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Stabilize offset_of_enum #143954

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4 changes: 0 additions & 4 deletions compiler/rustc_error_codes/src/error_codes/E0795.md
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Original file line number Diff line number Diff line change
Expand Up @@ -3,8 +3,6 @@ Invalid argument for the `offset_of!` macro.
Erroneous code example:

```compile_fail,E0795
#![feature(offset_of_enum)]

let x = std::mem::offset_of!(Option<u8>, Some);
```

Expand All @@ -16,8 +14,6 @@ The offset of the contained `u8` in the `Option<u8>` can be found by specifying
the field name `0`:

```
#![feature(offset_of_enum)]

let x: usize = std::mem::offset_of!(Option<u8>, Some.0);
```

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2 changes: 2 additions & 0 deletions compiler/rustc_feature/src/accepted.rs
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Expand Up @@ -328,6 +328,8 @@ declare_features! (
(accepted, non_exhaustive, "1.40.0", Some(44109)),
/// Allows `foo.rs` as an alternative to `foo/mod.rs`.
(accepted, non_modrs_mods, "1.30.0", Some(44660)),
/// Allows using enums in offset_of!
(accepted, offset_of_enum, "CURRENT_RUSTC_VERSION", Some(120141)),
/// Allows using multiple nested field accesses in offset_of!
(accepted, offset_of_nested, "1.82.0", Some(120140)),
/// Allows the use of or-patterns (e.g., `0 | 1`).
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2 changes: 0 additions & 2 deletions compiler/rustc_feature/src/unstable.rs
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Expand Up @@ -597,8 +597,6 @@ declare_features! (
(unstable, non_exhaustive_omitted_patterns_lint, "1.57.0", Some(89554)),
/// Allows `for<T>` binders in where-clauses
(incomplete, non_lifetime_binders, "1.69.0", Some(108185)),
/// Allows using enums in offset_of!
(unstable, offset_of_enum, "1.75.0", Some(120141)),
/// Allows using fields with slice type in offset_of!
(unstable, offset_of_slice, "1.81.0", Some(126151)),
/// Allows using `#[optimize(X)]`.
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10 changes: 0 additions & 10 deletions compiler/rustc_hir_typeck/src/expr.rs
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Expand Up @@ -3847,16 +3847,6 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
let (ident, _def_scope) =
self.tcx.adjust_ident_and_get_scope(field, container_def.did(), block);

if !self.tcx.features().offset_of_enum() {
rustc_session::parse::feature_err(
&self.tcx.sess,
sym::offset_of_enum,
ident.span,
"using enums in offset_of is experimental",
)
.emit();
}

let Some((index, variant)) = container_def
.variants()
.iter_enumerated()
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1 change: 0 additions & 1 deletion library/core/src/lib.rs
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Expand Up @@ -113,7 +113,6 @@
#![feature(is_ascii_octdigit)]
#![feature(lazy_get)]
#![feature(link_cfg)]
#![feature(offset_of_enum)]
#![feature(panic_internals)]
#![feature(ptr_alignment_type)]
#![feature(ptr_metadata)]
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13 changes: 11 additions & 2 deletions library/core/src/mem/mod.rs
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Expand Up @@ -1365,7 +1365,6 @@ impl<T> SizedTypeProperties for T {}
///
/// The following unstable features expand the functionality of `offset_of!`:
///
/// * [`offset_of_enum`] — allows `enum` variants to be traversed as if they were fields.
/// * [`offset_of_slice`] — allows getting the offset of a field of type `[T]`.
///
/// # Examples
Expand All @@ -1392,10 +1391,20 @@ impl<T> SizedTypeProperties for T {}
/// struct NestedB(u8);
///
/// assert_eq!(mem::offset_of!(NestedA, b.0), 0);
///
/// #[repr(u8)]
/// enum Enum {
/// A(u8, u16),
/// B { one: u8, two: u16 },
/// }
///
/// assert_eq!(mem::offset_of!(Enum, A.0), 1);
/// assert_eq!(mem::offset_of!(Enum, B.two), 2);
///
/// assert_eq!(mem::offset_of!(Option<&u8>, Some.0), 0);
/// ```
///
/// [dynamically sized]: https://doc.rust-lang.org/reference/dynamically-sized-types.html
/// [`offset_of_enum`]: https://doc.rust-lang.org/nightly/unstable-book/language-features/offset-of-enum.html
/// [`offset_of_slice`]: https://doc.rust-lang.org/nightly/unstable-book/language-features/offset-of-slice.html
#[stable(feature = "offset_of", since = "1.77.0")]
#[allow_internal_unstable(builtin_syntax)]
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29 changes: 0 additions & 29 deletions src/doc/unstable-book/src/language-features/offset-of-enum.md
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2 changes: 0 additions & 2 deletions tests/mir-opt/const_prop/offset_of.rs
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Expand Up @@ -2,8 +2,6 @@
//@ test-mir-pass: GVN
// EMIT_MIR_FOR_EACH_PANIC_STRATEGY

#![feature(offset_of_enum)]

use std::marker::PhantomData;
use std::mem::offset_of;

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13 changes: 0 additions & 13 deletions tests/ui/feature-gates/feature-gate-offset-of-enum.rs
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39 changes: 0 additions & 39 deletions tests/ui/feature-gates/feature-gate-offset-of-enum.stderr
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2 changes: 0 additions & 2 deletions tests/ui/layout/randomize.rs
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Expand Up @@ -2,8 +2,6 @@
//@ revisions: normal randomize-layout
//@ [randomize-layout]compile-flags: -Zrandomize-layout -Zlayout-seed=2

#![feature(offset_of_enum)]

use std::ptr;


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2 changes: 0 additions & 2 deletions tests/ui/offset-of/offset-of-enum.rs
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Question: is this missing test coverage for array indexing cases, e.g.

#![feature(offset_of_enum)]

enum Alpha {
    One([u8; 1]),
}

fn main() {
    println!("{}", std::mem::offset_of!(Alpha, One.0[0]));
    //~^ ERROR array indexing not supported in offset_of
}

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I think that error is missing a test yes - should be easy enough to add a line as in your example to one of these files. (I won't open a separate PR for that test as it would merge-conflict with this one.)

Original file line number Diff line number Diff line change
@@ -1,5 +1,3 @@
#![feature(offset_of_enum)]

use std::mem::offset_of;

enum Alpha {
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12 changes: 6 additions & 6 deletions tests/ui/offset-of/offset-of-enum.stderr
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Original file line number Diff line number Diff line change
@@ -1,5 +1,5 @@
error[E0573]: expected type, found variant `Alpha::One`
--> $DIR/offset-of-enum.rs:11:16
--> $DIR/offset-of-enum.rs:9:16
|
LL | offset_of!(Alpha::One, 0);
| ^^^^^^^^^^
Expand All @@ -8,35 +8,35 @@ LL | offset_of!(Alpha::One, 0);
| help: try using the variant's enum: `Alpha`

error[E0412]: cannot find type `Beta` in this scope
--> $DIR/offset-of-enum.rs:17:16
--> $DIR/offset-of-enum.rs:15:16
|
LL | offset_of!(Beta, One);
| ^^^^ not found in this scope

error[E0795]: `One` is an enum variant; expected field at end of `offset_of`
--> $DIR/offset-of-enum.rs:12:23
--> $DIR/offset-of-enum.rs:10:23
|
LL | offset_of!(Alpha, One);
| ^^^ enum variant

error[E0609]: no field named `1` on enum variant `Alpha::Two`
--> $DIR/offset-of-enum.rs:14:23
--> $DIR/offset-of-enum.rs:12:23
|
LL | offset_of!(Alpha, Two.1);
| ^^^ - ...does not have this field
| |
| this enum variant...

error[E0609]: no field named `foo` on enum variant `Alpha::Two`
--> $DIR/offset-of-enum.rs:15:23
--> $DIR/offset-of-enum.rs:13:23
|
LL | offset_of!(Alpha, Two.foo);
| ^^^ --- ...does not have this field
| |
| this enum variant...

error[E0599]: no variant named `NonExistent` found for enum `Alpha`
--> $DIR/offset-of-enum.rs:16:23
--> $DIR/offset-of-enum.rs:14:23
|
LL | offset_of!(Alpha, NonExistent);
| ^^^^^^^^^^^ variant not found
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4 changes: 1 addition & 3 deletions tests/ui/offset-of/offset-of-private.rs
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Original file line number Diff line number Diff line change
@@ -1,5 +1,3 @@
#![feature(offset_of_enum)]

use std::mem::offset_of;

mod m {
Expand Down Expand Up @@ -31,7 +29,7 @@ fn main() {
offset_of!(m::FooTuple, 1); //~ ERROR field `1` of struct `FooTuple` is private
offset_of!(m::Bar, public); //~ ERROR struct `Bar` is private
offset_of!(m::Bar, private); //~ ERROR struct `Bar` is private
//~| ERROR field `private` of struct `Bar` is private
//~^ ERROR field `private` of struct `Bar` is private

offset_of!(m::Baz, Var1.0.public);
offset_of!(m::Baz, Var1.0.private); //~ ERROR field `private` of struct `Foo` is private
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16 changes: 8 additions & 8 deletions tests/ui/offset-of/offset-of-private.stderr
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@@ -1,47 +1,47 @@
error[E0603]: struct `Bar` is private
--> $DIR/offset-of-private.rs:32:19
--> $DIR/offset-of-private.rs:30:19
|
LL | offset_of!(m::Bar, public);
| ^^^ private struct
|
note: the struct `Bar` is defined here
--> $DIR/offset-of-private.rs:16:5
--> $DIR/offset-of-private.rs:14:5
|
LL | struct Bar {
| ^^^^^^^^^^

error[E0603]: struct `Bar` is private
--> $DIR/offset-of-private.rs:33:19
--> $DIR/offset-of-private.rs:31:19
|
LL | offset_of!(m::Bar, private);
| ^^^ private struct
|
note: the struct `Bar` is defined here
--> $DIR/offset-of-private.rs:16:5
--> $DIR/offset-of-private.rs:14:5
|
LL | struct Bar {
| ^^^^^^^^^^

error[E0616]: field `private` of struct `Foo` is private
--> $DIR/offset-of-private.rs:29:24
--> $DIR/offset-of-private.rs:27:24
|
LL | offset_of!(m::Foo, private);
| ^^^^^^^ private field

error[E0616]: field `1` of struct `FooTuple` is private
--> $DIR/offset-of-private.rs:31:29
--> $DIR/offset-of-private.rs:29:29
|
LL | offset_of!(m::FooTuple, 1);
| ^ private field

error[E0616]: field `private` of struct `Bar` is private
--> $DIR/offset-of-private.rs:33:24
--> $DIR/offset-of-private.rs:31:24
|
LL | offset_of!(m::Bar, private);
| ^^^^^^^ private field

error[E0616]: field `private` of struct `Foo` is private
--> $DIR/offset-of-private.rs:37:31
--> $DIR/offset-of-private.rs:35:31
|
LL | offset_of!(m::Baz, Var1.0.private);
| ^^^^^^^ private field
Expand Down
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