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Auto merge of #105918 - matthiaskrgr:rollup-mmazd62, r=matthiaskrgr
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Rollup of 7 pull requests

Successful merges:

 - #105801 (Realistic `Path::as_mut_os_str` doctest)
 - #105860 (Add long error docs for `E0460` and `E0457`)
 - #105895 (Test that we don't add a new kind of breaking change with TAITs)
 - #105902 (docs: improve pin docs)
 - #105910 (Update books)
 - #105913 (rustdoc: remove width-limiter from source pages, stop overriding CSS)
 - #105915 (Revert "Replace usage of `ResumeTy` in async lowering with `Context`")

Failed merges:

r? `@ghost`
`@rustbot` modify labels: rollup
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bors committed Dec 20, 2022
2 parents 696563e + 575b2a2 commit c43bc13
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Showing 36 changed files with 250 additions and 85 deletions.
57 changes: 21 additions & 36 deletions compiler/rustc_ast_lowering/src/expr.rs
Original file line number Diff line number Diff line change
Expand Up @@ -16,7 +16,7 @@ use rustc_hir::def::Res;
use rustc_hir::definitions::DefPathData;
use rustc_session::errors::report_lit_error;
use rustc_span::source_map::{respan, DesugaringKind, Span, Spanned};
use rustc_span::symbol::{kw, sym, Ident};
use rustc_span::symbol::{sym, Ident};
use rustc_span::DUMMY_SP;
use thin_vec::thin_vec;

Expand Down Expand Up @@ -596,38 +596,14 @@ impl<'hir> LoweringContext<'_, 'hir> {
) -> hir::ExprKind<'hir> {
let output = ret_ty.unwrap_or_else(|| hir::FnRetTy::DefaultReturn(self.lower_span(span)));

// Resume argument type, which should be `&mut Context<'_>`.
// NOTE: Using the `'static` lifetime here is technically cheating.
// The `Future::poll` argument really is `&'a mut Context<'b>`, but we cannot
// express the fact that we are not storing it across yield-points yet,
// and we would thus run into lifetime errors.
// See <https://github.com/rust-lang/rust/issues/68923>.
// Our lowering makes sure we are not mis-using the `_task_context` input type
// in the sense that we are indeed not using it across yield points. We
// get a fresh `&mut Context` for each resume / call of `Future::poll`.
// This "cheating" was previously done with a `ResumeTy` that contained a raw
// pointer, and a `get_context` accessor that pulled the `Context` lifetimes
// out of thin air.
let context_lifetime_ident = Ident::with_dummy_span(kw::StaticLifetime);
let context_lifetime = self.arena.alloc(hir::Lifetime {
hir_id: self.next_id(),
ident: context_lifetime_ident,
res: hir::LifetimeName::Static,
});
let context_path =
hir::QPath::LangItem(hir::LangItem::Context, self.lower_span(span), None);
let context_ty = hir::MutTy {
ty: self.arena.alloc(hir::Ty {
hir_id: self.next_id(),
kind: hir::TyKind::Path(context_path),
span: self.lower_span(span),
}),
mutbl: hir::Mutability::Mut,
};
// Resume argument type: `ResumeTy`
let unstable_span =
self.mark_span_with_reason(DesugaringKind::Async, span, self.allow_gen_future.clone());
let resume_ty = hir::QPath::LangItem(hir::LangItem::ResumeTy, unstable_span, None);
let input_ty = hir::Ty {
hir_id: self.next_id(),
kind: hir::TyKind::Rptr(context_lifetime, context_ty),
span: self.lower_span(span),
kind: hir::TyKind::Path(resume_ty),
span: unstable_span,
};

// The closure/generator `FnDecl` takes a single (resume) argument of type `input_ty`.
Expand Down Expand Up @@ -686,9 +662,12 @@ impl<'hir> LoweringContext<'_, 'hir> {
.map_or(false, |attrs| attrs.into_iter().any(|attr| attr.has_name(sym::track_caller)));

let hir_id = self.lower_node_id(closure_node_id);
let unstable_span =
self.mark_span_with_reason(DesugaringKind::Async, span, self.allow_gen_future.clone());
if track_caller {
let unstable_span = self.mark_span_with_reason(
DesugaringKind::Async,
span,
self.allow_gen_future.clone(),
);
self.lower_attrs(
hir_id,
&[Attribute {
Expand Down Expand Up @@ -731,7 +710,7 @@ impl<'hir> LoweringContext<'_, 'hir> {
/// mut __awaitee => loop {
/// match unsafe { ::std::future::Future::poll(
/// <::std::pin::Pin>::new_unchecked(&mut __awaitee),
/// task_context,
/// ::std::future::get_context(task_context),
/// ) } {
/// ::std::task::Poll::Ready(result) => break result,
/// ::std::task::Poll::Pending => {}
Expand Down Expand Up @@ -772,7 +751,7 @@ impl<'hir> LoweringContext<'_, 'hir> {
// unsafe {
// ::std::future::Future::poll(
// ::std::pin::Pin::new_unchecked(&mut __awaitee),
// task_context,
// ::std::future::get_context(task_context),
// )
// }
let poll_expr = {
Expand All @@ -790,10 +769,16 @@ impl<'hir> LoweringContext<'_, 'hir> {
arena_vec![self; ref_mut_awaitee],
Some(expr_hir_id),
);
let get_context = self.expr_call_lang_item_fn_mut(
gen_future_span,
hir::LangItem::GetContext,
arena_vec![self; task_context],
Some(expr_hir_id),
);
let call = self.expr_call_lang_item_fn(
span,
hir::LangItem::FuturePoll,
arena_vec![self; new_unchecked, task_context],
arena_vec![self; new_unchecked, get_context],
Some(expr_hir_id),
);
self.arena.alloc(self.expr_unsafe(call))
Expand Down
4 changes: 2 additions & 2 deletions compiler/rustc_error_codes/src/error_codes.rs
Original file line number Diff line number Diff line change
Expand Up @@ -239,8 +239,10 @@ E0452: include_str!("./error_codes/E0452.md"),
E0453: include_str!("./error_codes/E0453.md"),
E0454: include_str!("./error_codes/E0454.md"),
E0455: include_str!("./error_codes/E0455.md"),
E0457: include_str!("./error_codes/E0457.md"),
E0458: include_str!("./error_codes/E0458.md"),
E0459: include_str!("./error_codes/E0459.md"),
E0460: include_str!("./error_codes/E0460.md"),
E0463: include_str!("./error_codes/E0463.md"),
E0464: include_str!("./error_codes/E0464.md"),
E0466: include_str!("./error_codes/E0466.md"),
Expand Down Expand Up @@ -592,8 +594,6 @@ E0791: include_str!("./error_codes/E0791.md"),
// E0421, // merged into 531
// E0427, // merged into 530
// E0456, // plugin `..` is not available for triple `..`
E0457, // plugin `..` only found in rlib format, but must be available...
E0460, // found possibly newer version of crate `..`
E0461, // couldn't find crate `..` with expected target triple ..
E0462, // found staticlib `..` instead of rlib or dylib
E0465, // multiple .. candidates for `..` found
Expand Down
36 changes: 36 additions & 0 deletions compiler/rustc_error_codes/src/error_codes/E0457.md
Original file line number Diff line number Diff line change
@@ -0,0 +1,36 @@
Plugin `..` only found in rlib format, but must be available in dylib format.

Erroronous code example:

`rlib-plugin.rs`
```ignore (needs-linkage-with-other-tests)
#![crate_type = "rlib"]
#![feature(rustc_private)]
extern crate rustc_middle;
extern crate rustc_driver;
use rustc_driver::plugin::Registry;
#[no_mangle]
fn __rustc_plugin_registrar(_: &mut Registry) {}
```

`main.rs`
```ignore (needs-linkage-with-other-tests)
#![feature(plugin)]
#![plugin(rlib_plugin)] // error: plugin `rlib_plugin` only found in rlib
// format, but must be available in dylib
fn main() {}
```

The compiler exposes a plugin interface to allow altering the compile process
(adding lints, etc). Plugins must be defined in their own crates (similar to
[proc-macro](../reference/procedural-macros.html) isolation) and then compiled
and linked to another crate. Plugin crates *must* be compiled to the
dynamically-linked dylib format, and not the statically-linked rlib format.
Learn more about different output types in
[this section](../reference/linkage.html) of the Rust reference.

This error is easily fixed by recompiling the plugin crate in the dylib format.
71 changes: 71 additions & 0 deletions compiler/rustc_error_codes/src/error_codes/E0460.md
Original file line number Diff line number Diff line change
@@ -0,0 +1,71 @@
Found possibly newer version of crate `..` which `..` depends on.

Consider these erroneous files:

`a1.rs`
```ignore (needs-linkage-with-other-tests)
#![crate_name = "a"]
pub fn foo<T>() {}
```

`a2.rs`
```ignore (needs-linkage-with-other-tests)
#![crate_name = "a"]
pub fn foo<T>() {
println!("foo<T>()");
}
```

`b.rs`
```ignore (needs-linkage-with-other-tests)
#![crate_name = "b"]
extern crate a; // linked with `a1.rs`
pub fn foo() {
a::foo::<isize>();
}
```

`main.rs`
```ignore (needs-linkage-with-other-tests)
extern crate a; // linked with `a2.rs`
extern crate b; // error: found possibly newer version of crate `a` which `b`
// depends on
fn main() {}
```

The dependency graph of this program can be represented as follows:
```text
crate `main`
|
+-------------+
| |
| v
depends: | crate `b`
`a` v1 | |
| | depends:
| | `a` v2
v |
crate `a` <------+
```

Crate `main` depends on crate `a` (version 1) and crate `b` which in turn
depends on crate `a` (version 2); this discrepancy in versions cannot be
reconciled. This difference in versions typically occurs when one crate is
compiled and linked, then updated and linked to another crate. The crate
"version" is a SVH (Strict Version Hash) of the crate in an
implementation-specific way. Note that this error can *only* occur when
directly compiling and linking with `rustc`; [Cargo] automatically resolves
dependencies, without using the compiler's own dependency management that
causes this issue.

This error can be fixed by:
* Using [Cargo], the Rust package manager, automatically fixing this issue.
* Recompiling crate `a` so that both crate `b` and `main` have a uniform
version to depend on.

[Cargo]: ../cargo/index.html
3 changes: 2 additions & 1 deletion compiler/rustc_hir/src/lang_items.rs
Original file line number Diff line number Diff line change
Expand Up @@ -286,9 +286,10 @@ language_item_table! {

// FIXME(swatinem): the following lang items are used for async lowering and
// should become obsolete eventually.
ResumeTy, sym::ResumeTy, resume_ty, Target::Struct, GenericRequirement::None;
IdentityFuture, sym::identity_future, identity_future_fn, Target::Fn, GenericRequirement::None;
GetContext, sym::get_context, get_context_fn, Target::Fn, GenericRequirement::None;

Context, sym::Context, context, Target::Struct, GenericRequirement::None;
FuturePoll, sym::poll, future_poll_fn, Target::Method(MethodKind::Trait { body: false }), GenericRequirement::None;

FromFrom, sym::from, from_fn, Target::Method(MethodKind::Trait { body: false }), GenericRequirement::None;
Expand Down
3 changes: 2 additions & 1 deletion compiler/rustc_span/src/symbol.rs
Original file line number Diff line number Diff line change
Expand Up @@ -164,7 +164,6 @@ symbols! {
Capture,
Center,
Clone,
Context,
Continue,
Copy,
Count,
Expand Down Expand Up @@ -264,6 +263,7 @@ symbols! {
Relaxed,
Release,
Result,
ResumeTy,
Return,
Right,
Rust,
Expand Down Expand Up @@ -753,6 +753,7 @@ symbols! {
generic_associated_types_extended,
generic_const_exprs,
generic_param_attrs,
get_context,
global_allocator,
global_asm,
globs,
Expand Down
10 changes: 2 additions & 8 deletions library/core/src/future/mod.rs
Original file line number Diff line number Diff line change
Expand Up @@ -44,7 +44,7 @@ pub use poll_fn::{poll_fn, PollFn};
/// non-Send/Sync as well, and we don't want that.
///
/// It also simplifies the HIR lowering of `.await`.
// FIXME(swatinem): This type can be removed when bumping the bootstrap compiler
#[cfg_attr(not(bootstrap), lang = "ResumeTy")]
#[doc(hidden)]
#[unstable(feature = "gen_future", issue = "50547")]
#[derive(Debug, Copy, Clone)]
Expand All @@ -61,7 +61,6 @@ unsafe impl Sync for ResumeTy {}
/// This function returns a `GenFuture` underneath, but hides it in `impl Trait` to give
/// better error messages (`impl Future` rather than `GenFuture<[closure.....]>`).
// This is `const` to avoid extra errors after we recover from `const async fn`
// FIXME(swatinem): This fn can be removed when bumping the bootstrap compiler
#[cfg_attr(bootstrap, lang = "from_generator")]
#[doc(hidden)]
#[unstable(feature = "gen_future", issue = "50547")]
Expand Down Expand Up @@ -103,8 +102,7 @@ where
GenFuture(gen)
}

// FIXME(swatinem): This fn can be removed when bumping the bootstrap compiler
#[cfg_attr(bootstrap, lang = "get_context")]
#[lang = "get_context"]
#[doc(hidden)]
#[unstable(feature = "gen_future", issue = "50547")]
#[must_use]
Expand All @@ -115,10 +113,6 @@ pub unsafe fn get_context<'a, 'b>(cx: ResumeTy) -> &'a mut Context<'b> {
unsafe { &mut *cx.0.as_ptr().cast() }
}

// FIXME(swatinem): This fn is currently needed to work around shortcomings
// in type and lifetime inference.
// See the comment at the bottom of `LoweringContext::make_async_expr` and
// <https://github.com/rust-lang/rust/issues/104826>.
#[cfg_attr(not(bootstrap), lang = "identity_future")]
#[doc(hidden)]
#[unstable(feature = "gen_future", issue = "50547")]
Expand Down
36 changes: 35 additions & 1 deletion library/core/src/pin.rs
Original file line number Diff line number Diff line change
Expand Up @@ -485,6 +485,16 @@ impl<P: Deref<Target: Unpin>> Pin<P> {
///
/// Unlike `Pin::new_unchecked`, this method is safe because the pointer
/// `P` dereferences to an [`Unpin`] type, which cancels the pinning guarantees.
///
/// # Examples
///
/// ```
/// use std::pin::Pin;
///
/// let mut val: u8 = 5;
/// // We can pin the value, since it doesn't care about being moved
/// let mut pinned: Pin<&mut u8> = Pin::new(&mut val);
/// ```
#[inline(always)]
#[rustc_const_unstable(feature = "const_pin", issue = "76654")]
#[stable(feature = "pin", since = "1.33.0")]
Expand All @@ -496,8 +506,20 @@ impl<P: Deref<Target: Unpin>> Pin<P> {

/// Unwraps this `Pin<P>` returning the underlying pointer.
///
/// This requires that the data inside this `Pin` is [`Unpin`] so that we
/// This requires that the data inside this `Pin` implements [`Unpin`] so that we
/// can ignore the pinning invariants when unwrapping it.
///
/// # Examples
///
/// ```
/// use std::pin::Pin;
///
/// let mut val: u8 = 5;
/// let pinned: Pin<&mut u8> = Pin::new(&mut val);
/// // Unwrap the pin to get a reference to the value
/// let r = Pin::into_inner(pinned);
/// assert_eq!(*r, 5);
/// ```
#[inline(always)]
#[rustc_const_unstable(feature = "const_pin", issue = "76654")]
#[stable(feature = "pin_into_inner", since = "1.39.0")]
Expand Down Expand Up @@ -707,6 +729,18 @@ impl<P: DerefMut> Pin<P> {
///
/// This overwrites pinned data, but that is okay: its destructor gets
/// run before being overwritten, so no pinning guarantee is violated.
///
/// # Example
///
/// ```
/// use std::pin::Pin;
///
/// let mut val: u8 = 5;
/// let mut pinned: Pin<&mut u8> = Pin::new(&mut val);
/// println!("{}", pinned); // 5
/// pinned.as_mut().set(10);
/// println!("{}", pinned); // 10
/// ```
#[stable(feature = "pin", since = "1.33.0")]
#[inline(always)]
pub fn set(&mut self, value: P::Target)
Expand Down
1 change: 0 additions & 1 deletion library/core/src/task/wake.rs
Original file line number Diff line number Diff line change
Expand Up @@ -174,7 +174,6 @@ impl RawWakerVTable {
/// Currently, `Context` only serves to provide access to a [`&Waker`](Waker)
/// which can be used to wake the current task.
#[stable(feature = "futures_api", since = "1.36.0")]
#[cfg_attr(not(bootstrap), lang = "Context")]
pub struct Context<'a> {
waker: &'a Waker,
// Ensure we future-proof against variance changes by forcing
Expand Down
6 changes: 3 additions & 3 deletions library/std/src/path.rs
Original file line number Diff line number Diff line change
Expand Up @@ -2039,12 +2039,12 @@ impl Path {
/// #![feature(path_as_mut_os_str)]
/// use std::path::{Path, PathBuf};
///
/// let mut path = PathBuf::from("/Foo.TXT").into_boxed_path();
/// let mut path = PathBuf::from("Foo.TXT");
///
/// assert_ne!(&*path, Path::new("/foo.txt"));
/// assert_ne!(path, Path::new("foo.txt"));
///
/// path.as_mut_os_str().make_ascii_lowercase();
/// assert_eq!(&*path, Path::new("/foo.txt"));
/// assert_eq!(path, Path::new("foo.txt"));
/// ```
#[unstable(feature = "path_as_mut_os_str", issue = "105021")]
#[must_use]
Expand Down
2 changes: 1 addition & 1 deletion src/doc/nomicon
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