Auto merge of #102787 - Dylan-DPC:rollup-fvbb4t9, r=Dylan-DPC

Rollup of 6 pull requests

Successful merges:

 - #102300 (Use a macro to not have to copy-paste `ConstFnMutClosure::new(&mut fold, NeverShortCircuit::wrap_mut_2_imp)).0` everywhere)
 - #102475 (unsafe keyword: trait examples and unsafe_op_in_unsafe_fn update)
 - #102760 (Avoid repeated re-initialization of the BufReader buffer)
 - #102764 (Check `WhereClauseReferencesSelf` after all other object safety checks)
 - #102779 (Fix `type_of` ICE)
 - #102780 (run Miri CI when std::sys changes)

Failed merges:

r? `@ghost`
`@rustbot` modify labels: rollup
This commit is contained in:
bors 2022-10-07 17:37:39 +00:00
commit 2d3a85b4f8
20 changed files with 319 additions and 164 deletions

View File

@ -493,8 +493,10 @@ pub(super) fn type_of(tcx: TyCtxt<'_>, def_id: DefId) -> Ty<'_> {
},
def_id.to_def_id(),
);
if let Some(assoc_item) = assoc_item {
tcx.type_of(tcx.generics_of(assoc_item.def_id).params[idx].def_id)
if let Some(param)
= assoc_item.map(|item| &tcx.generics_of(item.def_id).params[idx]).filter(|param| param.kind.is_ty_or_const())
{
tcx.type_of(param.def_id)
} else {
// FIXME(associated_const_equality): add a useful error message here.
tcx.ty_error_with_message(

View File

@ -447,19 +447,6 @@ fn virtual_call_violation_for_method<'tcx>(
return Some(MethodViolationCode::Generic);
}
if tcx
.predicates_of(method.def_id)
.predicates
.iter()
// A trait object can't claim to live more than the concrete type,
// so outlives predicates will always hold.
.cloned()
.filter(|(p, _)| p.to_opt_type_outlives().is_none())
.any(|pred| contains_illegal_self_type_reference(tcx, trait_def_id, pred))
{
return Some(MethodViolationCode::WhereClauseReferencesSelf);
}
let receiver_ty = tcx.liberate_late_bound_regions(method.def_id, sig.input(0));
// Until `unsized_locals` is fully implemented, `self: Self` can't be dispatched on.
@ -538,6 +525,21 @@ fn virtual_call_violation_for_method<'tcx>(
}
}
// NOTE: This check happens last, because it results in a lint, and not a
// hard error.
if tcx
.predicates_of(method.def_id)
.predicates
.iter()
// A trait object can't claim to live more than the concrete type,
// so outlives predicates will always hold.
.cloned()
.filter(|(p, _)| p.to_opt_type_outlives().is_none())
.any(|pred| contains_illegal_self_type_reference(tcx, trait_def_id, pred))
{
return Some(MethodViolationCode::WhereClauseReferencesSelf);
}
None
}

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@ -1,7 +1,6 @@
use crate::array;
use crate::const_closure::ConstFnMutClosure;
use crate::iter::{ByRefSized, FusedIterator, Iterator};
use crate::ops::{ControlFlow, NeverShortCircuit, Try};
use crate::ops::{ControlFlow, Try};
/// An iterator over `N` elements of the iterator at a time.
///
@ -83,13 +82,7 @@ fn try_fold<B, F, R>(&mut self, init: B, mut f: F) -> R
}
}
fn fold<B, F>(mut self, init: B, mut f: F) -> B
where
Self: Sized,
F: FnMut(B, Self::Item) -> B,
{
self.try_fold(init, ConstFnMutClosure::new(&mut f, NeverShortCircuit::wrap_mut_2_imp)).0
}
impl_fold_via_try_fold! { fold -> try_fold }
}
#[unstable(feature = "iter_array_chunks", reason = "recently added", issue = "100450")]
@ -127,13 +120,7 @@ fn try_rfold<B, F, R>(&mut self, init: B, mut f: F) -> R
try { acc }
}
fn rfold<B, F>(mut self, init: B, mut f: F) -> B
where
Self: Sized,
F: FnMut(B, Self::Item) -> B,
{
self.try_rfold(init, ConstFnMutClosure::new(&mut f, NeverShortCircuit::wrap_mut_2_imp)).0
}
impl_fold_via_try_fold! { rfold -> try_rfold }
}
impl<I, const N: usize> ArrayChunks<I, N>

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@ -64,19 +64,7 @@ fn try_fold<Acc, Fold, R>(&mut self, init: Acc, mut fold: Fold) -> R
.into_try()
}
#[inline]
fn fold<Acc, Fold>(mut self, init: Acc, fold: Fold) -> Acc
where
Self: Sized,
Fold: FnMut(Acc, Self::Item) -> Acc,
{
#[inline]
fn ok<B, T>(mut f: impl FnMut(B, T) -> B) -> impl FnMut(B, T) -> Result<B, !> {
move |acc, x| Ok(f(acc, x))
}
self.try_fold(init, ok(fold)).unwrap()
}
impl_fold_via_try_fold! { fold -> try_fold }
}
#[unstable(issue = "none", feature = "inplace_iteration")]

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@ -1,6 +1,5 @@
use crate::const_closure::ConstFnMutClosure;
use crate::iter::{InPlaceIterable, Iterator};
use crate::ops::{ChangeOutputType, ControlFlow, FromResidual, NeverShortCircuit, Residual, Try};
use crate::ops::{ChangeOutputType, ControlFlow, FromResidual, Residual, Try};
mod array_chunks;
mod by_ref_sized;
@ -204,13 +203,7 @@ fn try_fold<B, F, T>(&mut self, init: B, mut f: F) -> T
.into_try()
}
fn fold<B, F>(mut self, init: B, mut fold: F) -> B
where
Self: Sized,
F: FnMut(B, Self::Item) -> B,
{
self.try_fold(init, ConstFnMutClosure::new(&mut fold, NeverShortCircuit::wrap_mut_2_imp)).0
}
impl_fold_via_try_fold! { fold -> try_fold }
}
#[unstable(issue = "none", feature = "inplace_iteration")]

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@ -74,19 +74,7 @@ fn scan<'a, T, St, B, Acc, R: Try<Output = Acc>>(
self.iter.try_fold(init, scan(state, f, fold)).into_try()
}
#[inline]
fn fold<Acc, Fold>(mut self, init: Acc, fold: Fold) -> Acc
where
Self: Sized,
Fold: FnMut(Acc, Self::Item) -> Acc,
{
#[inline]
fn ok<B, T>(mut f: impl FnMut(B, T) -> B) -> impl FnMut(B, T) -> Result<B, !> {
move |acc, x| Ok(f(acc, x))
}
self.try_fold(init, ok(fold)).unwrap()
}
impl_fold_via_try_fold! { fold -> try_fold }
}
#[unstable(issue = "none", feature = "inplace_iteration")]

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@ -206,17 +206,7 @@ fn check<T, Acc, R: Try<Output = Acc>>(
if n == 0 { try { init } } else { self.iter.try_rfold(init, check(n, fold)).into_try() }
}
fn rfold<Acc, Fold>(mut self, init: Acc, fold: Fold) -> Acc
where
Fold: FnMut(Acc, Self::Item) -> Acc,
{
#[inline]
fn ok<Acc, T>(mut f: impl FnMut(Acc, T) -> Acc) -> impl FnMut(Acc, T) -> Result<Acc, !> {
move |acc, x| Ok(f(acc, x))
}
self.try_rfold(init, ok(fold)).unwrap()
}
impl_fold_via_try_fold! { rfold -> try_rfold }
#[inline]
fn advance_back_by(&mut self, n: usize) -> Result<(), usize> {

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@ -98,19 +98,7 @@ fn check<'a, T, Acc, R: Try<Output = Acc>>(
}
}
#[inline]
fn fold<Acc, Fold>(mut self, init: Acc, fold: Fold) -> Acc
where
Self: Sized,
Fold: FnMut(Acc, Self::Item) -> Acc,
{
#[inline]
fn ok<B, T>(mut f: impl FnMut(B, T) -> B) -> impl FnMut(B, T) -> Result<B, !> {
move |acc, x| Ok(f(acc, x))
}
self.try_fold(init, ok(fold)).unwrap()
}
impl_fold_via_try_fold! { fold -> try_fold }
#[inline]
#[rustc_inherit_overflow_checks]

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@ -94,19 +94,7 @@ fn check<'a, T, Acc, R: Try<Output = Acc>>(
}
}
#[inline]
fn fold<Acc, Fold>(mut self, init: Acc, fold: Fold) -> Acc
where
Self: Sized,
Fold: FnMut(Acc, Self::Item) -> Acc,
{
#[inline]
fn ok<B, T>(mut f: impl FnMut(B, T) -> B) -> impl FnMut(B, T) -> Result<B, !> {
move |acc, x| Ok(f(acc, x))
}
self.try_fold(init, ok(fold)).unwrap()
}
impl_fold_via_try_fold! { fold -> try_fold }
}
#[stable(feature = "fused", since = "1.26.0")]

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@ -352,6 +352,29 @@
#![stable(feature = "rust1", since = "1.0.0")]
// This needs to be up here in order to be usable in the child modules
macro_rules! impl_fold_via_try_fold {
(fold -> try_fold) => {
impl_fold_via_try_fold! { @internal fold -> try_fold }
};
(rfold -> try_rfold) => {
impl_fold_via_try_fold! { @internal rfold -> try_rfold }
};
(@internal $fold:ident -> $try_fold:ident) => {
#[inline]
fn $fold<AAA, FFF>(mut self, init: AAA, mut fold: FFF) -> AAA
where
FFF: FnMut(AAA, Self::Item) -> AAA,
{
use crate::const_closure::ConstFnMutClosure;
use crate::ops::NeverShortCircuit;
let fold = ConstFnMutClosure::new(&mut fold, NeverShortCircuit::wrap_mut_2_imp);
self.$try_fold(init, fold).0
}
};
}
#[stable(feature = "rust1", since = "1.0.0")]
pub use self::traits::Iterator;

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@ -1150,19 +1150,7 @@ fn try_fold<B, F, R>(&mut self, init: B, f: F) -> R
self.spec_try_fold(init, f)
}
#[inline]
fn fold<B, F>(mut self, init: B, f: F) -> B
where
Self: Sized,
F: FnMut(B, Self::Item) -> B,
{
#[inline]
fn ok<B, T>(mut f: impl FnMut(B, T) -> B) -> impl FnMut(B, T) -> Result<B, !> {
move |acc, x| Ok(f(acc, x))
}
self.try_fold(init, ok(f)).unwrap()
}
impl_fold_via_try_fold! { fold -> try_fold }
#[inline]
fn last(mut self) -> Option<A> {
@ -1230,19 +1218,7 @@ fn try_rfold<B, F, R>(&mut self, init: B, f: F) -> R
self.spec_try_rfold(init, f)
}
#[inline]
fn rfold<B, F>(mut self, init: B, f: F) -> B
where
Self: Sized,
F: FnMut(B, Self::Item) -> B,
{
#[inline]
fn ok<B, T>(mut f: impl FnMut(B, T) -> B) -> impl FnMut(B, T) -> Result<B, !> {
move |acc, x| Ok(f(acc, x))
}
self.try_rfold(init, ok(f)).unwrap()
}
impl_fold_via_try_fold! { rfold -> try_rfold }
}
// Safety: See above implementation for `ops::Range<A>`

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@ -224,6 +224,14 @@ fn discard_buffer(&mut self) {
}
}
// This is only used by a test which asserts that the initialization-tracking is correct.
#[cfg(test)]
impl<R> BufReader<R> {
pub fn initialized(&self) -> usize {
self.buf.initialized()
}
}
impl<R: Seek> BufReader<R> {
/// Seeks relative to the current position. If the new position lies within the buffer,
/// the buffer will not be flushed, allowing for more efficient seeks.

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@ -20,13 +20,19 @@ pub struct Buffer {
// Each call to `fill_buf` sets `filled` to indicate how many bytes at the start of `buf` are
// initialized with bytes from a read.
filled: usize,
// This is the max number of bytes returned across all `fill_buf` calls. We track this so that we
// can accurately tell `read_buf` how many bytes of buf are initialized, to bypass as much of its
// defensive initialization as possible. Note that while this often the same as `filled`, it
// doesn't need to be. Calls to `fill_buf` are not required to actually fill the buffer, and
// omitting this is a huge perf regression for `Read` impls that do not.
initialized: usize,
}
impl Buffer {
#[inline]
pub fn with_capacity(capacity: usize) -> Self {
let buf = Box::new_uninit_slice(capacity);
Self { buf, pos: 0, filled: 0 }
Self { buf, pos: 0, filled: 0, initialized: 0 }
}
#[inline]
@ -51,6 +57,12 @@ pub fn pos(&self) -> usize {
self.pos
}
// This is only used by a test which asserts that the initialization-tracking is correct.
#[cfg(test)]
pub fn initialized(&self) -> usize {
self.initialized
}
#[inline]
pub fn discard_buffer(&mut self) {
self.pos = 0;
@ -96,13 +108,14 @@ pub fn fill_buf(&mut self, mut reader: impl Read) -> io::Result<&[u8]> {
let mut buf = BorrowedBuf::from(&mut *self.buf);
// SAFETY: `self.filled` bytes will always have been initialized.
unsafe {
buf.set_init(self.filled);
buf.set_init(self.initialized);
}
reader.read_buf(buf.unfilled())?;
self.filled = buf.len();
self.pos = 0;
self.filled = buf.len();
self.initialized = buf.init_len();
}
Ok(self.buffer())
}

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@ -1039,3 +1039,27 @@ fn single_formatted_write() {
writeln!(&mut writer, "{}, {}!", "hello", "world").unwrap();
assert_eq!(writer.get_ref().events, [RecordedEvent::Write("hello, world!\n".to_string())]);
}
#[test]
fn bufreader_full_initialize() {
struct OneByteReader;
impl Read for OneByteReader {
fn read(&mut self, buf: &mut [u8]) -> crate::io::Result<usize> {
if buf.len() > 0 {
buf[0] = 0;
Ok(1)
} else {
Ok(0)
}
}
}
let mut reader = BufReader::new(OneByteReader);
// Nothing is initialized yet.
assert_eq!(reader.initialized(), 0);
let buf = reader.fill_buf().unwrap();
// We read one byte...
assert_eq!(buf.len(), 1);
// But we initialized the whole buffer!
assert_eq!(reader.initialized(), reader.capacity());
}

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@ -1867,11 +1867,15 @@ mod type_keyword {}
/// Code or interfaces whose [memory safety] cannot be verified by the type
/// system.
///
/// The `unsafe` keyword has two uses: to declare the existence of contracts the
/// compiler can't check (`unsafe fn` and `unsafe trait`), and to declare that a
/// programmer has checked that these contracts have been upheld (`unsafe {}`
/// and `unsafe impl`, but also `unsafe fn` -- see below). They are not mutually
/// exclusive, as can be seen in `unsafe fn`.
/// The `unsafe` keyword has two uses:
/// - to declare the existence of contracts the compiler can't check (`unsafe fn` and `unsafe
/// trait`),
/// - and to declare that a programmer has checked that these contracts have been upheld (`unsafe
/// {}` and `unsafe impl`, but also `unsafe fn` -- see below).
///
/// They are not mutually exclusive, as can be seen in `unsafe fn`: the body of an `unsafe fn` is,
/// by default, treated like an unsafe block. The `unsafe_op_in_unsafe_fn` lint can be enabled to
/// change that.
///
/// # Unsafe abilities
///
@ -1914,12 +1918,12 @@ mod type_keyword {}
/// - `unsafe impl`: the contract necessary to implement the trait has been
/// checked by the programmer and is guaranteed to be respected.
///
/// `unsafe fn` also acts like an `unsafe {}` block
/// By default, `unsafe fn` also acts like an `unsafe {}` block
/// around the code inside the function. This means it is not just a signal to
/// the caller, but also promises that the preconditions for the operations
/// inside the function are upheld. Mixing these two meanings can be confusing
/// and [proposal]s exist to use `unsafe {}` blocks inside such functions when
/// making `unsafe` operations.
/// inside the function are upheld. Mixing these two meanings can be confusing, so the
/// `unsafe_op_in_unsafe_fn` lint can be enabled to warn against that and require explicit unsafe
/// blocks even inside `unsafe fn`.
///
/// See the [Rustnomicon] and the [Reference] for more information.
///
@ -1987,13 +1991,16 @@ mod type_keyword {}
///
/// ```rust
/// # #![allow(dead_code)]
/// #![deny(unsafe_op_in_unsafe_fn)]
///
/// /// Dereference the given pointer.
/// ///
/// /// # Safety
/// ///
/// /// `ptr` must be aligned and must not be dangling.
/// unsafe fn deref_unchecked(ptr: *const i32) -> i32 {
/// *ptr
/// // SAFETY: the caller is required to ensure that `ptr` is aligned and dereferenceable.
/// unsafe { *ptr }
/// }
///
/// let a = 3;
@ -2003,35 +2010,118 @@ mod type_keyword {}
/// unsafe { assert_eq!(*b, deref_unchecked(b)); };
/// ```
///
/// Traits marked as `unsafe` must be [`impl`]emented using `unsafe impl`. This
/// makes a guarantee to other `unsafe` code that the implementation satisfies
/// the trait's safety contract. The [Send] and [Sync] traits are examples of
/// this behaviour in the standard library.
/// ## `unsafe` and traits
///
/// The interactions of `unsafe` and traits can be surprising, so let us contrast the
/// two combinations of safe `fn` in `unsafe trait` and `unsafe fn` in safe trait using two
/// examples:
///
/// ```rust
/// /// Implementors of this trait must guarantee an element is always
/// /// accessible with index 3.
/// unsafe trait ThreeIndexable<T> {
/// /// Returns a reference to the element with index 3 in `&self`.
/// fn three(&self) -> &T;
/// /// # Safety
/// ///
/// /// `make_even` must return an even number.
/// unsafe trait MakeEven {
/// fn make_even(&self) -> i32;
/// }
///
/// // The implementation of `ThreeIndexable` for `[T; 4]` is `unsafe`
/// // because the implementor must abide by a contract the compiler cannot
/// // check but as a programmer we know there will always be a valid element
/// // at index 3 to access.
/// unsafe impl<T> ThreeIndexable<T> for [T; 4] {
/// fn three(&self) -> &T {
/// // SAFETY: implementing the trait means there always is an element
/// // with index 3 accessible.
/// unsafe { self.get_unchecked(3) }
/// // SAFETY: Our `make_even` always returns something even.
/// unsafe impl MakeEven for i32 {
/// fn make_even(&self) -> i32 {
/// self << 1
/// }
/// }
///
/// let a = [1, 2, 4, 8];
/// assert_eq!(a.three(), &8);
/// fn use_make_even(x: impl MakeEven) {
/// if x.make_even() % 2 == 1 {
/// // SAFETY: this can never happen, because all `MakeEven` implementations
/// // ensure that `make_even` returns something even.
/// unsafe { std::hint::unreachable_unchecked() };
/// }
/// }
/// ```
///
/// Note how the safety contract of the trait is upheld by the implementation, and is itself used to
/// uphold the safety contract of the unsafe function `unreachable_unchecked` called by
/// `use_make_even`. `make_even` itself is a safe function because its *callers* do not have to
/// worry about any contract, only the *implementation* of `MakeEven` is required to uphold a
/// certain contract. `use_make_even` is safe because it can use the promise made by `MakeEven`
/// implementations to uphold the safety contract of the `unsafe fn unreachable_unchecked` it calls.
///
/// It is also possible to have `unsafe fn` in a regular safe `trait`:
///
/// ```rust
/// # #![feature(never_type)]
/// #![deny(unsafe_op_in_unsafe_fn)]
///
/// trait Indexable {
/// const LEN: usize;
///
/// /// # Safety
/// ///
/// /// The caller must ensure that `idx < LEN`.
/// unsafe fn idx_unchecked(&self, idx: usize) -> i32;
/// }
///
/// // The implementation for `i32` doesn't need to do any contract reasoning.
/// impl Indexable for i32 {
/// const LEN: usize = 1;
///
/// unsafe fn idx_unchecked(&self, idx: usize) -> i32 {
/// debug_assert_eq!(idx, 0);
/// *self
/// }
/// }
///
/// // The implementation for arrays exploits the function contract to
/// // make use of `get_unchecked` on slices and avoid a run-time check.
/// impl Indexable for [i32; 42] {
/// const LEN: usize = 42;
///
/// unsafe fn idx_unchecked(&self, idx: usize) -> i32 {
/// // SAFETY: As per this trait's documentation, the caller ensures
/// // that `idx < 42`.
/// unsafe { *self.get_unchecked(idx) }
/// }
/// }
///
/// // The implementation for the never type declares a length of 0,
/// // which means `idx_unchecked` can never be called.
/// impl Indexable for ! {
/// const LEN: usize = 0;
///
/// unsafe fn idx_unchecked(&self, idx: usize) -> i32 {
/// // SAFETY: As per this trait's documentation, the caller ensures
/// // that `idx < 0`, which is impossible, so this is dead code.
/// unsafe { std::hint::unreachable_unchecked() }
/// }
/// }
///
/// fn use_indexable<I: Indexable>(x: I, idx: usize) -> i32 {
/// if idx < I::LEN {
/// // SAFETY: We have checked that `idx < I::LEN`.
/// unsafe { x.idx_unchecked(idx) }
/// } else {
/// panic!("index out-of-bounds")
/// }
/// }
/// ```
///
/// This time, `use_indexable` is safe because it uses a run-time check to discharge the safety
/// contract of `idx_unchecked`. Implementing `Indexable` is safe because when writing
/// `idx_unchecked`, we don't have to worry: our *callers* need to discharge a proof obligation
/// (like `use_indexable` does), but the *implementation* of `get_unchecked` has no proof obligation
/// to contend with. Of course, the implementation of `Indexable` may choose to call other unsafe
/// operations, and then it needs an `unsafe` *block* to indicate it discharged the proof
/// obligations of its callees. (We enabled `unsafe_op_in_unsafe_fn`, so the body of `idx_unchecked`
/// is not implicitly an unsafe block.) For that purpose it can make use of the contract that all
/// its callers must uphold -- the fact that `idx < LEN`.
///
/// Formally speaking, an `unsafe fn` in a trait is a function with *preconditions* that go beyond
/// those encoded by the argument types (such as `idx < LEN`), whereas an `unsafe trait` can declare
/// that some of its functions have *postconditions* that go beyond those encoded in the return type
/// (such as returning an even integer). If a trait needs a function with both extra precondition
/// and extra postcondition, then it needs an `unsafe fn` in an `unsafe trait`.
///
/// [`extern`]: keyword.extern.html
/// [`trait`]: keyword.trait.html
/// [`static`]: keyword.static.html
@ -2043,7 +2133,6 @@ mod type_keyword {}
/// [nomicon-soundness]: ../nomicon/safe-unsafe-meaning.html
/// [soundness]: https://rust-lang.github.io/unsafe-code-guidelines/glossary.html#soundness-of-code--of-a-library
/// [Reference]: ../reference/unsafety.html
/// [proposal]: https://github.com/rust-lang/rfcs/pull/2585
/// [discussion on Rust Internals]: https://internals.rust-lang.org/t/what-does-unsafe-mean/6696
mod unsafe_keyword {}

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@ -19,9 +19,12 @@ if [[ -n "${CI_ONLY_WHEN_SUBMODULES_CHANGED-}" ]]; then
# those files are present in the diff a submodule was updated.
echo "Submodules were updated"
elif ! (git diff --quiet "$BASE_COMMIT" -- \
src/tools/clippy src/tools/rustfmt src/tools/miri); then
src/tools/clippy src/tools/rustfmt src/tools/miri
library/std/src/sys); then
# There is not an easy blanket search for subtrees. For now, manually list
# the subtrees.
# Also run this when the platform-specific parts of std change, in case
# that breaks Miri.
echo "Tool subtrees were updated"
elif ! (git diff --quiet "$BASE_COMMIT" -- \
src/test/rustdoc-gui \

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@ -0,0 +1,14 @@
#![feature(generic_const_exprs)]
#![allow(incomplete_features)]
trait X {
type Y<'a>;
}
const _: () = {
fn f2<'a>(arg: Box<dyn X<Y<1> = &'a ()>>) {}
//~^ ERROR this associated type takes 1 lifetime argument but 0 lifetime arguments
//~| ERROR this associated type takes 0 generic arguments but 1 generic argument
};
fn main() {}

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@ -0,0 +1,33 @@
error[E0107]: this associated type takes 1 lifetime argument but 0 lifetime arguments were supplied
--> $DIR/issue-102768.rs:9:30
|
LL | fn f2<'a>(arg: Box<dyn X<Y<1> = &'a ()>>) {}
| ^ expected 1 lifetime argument
|
note: associated type defined here, with 1 lifetime parameter: `'a`
--> $DIR/issue-102768.rs:5:10
|
LL | type Y<'a>;
| ^ --
help: add missing lifetime argument
|
LL | fn f2<'a>(arg: Box<dyn X<Y<'a, 1> = &'a ()>>) {}
| +++
error[E0107]: this associated type takes 0 generic arguments but 1 generic argument was supplied
--> $DIR/issue-102768.rs:9:30
|
LL | fn f2<'a>(arg: Box<dyn X<Y<1> = &'a ()>>) {}
| ^--- help: remove these generics
| |
| expected 0 generic arguments
|
note: associated type defined here, with 0 generic parameters
--> $DIR/issue-102768.rs:5:10
|
LL | type Y<'a>;
| ^
error: aborting due to 2 previous errors
For more information about this error, try `rustc --explain E0107`.

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@ -0,0 +1,26 @@
// compile-flags: --crate-type=lib
// This test checks that the `where_clauses_object_safety` lint does not cause
// other object safety *hard errors* to be suppressed, because we currently
// only emit one object safety error per trait...
use std::future::Future;
use std::pin::Pin;
pub trait Fetcher: Send + Sync {
fn get<'a>(self: &'a Box<Self>) -> Pin<Box<dyn Future<Output = Vec<u8>> + 'a>>
where
Self: Sync,
{
todo!()
}
}
fn fetcher() -> Box<dyn Fetcher> {
//~^ ERROR the trait `Fetcher` cannot be made into an object
todo!()
}
pub fn foo() {
let fetcher = fetcher();
let _ = fetcher.get();
}

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error[E0038]: the trait `Fetcher` cannot be made into an object
--> $DIR/issue-102762.rs:18:21
|
LL | fn get<'a>(self: &'a Box<Self>) -> Pin<Box<dyn Future<Output = Vec<u8>> + 'a>>
| ------------- help: consider changing method `get`'s `self` parameter to be `&self`: `&Self`
...
LL | fn fetcher() -> Box<dyn Fetcher> {
| ^^^^^^^^^^^ `Fetcher` cannot be made into an object
|
note: for a trait to be "object safe" it needs to allow building a vtable to allow the call to be resolvable dynamically; for more information visit <https://doc.rust-lang.org/reference/items/traits.html#object-safety>
--> $DIR/issue-102762.rs:10:22
|
LL | pub trait Fetcher: Send + Sync {
| ------- this trait cannot be made into an object...
LL | fn get<'a>(self: &'a Box<Self>) -> Pin<Box<dyn Future<Output = Vec<u8>> + 'a>>
| ^^^^^^^^^^^^^ ...because method `get`'s `self` parameter cannot be dispatched on
error: aborting due to previous error
For more information about this error, try `rustc --explain E0038`.