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const mem::drop

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This commit is contained in:
ltdk
2025-10-14 20:39:39 -04:00
parent 235a4c083e
commit 491bc5008c
3 changed files with 35 additions and 26 deletions
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library/core/src/mem/mod.rs
+7 -2
View File
@@ -6,7 +6,7 @@
#![stable(feature = "rust1", since = "1.0.0")]
use crate::alloc::Layout;
use crate::marker::DiscriminantKind;
use crate::marker::{Destruct, DiscriminantKind};
use crate::panic::const_assert;
use crate::{clone, cmp, fmt, hash, intrinsics, ptr};
@@ -958,8 +958,13 @@ pub const fn replace<T>(dest: &mut T, src: T) -> T {
/// [`RefCell`]: crate::cell::RefCell
#[inline]
#[stable(feature = "rust1", since = "1.0.0")]
#[rustc_const_unstable(feature = "const_destruct", issue = "133214")]
#[rustc_diagnostic_item = "mem_drop"]
pub fn drop<T>(_x: T) {}
pub const fn drop<T>(_x: T)
where
T: [const] Destruct,
{
}
/// Bitwise-copies a value.
///
tests/ui/traits/next-solver/alias-bound-unsound.rs
+5 -1
View File
@@ -4,6 +4,10 @@
#![feature(trivial_bounds)]
// we use identity instead of drop because the presence of [const] Destruct means that there
// are additional bounds on the function, which result in additional errors
use std::convert::identity;
trait Foo {
type Item: Copy
where
@@ -21,7 +25,7 @@ impl Foo for () {
fn main() {
let x = String::from("hello, world");
drop(<() as Foo>::copy_me(&x));
let _ = identity(<() as Foo>::copy_me(&x));
//~^ ERROR overflow evaluating the requirement `String <: <() as Foo>::Item`
//~| ERROR overflow evaluating the requirement `<() as Foo>::Item well-formed`
//~| ERROR overflow evaluating the requirement `&<() as Foo>::Item well-formed`
tests/ui/traits/next-solver/alias-bound-unsound.stderr
+23 -23
View File
@@ -1,11 +1,11 @@
error[E0275]: overflow evaluating the requirement `String: Copy`
--> $DIR/alias-bound-unsound.rs:18:38
--> $DIR/alias-bound-unsound.rs:22:38
|
LL | type Item = String where String: Copy;
| ^^^^
|
note: the requirement `String: Copy` appears on the `impl`'s associated type `Item` but not on the corresponding trait's associated type
--> $DIR/alias-bound-unsound.rs:8:10
--> $DIR/alias-bound-unsound.rs:12:10
|
LL | trait Foo {
| --- in this trait
@@ -13,50 +13,50 @@ LL | type Item: Copy
| ^^^^ this trait's associated type doesn't have the requirement `String: Copy`
error[E0275]: overflow evaluating the requirement `String <: <() as Foo>::Item`
--> $DIR/alias-bound-unsound.rs:24:31
--> $DIR/alias-bound-unsound.rs:28:43
|
LL | drop(<() as Foo>::copy_me(&x));
| ^^
LL | let _ = identity(<() as Foo>::copy_me(&x));
| ^^
error[E0275]: overflow evaluating the requirement `<() as Foo>::Item == _`
--> $DIR/alias-bound-unsound.rs:24:10
--> $DIR/alias-bound-unsound.rs:28:22
|
LL | drop(<() as Foo>::copy_me(&x));
| ^^^^^^^^^^^^^^^^^^^^^^^^
LL | let _ = identity(<() as Foo>::copy_me(&x));
| ^^^^^^^^^^^^^^^^^^^^^^^^
error[E0275]: overflow evaluating the requirement `<() as Foo>::Item == _`
--> $DIR/alias-bound-unsound.rs:24:10
--> $DIR/alias-bound-unsound.rs:28:22
|
LL | drop(<() as Foo>::copy_me(&x));
| ^^^^^^^^^^^^^^^^^^^^^^^^
LL | let _ = identity(<() as Foo>::copy_me(&x));
| ^^^^^^^^^^^^^^^^^^^^^^^^
|
= note: duplicate diagnostic emitted due to `-Z deduplicate-diagnostics=no`
error[E0275]: overflow evaluating the requirement `&<() as Foo>::Item well-formed`
--> $DIR/alias-bound-unsound.rs:24:31
--> $DIR/alias-bound-unsound.rs:28:43
|
LL | drop(<() as Foo>::copy_me(&x));
| ^^
LL | let _ = identity(<() as Foo>::copy_me(&x));
| ^^
error[E0275]: overflow evaluating the requirement `<() as Foo>::Item well-formed`
--> $DIR/alias-bound-unsound.rs:24:10
--> $DIR/alias-bound-unsound.rs:28:22
|
LL | drop(<() as Foo>::copy_me(&x));
| ^^^^^^^^^^^^^^^^^^^^^^^^
LL | let _ = identity(<() as Foo>::copy_me(&x));
| ^^^^^^^^^^^^^^^^^^^^^^^^
error[E0275]: overflow evaluating the requirement `<() as Foo>::Item == _`
--> $DIR/alias-bound-unsound.rs:24:10
--> $DIR/alias-bound-unsound.rs:28:22
|
LL | drop(<() as Foo>::copy_me(&x));
| ^^^^^^^^^^^^^^^^^^^^^^^^
LL | let _ = identity(<() as Foo>::copy_me(&x));
| ^^^^^^^^^^^^^^^^^^^^^^^^
|
= note: duplicate diagnostic emitted due to `-Z deduplicate-diagnostics=no`
error[E0275]: overflow evaluating the requirement `<() as Foo>::Item == _`
--> $DIR/alias-bound-unsound.rs:24:31
--> $DIR/alias-bound-unsound.rs:28:43
|
LL | drop(<() as Foo>::copy_me(&x));
| ^^
LL | let _ = identity(<() as Foo>::copy_me(&x));
| ^^
error: aborting due to 8 previous errors