Rollup of 6 pull requests
Successful merges:
- #93901 (Stabilize native library modifier syntax and the `whole-archive` modifier specifically)
- #94806 (Fix `cargo run tidy`)
- #94869 (Add the generic_associated_types_extended feature)
- #95011 (async: Give predictable name to binding generated from .await expressions.)
- #95251 (Reduce max hash in raw strings from u16 to u8)
- #95298 (Fix double drop of allocator in IntoIter impl of Vec)
Failed merges:
r? `@ghost`
`@rustbot` modify labels: rollup
Fix double drop of allocator in IntoIter impl of Vec
Fixes#95269
The `drop` impl of `IntoIter` reconstructs a `RawVec` from `buf`, `cap` and `alloc`, when that `RawVec` is dropped it also drops the allocator. To avoid dropping the allocator twice we wrap it in `ManuallyDrop` in the `InttoIter` struct.
Note this is my first contribution to the standard library, so I might be missing some details or a better way to solve this.
async: Give predictable name to binding generated from .await expressions.
This name makes it to debuginfo and allows debuggers to identify such bindings and their captured versions in suspended async fns.
This will be useful for async stack traces, as discussed in https://internals.rust-lang.org/t/async-debugging-logical-stack-traces-setting-goals-collecting-examples/15547.
I don't know if this needs some discussion by ````@rust-lang/compiler,```` e.g. about the name of the binding (`__awaitee`) or about the fact that this PR introduces a (soft) guarantee about a compiler generated name. Although, regarding the later, I think the same reasoning applies here as it does for debuginfo in general.
r? ````@tmandry````
Add the generic_associated_types_extended feature
Right now, this only ignore obligations that reference new placeholders in `poly_project_and_unify_type`. In the future, this might do other things, like allowing object-safe GATs.
**This feature is *incomplete* and quite likely unsound. This is mostly just for testing out potential future APIs using a "relaxed" set of rules until we figure out *proper* rules.**
Also drive by cleanup of adding a `ProjectAndUnifyResult` enum instead of using a `Result<Result<Option>>`.
r? `@nikomatsakis`
Fix `cargo run tidy`
When I implemented rust-only bootstrapping in https://github.com/rust-lang/rust/pull/92260,
I neglected to test stage0 tools - it turns out they were broken because
they couldn't find the sysroot of the initial bootstrap compiler.
This fixes stage0 tools by using `rustc --print sysroot` instead of assuming rustc is already in a
sysroot and hard-coding the relative directory.
Fixes https://github.com/rust-lang/rust/issues/94797 (properly, without having to change rustup).
Remember mutability in `DefKind::Static`.
This allows to compute the `BodyOwnerKind` from `DefKind` only, and
removes a direct dependency of some MIR queries onto HIR.
As a side effect, it also simplifies metadata, since we don't need 4
flavours of `EntryKind::*Static` any more.
Yet more `parse_tt` improvements
Including lots of comment improvements, and an overhaul of how `matches` work that gives big speedups.
r? `@petrochenkov`
allow arbitrary inherent impls for builtin types in core
Part of https://github.com/rust-lang/compiler-team/issues/487. Slightly adjusted after some talks with `@m-ou-se` about the requirements of `t-libs-api`.
This adds a crate attribute `#![rustc_coherence_is_core]` which allows arbitrary impls for builtin types in core.
For other library crates impls for builtin types should be avoided if possible. We do have to allow the existing stable impls however. To prevent us from accidentally adding more of these in the future, there is a second attribute `#[rustc_allow_incoherent_impl]` which has to be added to **all impl items**. This only supports impls for builtin types but can easily be extended to additional types in a future PR.
This implementation does not check for overlaps in these impls. Perfectly checking that requires us to check the coherence of these incoherent impls in every crate, as two distinct dependencies may add overlapping methods. It should be easy enough to detect if it goes wrong and the attribute is only intended for use inside of std.
The first two commits are mostly unrelated cleanups.
Strict Provenance MVP
This patch series examines the question: how bad would it be if we adopted
an extremely strict pointer provenance model that completely banished all
int<->ptr casts.
The key insight to making this approach even *vaguely* pallatable is the
ptr.with_addr(addr) -> ptr
function, which takes a pointer and an address and creates a new pointer
with that address and the provenance of the input pointer. In this way
the "chain of custody" is completely and dynamically restored, making the
model suitable even for dynamic checkers like CHERI and Miri.
This is not a formal model, but lots of the docs discussing the model
have been updated to try to the *concept* of this design in the hopes
that it can be iterated on.
See #95228
Rollup of 5 pull requests
Successful merges:
- #95294 (Document Linux kernel handoff in std::io::copy and std::fs::copy)
- #95443 (Clarify how `src/tools/x` searches for python)
- #95452 (fix since field version for termination stabilization)
- #95460 (Spellchecking compiler code)
- #95461 (Spellchecking some comments)
Failed merges:
r? `@ghost`
`@rustbot` modify labels: rollup
Lazy type-alias-impl-trait take two
### user visible change 1: RPIT inference from recursive call sites
Lazy TAIT has an insta-stable change. The following snippet now compiles, because opaque types can now have their hidden type set from wherever the opaque type is mentioned.
```rust
fn bar(b: bool) -> impl std::fmt::Debug {
if b {
return 42
}
let x: u32 = bar(false); // this errors on stable
99
}
```
The return type of `bar` stays opaque, you can't do `bar(false) + 42`, you need to actually mention the hidden type.
### user visible change 2: divergence between RPIT and TAIT in return statements
Note that `return` statements and the trailing return expression are special with RPIT (but not TAIT). So
```rust
#![feature(type_alias_impl_trait)]
type Foo = impl std::fmt::Debug;
fn foo(b: bool) -> Foo {
if b {
return vec![42];
}
std::iter::empty().collect() //~ ERROR `Foo` cannot be built from an iterator
}
fn bar(b: bool) -> impl std::fmt::Debug {
if b {
return vec![42]
}
std::iter::empty().collect() // Works, magic (accidentally stabilized, not intended)
}
```
But when we are working with the return value of a recursive call, the behavior of RPIT and TAIT is the same:
```rust
type Foo = impl std::fmt::Debug;
fn foo(b: bool) -> Foo {
if b {
return vec![];
}
let mut x = foo(false);
x = std::iter::empty().collect(); //~ ERROR `Foo` cannot be built from an iterator
vec![]
}
fn bar(b: bool) -> impl std::fmt::Debug {
if b {
return vec![];
}
let mut x = bar(false);
x = std::iter::empty().collect(); //~ ERROR `impl Debug` cannot be built from an iterator
vec![]
}
```
### user visible change 3: TAIT does not merge types across branches
In contrast to RPIT, TAIT does not merge types across branches, so the following does not compile.
```rust
type Foo = impl std::fmt::Debug;
fn foo(b: bool) -> Foo {
if b {
vec![42_i32]
} else {
std::iter::empty().collect()
//~^ ERROR `Foo` cannot be built from an iterator over elements of type `_`
}
}
```
It is easy to support, but we should make an explicit decision to include the additional complexity in the implementation (it's not much, see a721052457cf513487fb4266e3ade65c29b272d2 which needs to be reverted to enable this).
### PR formalities
previous attempt: #92007
This PR also includes #92306 and #93783, as they were reverted along with #92007 in #93893fixes#93411fixes#88236fixes#89312fixes#87340fixes#86800fixes#86719fixes#84073fixes#83919fixes#82139fixes#77987fixes#74282fixes#67830fixes#62742fixes#54895
