Rollup of 7 pull requests #128719
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Rollup of 7 pull requests #128719
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The new sort implementations have the ability to detect Ord violations in many cases. This commit improves the message in a way that should help users realize what went wrong in their program.
…ble* - Move panic information into # Panics section - Fix mentions of T: Ord that should be compare - Add missing information
- Use if the implementation of [`Ord`] for `T` language - Link to total order wiki page - Rework total order help and examples - Improve language to be more precise and less prone to misunderstandings. - Fix usage of `sort_unstable_by` in `sort_by` example - Fix missing author mention - Use more consistent example input for sort - Use more idiomatic assert_eq! in examples - Use more natural "comparison function" language instead of "comparator function"
Since [1], `Cargo.lock` was split into `Cargo.lock` and `library/Cargo.lock`. Update Triagebot to give the same warning for both. [1]: rust-lang#128534
When encountering an E0277, if the type and the trait both come from a crate with the same name but different crate number, we explain that there are multiple crate versions in the dependency tree.
If there's a type that fulfills the bound, and it has the same name as the passed in type and has the same crate name, we explain that the same type in two different versions of the same crate *are different*.
```
error[E0277]: the trait bound `Type: dependency::Trait` is not satisfied
--> src/main.rs:4:18
|
4 | do_something(Type);
| ------------ ^^^^ the trait `dependency::Trait` is not implemented for `Type`
| |
| required by a bound introduced by this call
|
help: you have multiple different versions of crate `dependency` in your dependency graph
--> src/main.rs:1:5
|
1 | use bar::do_something;
| ^^^ one version of crate `dependency` is used here, as a dependency of crate `bar`
2 | use dependency::Type;
| ^^^^^^^^^^ one version of crate `dependency` is used here, as a direct dependency of the current crate
note: two types coming from two different versions of the same crate are different types even if they look the same
--> /home/gh-estebank/crate_versions/baz-2/src/lib.rs:1:1
|
1 | pub struct Type;
| ^^^^^^^^^^^^^^^ this type doesn't implement the required trait
|
::: /home/gh-estebank/crate_versions/baz/src/lib.rs:1:1
|
1 | pub struct Type;
| ^^^^^^^^^^^^^^^ this type implements the required trait
2 | pub trait Trait {}
| --------------- this is the required trait
note: required by a bound in `bar::do_something`
--> /home/gh-estebank/crate_versions/baz/src/lib.rs:4:24
|
4 | pub fn do_something<X: Trait>(_: X) {}
| ^^^^^ required by this bound in `do_something`
```
Address rust-lang#22750.
… r=fee1-dead Stabilize `min_exhaustive_patterns` ## Stabilisation report I propose we stabilize the [`min_exhaustive_patterns`](rust-lang#119612) language feature. With this feature, patterns of empty types are considered unreachable when matched by-value. This allows: ```rust enum Void {} fn foo() -> Result<u32, Void>; fn main() { let Ok(x) = foo(); // also match foo() { Ok(x) => ..., } } ``` This is a subset of the long-unstable [`exhaustive_patterns`](rust-lang#51085) feature. That feature is blocked because omitting empty patterns is tricky when *not* matched by-value. This PR stabilizes the by-value case, which is not tricky. The not-by-value cases (behind references, pointers, and unions) stay as they are today, e.g. ```rust enum Void {} fn foo() -> Result<u32, &Void>; fn main() { let Ok(x) = foo(); // ERROR: missing `Err(_)` } ``` The consequence on existing code is some extra "unreachable pattern" warnings. This is fully backwards-compatible. ### Comparison with today's rust This proposal only affects match checking of empty types (i.e. types with no valid values). Non-empty types behave the same with or without this feature. Note that everything below is phrased in terms of `match` but applies equallly to `if let` and other pattern-matching expressions. To be precise, a visibly empty type is: - an enum with no variants; - the never type `!`; - a struct with a *visible* field of a visibly empty type (and no #[non_exhaustive] annotation); - a tuple where one of the types is visibly empty; - en enum with all variants visibly empty (and no `#[non_exhaustive]` annotation); - a `[T; N]` with `N != 0` and `T` visibly empty; - all other types are nonempty. (An extra change was proposed below: that we ignore #[non_exhaustive] for structs since adding fields cannot turn an empty struct into a non-empty one) For normal types, exhaustiveness checking requires that we list all variants (or use a wildcard). For empty types it's more subtle: in some cases we require a `_` pattern even though there are no valid values that can match it. This is where the difference lies regarding this feature. #### Today's rust Under today's rust, a `_` is required for all empty types, except specifically: if the matched expression is of type `!` (the never type) or `EmptyEnum` (where `EmptyEnum` is an enum with no variants), then the `_` is not required. ```rust let foo: Result<u32, !> = ...; match foo { Ok(x) => ..., Err(_) => ..., // required } let foo: Result<u32, &!> = ...; match foo { Ok(x) => ..., Err(_) => ..., // required } let foo: &! = ...; match foo { _ => ..., // required } fn blah(foo: (u32, !)) { match foo { _ => ..., // required } } unsafe { let ptr: *const ! = ...; match *ptr {} // allowed let ptr: *const (u32, !) = ...; match *ptr { (x, _) => { ... } // required } let ptr: *const Result<u32, !> = ...; match *ptr { Ok(x) => { ... } Err(_) => { ... } // required } } ``` #### After this PR After this PR, a pattern of an empty type can be omitted if (and only if): - the match scrutinee expression has type `!` or `EmptyEnum` (like before); - *or* the empty type is matched by value (that's the new behavior). In all other cases, a `_` is required to match on an empty type. ```rust let foo: Result<u32, !> = ...; match foo { Ok(x) => ..., // `Err` not required } let foo: Result<u32, &!> = ...; match foo { Ok(x) => ..., Err(_) => ..., // required because `!` is under a dereference } let foo: &! = ...; match foo { _ => ..., // required because `!` is under a dereference } fn blah(foo: (u32, !)) { match foo {} // allowed } unsafe { let ptr: *const ! = ...; match *ptr {} // allowed let ptr: *const (u32, !) = ...; match *ptr { (x, _) => { ... } // required because the matched place is under a (pointer) dereference } let ptr: *const Result<u32, !> = ...; match *ptr { Ok(x) => { ... } Err(_) => { ... } // required because the matched place is under a (pointer) dereference } } ``` ### Documentation The reference does not say anything specific about exhaustiveness checking, hence there is nothing to update there. The nomicon does, I opened rust-lang/nomicon#445 to reflect the changes. ### Tests The relevant tests are in `tests/ui/pattern/usefulness/empty-types.rs`. ### Unresolved Questions None that I know of.
…r=fee1-dead
On trait bound mismatch, detect multiple crate versions in dep tree
When encountering an E0277, if the type and the trait both come from a crate with the same name but different crate number, we explain that there are multiple crate versions in the dependency tree.
If there's a type that fulfills the bound, and it has the same name as the passed in type and has the same crate name, we explain that the same type in two different versions of the same crate *are different*.
```
error[E0277]: the trait bound `Type: dependency::Trait` is not satisfied
--> src/main.rs:4:18
|
4 | do_something(Type);
| ------------ ^^^^ the trait `dependency::Trait` is not implemented for `Type`
| |
| required by a bound introduced by this call
|
help: you have multiple different versions of crate `dependency` in your dependency graph
--> src/main.rs:1:5
|
1 | use bar::do_something;
| ^^^ one version of crate `dependency` is used here, as a dependency of crate `bar`
2 | use dependency::Type;
| ^^^^^^^^^^ one version of crate `dependency` is used here, as a direct dependency of the current crate
note: two types coming from two different versions of the same crate are different types even if they look the same
--> /home/gh-estebank/crate_versions/baz-2/src/lib.rs:1:1
|
1 | pub struct Type;
| ^^^^^^^^^^^^^^^ this type doesn't implement the required trait
|
::: /home/gh-estebank/crate_versions/baz/src/lib.rs:1:1
|
1 | pub struct Type;
| ^^^^^^^^^^^^^^^ this type implements the required trait
2 | pub trait Trait {}
| --------------- this is the required trait
note: required by a bound in `bar::do_something`
--> /home/gh-estebank/crate_versions/baz/src/lib.rs:4:24
|
4 | pub fn do_something<X: Trait>(_: X) {}
| ^^^^^ required by this bound in `do_something`
```
Address rust-lang#22750.
…elp, r=workingjubilee Improve `Ord` violation help Recent experience in rust-lang#128083 showed that the panic message when an Ord violation is detected by the new sort implementations can be confusing. So this PR aims to improve it, together with minor bug fixes in the doc comments for sort*, sort_unstable* and select_nth_unstable*. Is it possible to get these changes into the 1.81 release? It doesn't change behavior and would greatly help when users encounter this panic for the first time, which they may after upgrading to 1.81. Tagging `@orlp`
…k-Simulacrum implement BufReader::peek Part of rust-lang#128405
Forbid unused unsafe in vxworks-specific std modules Tracking issue rust-lang#127747 Adding deny(unsafe_op_in_unsafe_fn) in VxWorks specific files did not cause any error. Most of VxWorks falls back on Unix libraries. So we'll have to wait for Unix changes. r? `@workingjubilee`
…Simulacrum Add a triagebot mention for `library/Cargo.lock` Since [1], `Cargo.lock` was split into `Cargo.lock` and `library/Cargo.lock`. Update Triagebot to give the same warning for both. [1]: rust-lang#128534
Don't ICE when getting an input file name's stem fails Fixes rust-lang#128681 The file stem is only used as a user-friendly prefix on intermediary files. While nice to have, it's not the end of the world if it fails so there's no real reason to emit an error here. We can continue with a fixed name as we do when an anonymous string is used.
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@bors r+ rollup=never p=7 |
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…iaskrgr Rollup of 7 pull requests Successful merges: - rust-lang#122792 (Stabilize `min_exhaustive_patterns`) - rust-lang#124944 (On trait bound mismatch, detect multiple crate versions in dep tree) - rust-lang#128273 (Improve `Ord` violation help) - rust-lang#128406 (implement BufReader::peek) - rust-lang#128539 (Forbid unused unsafe in vxworks-specific std modules) - rust-lang#128692 (Add a triagebot mention for `library/Cargo.lock`) - rust-lang#128710 (Don't ICE when getting an input file name's stem fails) r? `@ghost` `@rustbot` modify labels: rollup
|
The job Click to see the possible cause of the failure (guessed by this bot) |
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💔 Test failed - checks-actions |
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☔ The latest upstream changes (presumably #126804) made this pull request unmergeable. Please resolve the merge conflicts. |
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Successful merges:
min_exhaustive_patterns#122792 (Stabilizemin_exhaustive_patterns)Ordviolation help #128273 (ImproveOrdviolation help)library/Cargo.lock#128692 (Add a triagebot mention forlibrary/Cargo.lock)r? @ghost
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