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revert: PR144016 - MetaSized does not always hold

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This commit is contained in:
David Wood 2025-07-17 09:10:37 +00:00
parent 235a4c083e
commit efaeacfc96
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23 changed files with 294 additions and 45 deletions
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7
compiler/rustc_trait_selection/src/traits/util.rs
View file

@ -383,13 +383,6 @@ pub fn sizedness_fast_path<'tcx>(
_ => return false,
};
// FIXME(sized_hierarchy): this temporarily reverts the `sized_hierarchy` feature
// while a proper fix for `tests/ui/sized-hierarchy/incomplete-inference-issue-143992.rs`
// is pending a proper fix
if !tcx.features().sized_hierarchy() && matches!(sizedness, SizedTraitKind::MetaSized) {
return true;
}
if trait_pred.self_ty().has_trivial_sizedness(tcx, sizedness) {
debug!("fast path -- trivial sizedness");
return true;

4
tests/ui/consts/const-size_of_val-align_of_val-extern-type.rs
View file

@ -8,8 +8,8 @@ extern "C" {
}
const _SIZE: usize = unsafe { size_of_val(&4 as *const i32 as *const Opaque) };
//~^ ERROR `extern type` does not have known layout
//~^ ERROR: the size for values of type `Opaque` cannot be known
const _ALIGN: usize = unsafe { align_of_val(&4 as *const i32 as *const Opaque) };
//~^ ERROR `extern type` does not have known layout
//~^ ERROR: the size for values of type `Opaque` cannot be known
fn main() {}

38
tests/ui/consts/const-size_of_val-align_of_val-extern-type.stderr
View file

@ -1,15 +1,39 @@
error[E0080]: `extern type` does not have known layout
--> $DIR/const-size_of_val-align_of_val-extern-type.rs:10:31
error[E0277]: the size for values of type `Opaque` cannot be known
--> $DIR/const-size_of_val-align_of_val-extern-type.rs:10:43
|
LL | const _SIZE: usize = unsafe { size_of_val(&4 as *const i32 as *const Opaque) };
| ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ evaluation of `_SIZE` failed here
| ----------- ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ the trait `MetaSized` is not implemented for `Opaque`
| |
| required by a bound introduced by this call
|
= note: the trait bound `Opaque: MetaSized` is not satisfied
note: required by a bound in `std::intrinsics::size_of_val`
--> $SRC_DIR/core/src/intrinsics/mod.rs:LL:COL
help: consider borrowing here
|
LL | const _SIZE: usize = unsafe { size_of_val(&(&4 as *const i32 as *const Opaque)) };
| ++ +
LL | const _SIZE: usize = unsafe { size_of_val(&mut (&4 as *const i32 as *const Opaque)) };
| ++++++ +
error[E0080]: `extern type` does not have known layout
--> $DIR/const-size_of_val-align_of_val-extern-type.rs:12:32
error[E0277]: the size for values of type `Opaque` cannot be known
--> $DIR/const-size_of_val-align_of_val-extern-type.rs:12:45
|
LL | const _ALIGN: usize = unsafe { align_of_val(&4 as *const i32 as *const Opaque) };
| ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ evaluation of `_ALIGN` failed here
| ------------ ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ the trait `MetaSized` is not implemented for `Opaque`
| |
| required by a bound introduced by this call
|
= note: the trait bound `Opaque: MetaSized` is not satisfied
note: required by a bound in `std::intrinsics::align_of_val`
--> $SRC_DIR/core/src/intrinsics/mod.rs:LL:COL
help: consider borrowing here
|
LL | const _ALIGN: usize = unsafe { align_of_val(&(&4 as *const i32 as *const Opaque)) };
| ++ +
LL | const _ALIGN: usize = unsafe { align_of_val(&mut (&4 as *const i32 as *const Opaque)) };
| ++++++ +
error: aborting due to 2 previous errors
For more information about this error, try `rustc --explain E0080`.
For more information about this error, try `rustc --explain E0277`.

5
tests/ui/extern/extern-types-size_of_val.rs vendored
View file

@ -1,8 +1,9 @@
//@ check-pass
#![feature(extern_types)]
use std::mem::{align_of_val, size_of_val};
// Check that calls to `size_of_val` and `align_of_val` with extern types are not accepted
extern "C" {
type A;
}
@ -11,5 +12,7 @@ fn main() {
let x: &A = unsafe { &*(1usize as *const A) };
size_of_val(x);
//~^ ERROR: the size for values of type `A` cannot be known
align_of_val(x);
//~^ ERROR: the size for values of type `A` cannot be known
}

39
tests/ui/extern/extern-types-size_of_val.stderr vendored Normal file
View file

@ -0,0 +1,39 @@
error[E0277]: the size for values of type `A` cannot be known
--> $DIR/extern-types-size_of_val.rs:14:17
|
LL | size_of_val(x);
| ----------- ^ the trait `MetaSized` is not implemented for `A`
| |
| required by a bound introduced by this call
|
= note: the trait bound `A: MetaSized` is not satisfied
note: required by a bound in `std::mem::size_of_val`
--> $SRC_DIR/core/src/mem/mod.rs:LL:COL
help: consider borrowing here
|
LL | size_of_val(&x);
| +
LL | size_of_val(&mut x);
| ++++
error[E0277]: the size for values of type `A` cannot be known
--> $DIR/extern-types-size_of_val.rs:16:18
|
LL | align_of_val(x);
| ------------ ^ the trait `MetaSized` is not implemented for `A`
| |
| required by a bound introduced by this call
|
= note: the trait bound `A: MetaSized` is not satisfied
note: required by a bound in `std::mem::align_of_val`
--> $SRC_DIR/core/src/mem/mod.rs:LL:COL
help: consider borrowing here
|
LL | align_of_val(&x);
| +
LL | align_of_val(&mut x);
| ++++
error: aborting due to 2 previous errors
For more information about this error, try `rustc --explain E0277`.

2
tests/ui/extern/extern-types-unsized.rs vendored
View file

@ -27,7 +27,9 @@ fn main() {
assert_sized::<Bar<A>>();
//~^ ERROR the size for values of type
//~| ERROR the size for values of type `A` cannot be known
assert_sized::<Bar<Bar<A>>>();
//~^ ERROR the size for values of type
//~| ERROR the size for values of type `A` cannot be known
}

30
tests/ui/extern/extern-types-unsized.stderr vendored
View file

@ -59,8 +59,21 @@ help: consider relaxing the implicit `Sized` restriction
LL | fn assert_sized<T: ?Sized>() {}
| ++++++++
error[E0277]: the size for values of type `A` cannot be known
--> $DIR/extern-types-unsized.rs:28:20
|
LL | assert_sized::<Bar<A>>();
| ^^^^^^ doesn't have a known size
|
= help: the trait `MetaSized` is not implemented for `A`
note: required by a bound in `Bar`
--> $DIR/extern-types-unsized.rs:14:12
|
LL | struct Bar<T: ?Sized> {
| ^ required by this bound in `Bar`
error[E0277]: the size for values of type `A` cannot be known at compilation time
--> $DIR/extern-types-unsized.rs:31:20
--> $DIR/extern-types-unsized.rs:32:20
|
LL | assert_sized::<Bar<Bar<A>>>();
| ^^^^^^^^^^^ doesn't have a size known at compile-time
@ -81,6 +94,19 @@ help: consider relaxing the implicit `Sized` restriction
LL | fn assert_sized<T: ?Sized>() {}
| ++++++++
error: aborting due to 4 previous errors
error[E0277]: the size for values of type `A` cannot be known
--> $DIR/extern-types-unsized.rs:32:20
|
LL | assert_sized::<Bar<Bar<A>>>();
| ^^^^^^^^^^^ doesn't have a known size
|
= help: the trait `MetaSized` is not implemented for `A`
note: required by a bound in `Bar`
--> $DIR/extern-types-unsized.rs:14:12
|
LL | struct Bar<T: ?Sized> {
| ^ required by this bound in `Bar`
error: aborting due to 6 previous errors
For more information about this error, try `rustc --explain E0277`.

4
tests/ui/extern/unsized-extern-derefmove.rs vendored
View file

@ -7,10 +7,14 @@ extern "C" {
}
unsafe fn make_device() -> Box<Device> {
//~^ ERROR the size for values of type `Device` cannot be known
Box::from_raw(0 as *mut _)
//~^ ERROR the size for values of type `Device` cannot be known
//~| ERROR the size for values of type `Device` cannot be known
}
fn main() {
let d: Device = unsafe { *make_device() };
//~^ ERROR the size for values of type `Device` cannot be known
//~| ERROR the size for values of type `Device` cannot be known
}

52
tests/ui/extern/unsized-extern-derefmove.stderr vendored
View file

@ -1,5 +1,43 @@
error[E0277]: the size for values of type `Device` cannot be known
--> $DIR/unsized-extern-derefmove.rs:9:28
|
LL | unsafe fn make_device() -> Box<Device> {
| ^^^^^^^^^^^ doesn't have a known size
|
= help: the trait `MetaSized` is not implemented for `Device`
note: required by a bound in `Box`
--> $SRC_DIR/alloc/src/boxed.rs:LL:COL
error[E0277]: the size for values of type `Device` cannot be known
--> $DIR/unsized-extern-derefmove.rs:11:19
|
LL | Box::from_raw(0 as *mut _)
| ------------- ^^^^^^^^^^^ the trait `MetaSized` is not implemented for `Device`
| |
| required by a bound introduced by this call
|
= note: the trait bound `Device: MetaSized` is not satisfied
note: required by a bound in `Box::<T>::from_raw`
--> $SRC_DIR/alloc/src/boxed.rs:LL:COL
help: consider borrowing here
|
LL | Box::from_raw(&(0 as *mut _))
| ++ +
LL | Box::from_raw(&mut (0 as *mut _))
| ++++++ +
error[E0277]: the size for values of type `Device` cannot be known
--> $DIR/unsized-extern-derefmove.rs:11:5
|
LL | Box::from_raw(0 as *mut _)
| ^^^^^^^^^^^^^^^^^^^^^^^^^^ doesn't have a known size
|
= help: the trait `MetaSized` is not implemented for `Device`
note: required by a bound in `Box`
--> $SRC_DIR/alloc/src/boxed.rs:LL:COL
error[E0277]: the size for values of type `Device` cannot be known at compilation time
--> $DIR/unsized-extern-derefmove.rs:14:9
--> $DIR/unsized-extern-derefmove.rs:17:9
|
LL | let d: Device = unsafe { *make_device() };
| ^ doesn't have a size known at compile-time
@ -11,6 +49,16 @@ help: consider borrowing here
LL | let d: &Device = unsafe { *make_device() };
| +
error: aborting due to 1 previous error
error[E0277]: the size for values of type `Device` cannot be known
--> $DIR/unsized-extern-derefmove.rs:17:31
|
LL | let d: Device = unsafe { *make_device() };
| ^^^^^^^^^^^^^ doesn't have a known size
|
= help: the trait `MetaSized` is not implemented for `Device`
note: required by a bound in `Box`
--> $SRC_DIR/alloc/src/boxed.rs:LL:COL
error: aborting due to 5 previous errors
For more information about this error, try `rustc --explain E0277`.

1
tests/ui/layout/unconstrained-param-ice-137308.rs
View file

@ -17,3 +17,4 @@ impl<C: ?Sized> A for u8 { //~ ERROR: the type parameter `C` is not constrained
#[rustc_layout(debug)]
struct S([u8; <u8 as A>::B]);
//~^ ERROR: the type has an unknown layout
//~| ERROR: type annotations needed

11
tests/ui/layout/unconstrained-param-ice-137308.stderr
View file

@ -4,12 +4,19 @@ error[E0207]: the type parameter `C` is not constrained by the impl trait, self
LL | impl<C: ?Sized> A for u8 {
| ^ unconstrained type parameter
error[E0282]: type annotations needed
--> $DIR/unconstrained-param-ice-137308.rs:18:16
|
LL | struct S([u8; <u8 as A>::B]);
| ^^ cannot infer type for type parameter `C`
error: the type has an unknown layout
--> $DIR/unconstrained-param-ice-137308.rs:18:1
|
LL | struct S([u8; <u8 as A>::B]);
| ^^^^^^^^
error: aborting due to 2 previous errors
error: aborting due to 3 previous errors
For more information about this error, try `rustc --explain E0207`.
Some errors have detailed explanations: E0207, E0282.
For more information about an error, try `rustc --explain E0207`.

2
tests/ui/nll/issue-50716.rs
View file

@ -5,7 +5,7 @@ trait A {
type X: ?Sized;
}
fn foo<'a, T: 'static>(s: Box<<&'a T as A>::X>)
fn foo<'a, T: 'static>(s: Box<<&'a T as A>::X>) //~ ERROR
where
for<'b> &'b T: A,
<&'static T as A>::X: Sized

18
tests/ui/nll/issue-50716.stderr
View file

@ -1,3 +1,18 @@
error[E0308]: mismatched types
--> $DIR/issue-50716.rs:8:27
|
LL | fn foo<'a, T: 'static>(s: Box<<&'a T as A>::X>)
| ^^^^^^^^^^^^^^^^^^^^ lifetime mismatch
|
= note: expected trait `<<&'a T as A>::X as MetaSized>`
found trait `<<&'static T as A>::X as MetaSized>`
note: the lifetime `'a` as defined here...
--> $DIR/issue-50716.rs:8:8
|
LL | fn foo<'a, T: 'static>(s: Box<<&'a T as A>::X>)
| ^^
= note: ...does not necessarily outlive the static lifetime
error: lifetime may not live long enough
--> $DIR/issue-50716.rs:13:14
|
@ -7,5 +22,6 @@ LL | fn foo<'a, T: 'static>(s: Box<<&'a T as A>::X>)
LL | let _x = *s;
| ^^ proving this value is `Sized` requires that `'a` must outlive `'static`
error: aborting due to 1 previous error
error: aborting due to 2 previous errors
For more information about this error, try `rustc --explain E0308`.

4
tests/ui/sized-hierarchy/incomplete-inference-issue-143992.current_sized_hierarchy.stderr → tests/ui/sized-hierarchy/incomplete-inference-issue-143992.current.stderr
View file

@ -1,5 +1,5 @@
error[E0308]: mismatched types
--> $DIR/incomplete-inference-issue-143992.rs:30:28
--> $DIR/incomplete-inference-issue-143992.rs:27:28
|
LL | let _x = T::Assoc::new(());
| ------------- ^^ expected `[u32; 1]`, found `()`
@ -7,7 +7,7 @@ LL | let _x = T::Assoc::new(());
| arguments to this function are incorrect
|
note: associated function defined here
--> $DIR/incomplete-inference-issue-143992.rs:21:8
--> $DIR/incomplete-inference-issue-143992.rs:18:8
|
LL | fn new(r: R) -> R {
| ^^^ ----

4
tests/ui/sized-hierarchy/incomplete-inference-issue-143992.next_sized_hierarchy.stderr → tests/ui/sized-hierarchy/incomplete-inference-issue-143992.next.stderr
View file

@ -1,5 +1,5 @@
error[E0308]: mismatched types
--> $DIR/incomplete-inference-issue-143992.rs:30:28
--> $DIR/incomplete-inference-issue-143992.rs:27:28
|
LL | let _x = T::Assoc::new(());
| ------------- ^^ expected `[u32; 1]`, found `()`
@ -7,7 +7,7 @@ LL | let _x = T::Assoc::new(());
| arguments to this function are incorrect
|
note: associated function defined here
--> $DIR/incomplete-inference-issue-143992.rs:21:8
--> $DIR/incomplete-inference-issue-143992.rs:18:8
|
LL | fn new(r: R) -> R {
| ^^^ ----

12
tests/ui/sized-hierarchy/incomplete-inference-issue-143992.rs
View file

@ -1,12 +1,9 @@
//@ compile-flags: --crate-type=lib
//@ revisions: current next current_sized_hierarchy next_sized_hierarchy
//@ revisions: current next
//@ ignore-compare-mode-next-solver (explicit revisions)
//@[current] check-pass
//@[next] check-pass
//@[current] check-fail
//@[next] check-fail
//@[next] compile-flags: -Znext-solver
//@[next_sized_hierarchy] compile-flags: -Znext-solver
#![cfg_attr(any(current_sized_hierarchy, next_sized_hierarchy), feature(sized_hierarchy))]
// Test that we avoid incomplete inference when normalizing. Without this,
// `Trait`'s implicit `MetaSized` supertrait requires proving `T::Assoc<_>: MetaSized`
@ -28,6 +25,5 @@ where
T::Assoc<[u32; 1]>: Clone,
{
let _x = T::Assoc::new(());
//[next_sized_hierarchy]~^ ERROR mismatched types
//[current_sized_hierarchy]~^^ ERROR mismatched types
//~^ ERROR: mismatched types
}

45
tests/ui/sized-hierarchy/overflow.current.stderr Normal file
View file

@ -0,0 +1,45 @@
error[E0275]: overflow evaluating the requirement `Element: MetaSized`
--> $DIR/overflow.rs:17:16
|
LL | struct Element(<Box<Box<Element>> as ParseTokens>::Output);
| ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
|
note: required for `Box<Element>` to implement `ParseTokens`
--> $DIR/overflow.rs:13:31
|
LL | impl<T: ParseTokens + ?Sized> ParseTokens for Box<T> {
| - ^^^^^^^^^^^ ^^^^^^
| |
| unsatisfied trait bound introduced here
= note: 1 redundant requirement hidden
= note: required for `Box<Box<Element>>` to implement `ParseTokens`
error[E0275]: overflow evaluating the requirement `Box<Element>: ParseTokens`
--> $DIR/overflow.rs:19:22
|
LL | impl ParseTokens for Element {
| ^^^^^^^
|
note: required for `Box<Box<Element>>` to implement `ParseTokens`
--> $DIR/overflow.rs:13:31
|
LL | impl<T: ParseTokens + ?Sized> ParseTokens for Box<T> {
| ----------- ^^^^^^^^^^^ ^^^^^^
| |
| unsatisfied trait bound introduced here
note: required because it appears within the type `Element`
--> $DIR/overflow.rs:17:8
|
LL | struct Element(<Box<Box<Element>> as ParseTokens>::Output);
| ^^^^^^^
note: required by a bound in `ParseTokens`
--> $DIR/overflow.rs:10:1
|
LL | / trait ParseTokens {
LL | | type Output;
LL | | }
| |_^ required by this bound in `ParseTokens`
error: aborting due to 2 previous errors
For more information about this error, try `rustc --explain E0275`.

7
tests/ui/sized-hierarchy/overflow.rs
View file

@ -1,13 +1,10 @@
//@ compile-flags: --crate-type=lib
//@ revisions: current next
//@ ignore-compare-mode-next-solver (explicit revisions)
//@[current] check-pass
//@[current] check-fail
//@[next] check-pass
//@[next] compile-flags: -Znext-solver
// FIXME(sized_hierarchy): this is expected to fail in the old solver when there
// isn't a temporary revert of the `sized_hierarchy` feature
use std::marker::PhantomData;
trait ParseTokens {
@ -18,6 +15,8 @@ impl<T: ParseTokens + ?Sized> ParseTokens for Box<T> {
}
struct Element(<Box<Box<Element>> as ParseTokens>::Output);
//[current]~^ ERROR: overflow
impl ParseTokens for Element {
//[current]~^ ERROR: overflow
type Output = ();
}

7
tests/ui/traits/next-solver/cycles/normalizes-to-is-not-productive.stderr
View file

@ -17,6 +17,13 @@ LL | impl<T: Bound, U> Trait<U> for T {
| ----- ^^^^^^^^ ^
| |
| unsatisfied trait bound introduced here
note: required by a bound in `Bound`
--> $DIR/normalizes-to-is-not-productive.rs:8:1
|
LL | / trait Bound {
LL | | fn method();
LL | | }
| |_^ required by this bound in `Bound`
error[E0277]: the trait bound `Foo: Bound` is not satisfied
--> $DIR/normalizes-to-is-not-productive.rs:47:19

19
tests/ui/traits/next-solver/normalize/normalize-param-env-2.stderr
View file

@ -19,6 +19,23 @@ error[E0275]: overflow evaluating the requirement `<() as A<T>>::Assoc: A<T>`
LL | Self::Assoc: A<T>,
| ^^^^
error[E0275]: overflow evaluating the requirement `<() as A<T>>::Assoc: MetaSized`
--> $DIR/normalize-param-env-2.rs:24:22
|
LL | Self::Assoc: A<T>,
| ^^^^
|
note: required by a bound in `A`
--> $DIR/normalize-param-env-2.rs:9:1
|
LL | / trait A<T> {
LL | | type Assoc;
LL | |
LL | | fn f()
... |
LL | | }
| |_^ required by this bound in `A`
error[E0275]: overflow evaluating the requirement `<() as A<T>>::Assoc well-formed`
--> $DIR/normalize-param-env-2.rs:24:22
|
@ -46,6 +63,6 @@ LL | where
LL | Self::Assoc: A<T>,
| ^^^^ required by this bound in `A::f`
error: aborting due to 5 previous errors
error: aborting due to 6 previous errors
For more information about this error, try `rustc --explain E0275`.

16
tests/ui/traits/next-solver/normalize/normalize-param-env-4.next.stderr
View file

@ -4,6 +4,20 @@ error[E0275]: overflow evaluating the requirement `<T as Trait>::Assoc: Trait`
LL | <T as Trait>::Assoc: Trait,
| ^^^^^
error: aborting due to 1 previous error
error[E0275]: overflow evaluating the requirement `<T as Trait>::Assoc: MetaSized`
--> $DIR/normalize-param-env-4.rs:19:26
|
LL | <T as Trait>::Assoc: Trait,
| ^^^^^
|
note: required by a bound in `Trait`
--> $DIR/normalize-param-env-4.rs:7:1
|
LL | / trait Trait {
LL | | type Assoc;
LL | | }
| |_^ required by this bound in `Trait`
error: aborting due to 2 previous errors
For more information about this error, try `rustc --explain E0275`.

1
tests/ui/traits/resolve-impl-before-constrain-check.rs
View file

@ -15,6 +15,7 @@ use foo::*;
fn test() -> impl Sized {
<() as Callable>::call()
//~^ ERROR type annotations needed
}
fn main() {}

11
tests/ui/traits/resolve-impl-before-constrain-check.stderr
View file

@ -4,6 +4,13 @@ error[E0207]: the type parameter `V` is not constrained by the impl trait, self
LL | impl<V: ?Sized> Callable for () {
| ^ unconstrained type parameter
error: aborting due to 1 previous error
error[E0282]: type annotations needed
--> $DIR/resolve-impl-before-constrain-check.rs:17:6
|
LL | <() as Callable>::call()
| ^^ cannot infer type for type parameter `V`
For more information about this error, try `rustc --explain E0207`.
error: aborting due to 2 previous errors
Some errors have detailed explanations: E0207, E0282.
For more information about an error, try `rustc --explain E0207`.