Rollup of 7 pull requests
Successful merges:
- #75802 (resolve: Do not put nonexistent crate `meta` into prelude)
- #76607 (Modify executable checking to be more universal)
- #77851 (BTreeMap: refactor Entry out of map.rs into its own file)
- #78043 (Fix grammar in note for orphan-rule error [E0210])
- #78048 (Suggest correct place to add `self` parameter when inside closure)
- #78050 (Small CSS cleanup)
- #78059 (Set `MDBOOK_OUTPUT__HTML__INPUT_404` on linkchecker)
Failed merges:
r? `@ghost`
Suggest correct place to add `self` parameter when inside closure
It would incorrectly suggest adding it as a parameter to the closure instead of the containing function.
[For example](https://play.rust-lang.org/?version=stable&mode=debug&edition=2018&gist=1936bcd1e5f981573386e0cee985c3c0):
```
help: add a `self` receiver parameter to make the associated `fn` a method
|
5 | let _ = || self&self;
| ^^^^^
```
`DiagnosticMetadata.current_function` is only used for these messages so tweaking its behavior should be ok.
Fix grammar in note for orphan-rule error [E0210]
Fixes the grammar in the error note for [E0210] from:
_"= note: implementing a foreign trait is only possible if at least one of the types for which **is it** implemented is local"_
to:
_"= note: implementing a foreign trait is only possible if at least one of the types for which **it is** implemented is local"_
The content of this commit is the result of running the following command at the repository root:
`find . \( -type d -name .git -prune \) -o -type f -print0 | xargs -0 sed -i 's/which is it implemented/which it is implemented/g'`
resolve: Do not put nonexistent crate `meta` into prelude
Before the 2018 edition release there was some vague suggestion about adding a crate named `meta` to the standard distribution.
On this basis the name `meta` was "partially reserved" by putting `meta` into extern prelude (this means importing something named `meta` will result in an ambiguity error, for example).
This only caused confusion so far, and two years later there are no specific plans to add such crate.
If some standard crate (named `meta` or not) is added in the future, then cargo will hopefully already have ability to put it into extern prelude explicitly through `Cargo.toml`.
Otherwise, it could be added to extern prelude by the compiler at edition boundary.
Closes https://github.com/rust-lang/rust/issues/73948
BTreeMap: improve gdb introspection of BTreeMap with ZST keys or values
I accidentally pushed an earlier revision in #77788: it changes the index of tuples for BTreeSet from ""[{}]".format(i) to "key{}".format(i). Which doesn't seem to make the slightest difference on my linux box nor on CI. In fact, gdb doesn't make any distinction between "key{}" and "val{}" for a BTreeMap either, leading to confusing output if you test more. But easy to improve.
r? @Mark-Simulacrum
Permit uninhabited enums to cast into ints
This essentially reverts part of #6204; it is unclear why that [commit](https://github.com/rust-lang/rust/pull/6204/commits/c0f587de34f30b060df8a88c4068740e587b9340) was introduced, and I suspect no one remembers.
The changed code was only called from casting checks and appears to not affect any callers of that code (other than permitting this one case).
Fixes#75647.
Suggest minimal subset features in `incomplete_features` lint
This tells users that we have a minimal subset feature of it and they can fix the lint warning without allowing it.
The wording improvement is helpful :)
Fixes#77913
resolve: further improvements to "try using the enum's variant" diagnostic
Follow-up on https://github.com/rust-lang/rust/pull/77341#issuecomment-702738281.
This PR improves the diagnostic modified in #77341 to suggest not only those variants which do not have fields, but those with fields (by suggesting with placeholders). In addition, the wording of the tuple-variant-only case is improved slightly.
I've not made further changes to the tuple-variant-only case (e.g. to only suggest variants with the correct number of fields) because I don't think I have enough information to do so reliably (e.g. in the case where there is an attempt to construct a tuple variant, I have no information on how many fields were provided; and in the case of pattern matching, I only have a slice of spans and would need to check for things like `..` in those spans, which doesn't seem worth it).
r? @estebank
stabilize union with 'ManuallyDrop' fields and 'impl Drop for Union'
As [discussed by @SimonSapin and @withoutboats](https://github.com/rust-lang/rust/issues/55149#issuecomment-634692020), this PR proposes to stabilize parts of the `untagged_union` feature gate:
* It will be possible to have a union with field type `ManuallyDrop<T>` for any `T`.
* While at it I propose we also stabilize `impl Drop for Union`; to my knowledge, there are no open concerns around this feature.
In the RFC discussion, we also talked about allowing `&mut T` as another non-`Copy` non-dropping type, but that felt to me like an overly specific exception so I figured we'd wait if there is actually any use for such a special case.
Some things remain unstable and still require the `untagged_union` feature gate:
* Union with fields that do not drop, are not `Copy`, and are not `ManuallyDrop<_>`. The reason to not stabilize this is to avoid semver concerns around libraries adding `Drop` implementations later. (This is already not fully semver compatible as, to my knowledge, the borrow checker will exploit the non-dropping nature of any type, but it seems prudent to avoid further increasing the amount of trouble adding an `impl Drop` can cause.)
Due to this, quite a few tests still need the `untagged_union` feature, but I think the ones where I could remove the feature flag provide good test coverage for the stable part.
Cc @rust-lang/lang
Prevent miscompilation in trivial loop {}
Ideally, we would want to handle a broader set of cases to fully fix the
underlying bug here. That is currently relatively expensive at compile and
runtime, so we don't do that for now.
Performance results indicate this is not a major regression, if at all, so it should be safe to land.
cc #28728
Create a single source scope for promoteds
A promoted inherits all scopes from the parent body. At the same time,
almost all statements and terminators inside the promoted body so far
refer only to one of those scopes: the outermost one.
Instead of inheriting all scopes, inherit only a single scope
corresponding to the location of the promoted, making sure that there
are no references to other scopes.
Stabilize move_ref_pattern
# Implementation
- Initially the rule was added in the run-up to 1.0. The AST-based borrow checker was having difficulty correctly enforcing match expressions that combined ref and move bindings, and so it was decided to simplify forbid the combination out right.
- The move to MIR-based borrow checking made it possible to enforce the rules in a finer-grained level, but we kept the rule in place in an effort to be conservative in our changes.
- In #68376, @Centril lifted the restriction but required a feature-gate.
- This PR removes the feature-gate.
Tracking issue: #68354.
# Description
This PR is to stabilize the feature `move_ref_pattern`, which allows patterns
containing both `by-ref` and `by-move` bindings at the same time.
For example: `Foo(ref x, y)`, where `x` is `by-ref`,
and `y` is `by-move`.
The rules of moving a variable also apply here when moving *part* of a variable,
such as it can't be referenced or moved before.
If this pattern is used, it would result in *partial move*, which means that
part of the variable is moved. The variable that was partially moved from
cannot be used as a whole in this case, only the parts that are still
not moved can be used.
## Documentation
- The reference (rust-lang/reference#881)
- Rust by example (rust-lang/rust-by-example#1377)
## Tests
There are many tests, but I think one of the comperhensive ones:
- [borrowck-move-ref-pattern-pass.rs](85fbf49ce0/src/test/ui/pattern/move-ref-patterns/borrowck-move-ref-pattern-pass.rs)
- [borrowck-move-ref-pattern.rs](85fbf49ce0/src/test/ui/pattern/move-ref-patterns/borrowck-move-ref-pattern.rs)
# Examples
```rust
#[derive(PartialEq, Eq)]
struct Finished {}
#[derive(PartialEq, Eq)]
struct Processing {
status: ProcessStatus,
}
#[derive(PartialEq, Eq)]
enum ProcessStatus {
One,
Two,
Three,
}
#[derive(PartialEq, Eq)]
enum Status {
Finished(Finished),
Processing(Processing),
}
fn check_result(_url: &str) -> Status {
// fetch status from some server
Status::Processing(Processing {
status: ProcessStatus::One,
})
}
fn wait_for_result(url: &str) -> Finished {
let mut previous_status = None;
loop {
match check_result(url) {
Status::Finished(f) => return f,
Status::Processing(p) => {
match (&mut previous_status, p.status) {
(None, status) => previous_status = Some(status), // first status
(Some(previous), status) if *previous == status => {} // no change, ignore
(Some(previous), status) => { // Now it can be used
// new status
*previous = status;
}
}
}
}
}
}
```
Before, we would have used:
```rust
match (&previous_status, p.status) {
(Some(previous), status) if *previous == status => {} // no change, ignore
(_, status) => {
// new status
previous_status = Some(status);
}
}
```
Demonstrating *partial move*
```rust
fn main() {
#[derive(Debug)]
struct Person {
name: String,
age: u8,
}
let person = Person {
name: String::from("Alice"),
age: 20,
};
// `name` is moved out of person, but `age` is referenced
let Person { name, ref age } = person;
println!("The person's age is {}", age);
println!("The person's name is {}", name);
// Error! borrow of partially moved value: `person` partial move occurs
//println!("The person struct is {:?}", person);
// `person` cannot be used but `person.age` can be used as it is not moved
println!("The person's age from person struct is {}", person.age);
}
```
Refactor io/buffered.rs into submodules
This pull request splits `BufWriter`, `BufReader`, `LineWriter`, and `LineWriterShim` (along with their associated tests) into separate submodules. It contains no functional changes. This change is being made in anticipation of adding another type of buffered writer which can be switched between line- and block-buffering mode.
Part of a series of pull requests resolving #60673.
mangling: mangle impl params w/ v0 scheme
This PR modifies v0 symbol mangling to include all generic parameters from impl blocks (not just those used in the self type) - an alternative fix to #75326.
```
original:
_RNCNvXCs4fqI2P2rA04_19impl_param_manglingINtB4_3FooppENtNtNtNtCsfnEnqCNU58Z_4core4iter6traits8iterator8Iterator4next0B4_
// |------------ B4_ ----------------|
// _R (N C (N v (X (C ((s 4fqI2p2rA04_) 19impl_param_mangling)) (I (N t B4_ 3Foo) pp E) (N t (N t (N t (N t (C ((s fnEnqCNU58Z_) 4core)) 4iter) 6traits) 8iterator) 8Iterator)) 4next) 0) B4_
modified:
_RNvXINICs4fqI2P2rA04_11issue_753260pppEINtB5_3FooppENtNtNtNtCsfnEnqCNU58Z_4core4iter6traits8iterator8Iterator4nextB5_
// _R (N v (X (I (N I (C ((s 4fqI2P2rA04_) 11issue_75326)) 0) ppp E) (I (N t B5_ 3Foo) pp E) (N t (N t (N t (N t (C ((s fnEnqCNU58Z_) 4core)) 4iter) 6traits) 8iterator) 8Iterator)) 4next) B5_
// | ^ |
// | | |
// | new impl namespace |
```
~~Submitted as a draft as after some discussion w/ @eddyb, I'm going to do some investigation into (yet more alternative) changes to polymorphization that might remove the necessity for this.~~
r? @eddyb
This commit improves the tuple struct case added in rust-lang/rust#77341
so that the context is mentioned in more of the message.
Signed-off-by: David Wood <david@davidtw.co>
This commit improves the diagnostic modified in rust-lang/rust#77341 to
suggest not only those variants which do not have fields, but those with
fields (by suggesting with placeholders).
Signed-off-by: David Wood <david@davidtw.co>
Ideally, we would want to handle a broader set of cases to fully fix the
underlying bug here. That is currently relatively expensive at compile and
runtime, so we don't do that for now.
This commit modifies v0 symbol mangling to include all generic
parameters from impl blocks (not just those used in the self type).
Signed-off-by: David Wood <david@davidtw.co>
Replace tuple of infer vars for upvar_tys with single infer var
This commit allows us to decide the number of captures required after
completing capture ananysis, which is required as part of implementing
RFC-2229.
closes https://github.com/rust-lang/project-rfc-2229/issues/4
r? `@nikomatsakis`
