval/src/check_consts/ops.rs b/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 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 struct ThreadLocalAccess;

diff --git a/compiler/rustc_feature/src/accepted.rs b/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.

diff --git a/compiler/rustc_feature/src/unstable.rs b/compiler/rustc_feature/src/unstable.rs
@@ -411,8 +411,6 @@ 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.

diff --git a/tests/ui/abi/c-zst.other.stderr b/tests/ui/abi/c-zst.other.stderr
@@ -1,67 +1,11 @@
-error: fn_abi_of(pass_zst) = FnAbi {
-           args: [
-               ArgAbi {
-                   layout: TyAndLayout {
-                       ty: (),
-                       layout: Layout {
-                           size: Size(0 bytes),
-                           align: AbiAndPrefAlign {
-                               abi: $SOME_ALIGN,
-                               pref: $SOME_ALIGN,
-                           },
-                           abi: Aggregate {
-                               sized: true,
-                           },
-                           fields: Arbitrary {
-                               offsets: [],
-                               memory_index: [],
-                           },
-                           largest_niche: None,
-                           variants: Single {
-                               index: 0,
-                           },
-                           max_repr_align: None,
-                           unadjusted_abi_align: $SOME_ALIGN,
-                       },
-                   },
-                   mode: Ignore,
-               },
-           ],
-           ret: ArgAbi {
-               layout: TyAndLayout {
-                   ty: (),
-                   layout: Layout {
-                       size: Size(0 bytes),
-                       align: AbiAndPrefAlign {
-                           abi: $SOME_ALIGN,
-                           pref: $SOME_ALIGN,
-                       },
-                       abi: Aggregate {
-                           sized: true,
-                       },
-                       fields: Arbitrary {
-                           offsets: [],
-                           memory_index: [],
-                       },
-                       largest_niche: None,
-                       variants: Single {
-                           index: 0,
-                       },
-                       max_repr_align: None,
-                       unadjusted_abi_align: $SOME_ALIGN,
-                   },
-               },
-               mode: Ignore,
-           },
-           c_variadic: false,
-           fixed_count: 1,
-           conv: C,
-           can_unwind: false,
-       }
-  --> $DIR/c-zst.rs:27:1
+error[E0463]: can't find crate for `std`
    |
-LL | extern "C" fn pass_zst(_: ()) {}
-   | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+   = note: the `riscv64imac-unknown-none-elf` target may not support the standard library
+   = note: `std` is required by `<unknown>` because it does not declare `#![no_std]`
+   = help: consider building the standard library from source with `cargo build -Zbuild-std`
 
-error: aborting due to 1 previous error
+error: requires `sized` lang_item
 
+error: aborting due to 2 previous errors
+
+For more information about this error, try `rustc --explain E0463`.
diff --git a/tests/ui/asm/x86_64/type-check-4.rs b/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
diff --git a/tests/ui/asm/x86_64/type-check-4.stderr b/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`.
diff --git a/tests/ui/consts/const-fn-not-safe-for-const.rs b/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 {

diff --git a/tests/ui/consts/const-fn-not-safe-for-const.stderr b/tests/ui/consts/const-fn-not-safe-for-const.stderr
@@ -6,31 +6,6 @@ LL |     random()
    |
    = note: calls in constant functions are limited to constant functions, tuple structs and tuple variants
 
-error[E0658]: referencing statics in constant functions is unstable
-  --> $DIR/const-fn-not-safe-for-const.rs:20:5
-   |
-LL |     Y
-   |     ^
-   |
-   = 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 constant functions is unstable
-  --> $DIR/const-fn-not-safe-for-const.rs:25:6
-   |
-LL |     &Y
-   |      ^
-   |
-   = 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: aborting due to 3 previous errors
+error: aborting due to 1 previous error
 
-Some errors have detailed explanations: E0015, E0658.
-For more information about an error, try `rustc --explain E0015`.
+For more information about this error, try `rustc --explain E0015`.
diff --git a/tests/ui/consts/const-mut-refs/mut_ref_in_final_dynamic_check.rs b/tests/ui/consts/const-mut-refs/mut_ref_in_final_dynamic_check.rs
@@ -1,7 +1,7 @@
 //@ normalize-stderr-test: "(the raw bytes of the constant) \(size: [0-9]*, align: [0-9]*\)" -> "$1 (size: $$SIZE, align: $$ALIGN)"
 //@ normalize-stderr-test: "( 0x[0-9a-f][0-9a-f] │)? ([0-9a-f][0-9a-f] |__ |╾─*ALLOC[0-9]+(\+[a-z0-9]+)?(<imm>)?─*╼ )+ *│.*" -> " HEX_DUMP"
 //@ normalize-stderr-test: "HEX_DUMP\s*\n\s*HEX_DUMP" -> "HEX_DUMP"
-#![feature(const_mut_refs, const_refs_to_static)]
+#![feature(const_mut_refs)]
 
 use std::sync::Mutex;
 

diff --git a/tests/ui/consts/const-ref-to-static-linux-vtable.rs b/tests/ui/consts/const-ref-to-static-linux-vtable.rs
@@ -1,6 +1,6 @@
-//@check-pass
+//@ check-pass
 //! This is the reduced version of the "Linux kernel vtable" use-case.
-#![feature(const_mut_refs, const_refs_to_static)]
+#![feature(const_mut_refs)]
 use std::ptr::addr_of_mut;
 
 #[repr(C)]

diff --git a/tests/ui/consts/const_refs_to_static-ice-121413.rs b/tests/ui/consts/const_refs_to_static-ice-121413.rs
@@ -3,7 +3,6 @@
 // issue: rust-lang/rust#121413
 //@ compile-flags: -Zextra-const-ub-checks
 // ignore-tidy-linelength
-#![feature(const_refs_to_static)]
 const REF_INTERIOR_MUT: &usize = {
     //~^ HELP consider importing this struct
     static FOO: Sync = AtomicUsize::new(0);

diff --git a/tests/ui/consts/const_refs_to_static-ice-121413.stderr b/tests/ui/consts/const_refs_to_static-ice-121413.stderr
@@ -1,5 +1,5 @@
 error[E0433]: failed to resolve: use of undeclared type `AtomicUsize`
-  --> $DIR/const_refs_to_static-ice-121413.rs:9:24
+  --> $DIR/const_refs_to_static-ice-121413.rs:8:24
    |
 LL |     static FOO: Sync = AtomicUsize::new(0);
    |                        ^^^^^^^^^^^ use of undeclared type `AtomicUsize`
@@ -10,7 +10,7 @@ LL + use std::sync::atomic::AtomicUsize;
    |
 
 warning: trait objects without an explicit `dyn` are deprecated
-  --> $DIR/const_refs_to_static-ice-121413.rs:9:17
+  --> $DIR/const_refs_to_static-ice-121413.rs:8:17
    |
 LL |     static FOO: Sync = AtomicUsize::new(0);
    |                 ^^^^
@@ -24,15 +24,15 @@ LL |     static FOO: dyn Sync = AtomicUsize::new(0);
    |                 +++
 
 error[E0277]: the size for values of type `(dyn Sync + 'static)` cannot be known at compilation time
-  --> $DIR/const_refs_to_static-ice-121413.rs:9:17
+  --> $DIR/const_refs_to_static-ice-121413.rs:8:17
    |
 LL |     static FOO: Sync = AtomicUsize::new(0);
    |                 ^^^^ doesn't have a size known at compile-time
    |
    = help: the trait `Sized` is not implemented for `(dyn Sync + 'static)`
 
 error[E0277]: the size for values of type `(dyn Sync + 'static)` cannot be known at compilation time
-  --> $DIR/const_refs_to_static-ice-121413.rs:9:24
+  --> $DIR/const_refs_to_static-ice-121413.rs:8:24
    |
 LL |     static FOO: Sync = AtomicUsize::new(0);
    |                        ^^^^^^^^^^^^^^^^^^^ doesn't have a size known at compile-time

diff --git a/tests/ui/consts/const_refs_to_static.rs b/tests/ui/consts/const_refs_to_static.rs
@@ -1,5 +1,4 @@
 //@ run-pass
-#![feature(const_refs_to_static)]
 
 static S: i32 = 0;
 static mut S_MUT: i32 = 0;

diff --git a/tests/ui/consts/const_refs_to_static_fail.rs b/tests/ui/consts/const_refs_to_static_fail.rs
@@ -1,6 +1,6 @@
 //@ normalize-stderr-test: "(the raw bytes of the constant) \(size: [0-9]*, align: [0-9]*\)" -> "$1 (size: $$SIZE, align: $$ALIGN)"
 //@ normalize-stderr-test: "([0-9a-f][0-9a-f] |╾─*ALLOC[0-9]+(\+[a-z0-9]+)?(<imm>)?─*╼ )+ *│.*" -> "HEX_DUMP"
-#![feature(const_refs_to_static, const_mut_refs, sync_unsafe_cell)]
+#![feature(const_mut_refs, sync_unsafe_cell)]
 use std::cell::SyncUnsafeCell;
 
 static S: SyncUnsafeCell<i32> = SyncUnsafeCell::new(0);

diff --git a/tests/ui/consts/const_refs_to_static_fail_invalid.rs b/tests/ui/consts/const_refs_to_static_fail_invalid.rs
@@ -1,6 +1,5 @@
 //@ normalize-stderr-test: "(the raw bytes of the constant) \(size: [0-9]*, align: [0-9]*\)" -> "$1 (size: $$SIZE, align: $$ALIGN)"
 //@ normalize-stderr-test: "([0-9a-f][0-9a-f] |╾─*ALLOC[0-9]+(\+[a-z0-9]+)?(<imm>)?─*╼ )+ *│.*" -> "HEX_DUMP"
-#![feature(const_refs_to_static)]
 #![allow(static_mut_refs)]
 
 fn invalid() {

diff --git a/tests/ui/consts/const_refs_to_static_fail_invalid.stderr b/tests/ui/consts/const_refs_to_static_fail_invalid.stderr
@@ -1,5 +1,5 @@
 error[E0080]: it is undefined behavior to use this value
-  --> $DIR/const_refs_to_static_fail_invalid.rs:9:5
+  --> $DIR/const_refs_to_static_fail_invalid.rs:8:5
    |
 LL |     const C: &bool = unsafe { std::mem::transmute(&S) };
    |     ^^^^^^^^^^^^^^ constructing invalid value at .<deref>: encountered 0x0a, but expected a boolean
@@ -10,7 +10,7 @@ LL |     const C: &bool = unsafe { std::mem::transmute(&S) };
            }
 
 error[E0080]: it is undefined behavior to use this value
-  --> $DIR/const_refs_to_static_fail_invalid.rs:25:5
+  --> $DIR/const_refs_to_static_fail_invalid.rs:24:5
    |
 LL |     const C: &i8 = unsafe { &S };
    |     ^^^^^^^^^^^^ constructing invalid value: encountered reference to `extern` static in `const`
@@ -21,7 +21,7 @@ LL |     const C: &i8 = unsafe { &S };
            }
 
 error[E0080]: it is undefined behavior to use this value
-  --> $DIR/const_refs_to_static_fail_invalid.rs:39:5
+  --> $DIR/const_refs_to_static_fail_invalid.rs:38:5
    |
 LL |     const C: &i32 = unsafe { &S_MUT };
    |     ^^^^^^^^^^^^^ constructing invalid value: encountered reference to mutable memory in `const`
@@ -32,19 +32,19 @@ LL |     const C: &i32 = unsafe { &S_MUT };
            }
 
 error: could not evaluate constant pattern
-  --> $DIR/const_refs_to_static_fail_invalid.rs:15:9
+  --> $DIR/const_refs_to_static_fail_invalid.rs:14:9
    |
 LL |         C => {}
    |         ^
 
 error: could not evaluate constant pattern
-  --> $DIR/const_refs_to_static_fail_invalid.rs:31:9
+  --> $DIR/const_refs_to_static_fail_invalid.rs:30:9
    |
 LL |         C => {}
    |         ^
 
 error: could not evaluate constant pattern
-  --> $DIR/const_refs_to_static_fail_invalid.rs:46:9
+  --> $DIR/const_refs_to_static_fail_invalid.rs:45:9
    |
 LL |         C => {}
    |         ^

diff --git a/tests/ui/consts/issue-17718-const-bad-values.rs b/tests/ui/consts/issue-17718-const-bad-values.rs
@@ -5,7 +5,6 @@ const C1: &'static mut [usize] = &mut [];
 
 static mut S: usize = 3;
 const C2: &'static mut usize = unsafe { &mut S };
-//~^ ERROR: referencing statics in constants
-//~| ERROR: mutable references are not allowed
+//~^ ERROR: mutable references are not allowed in constants
 
 fn main() {}