wildcard_enum_match_arm lint takes the enum origin into account
fixes#7419
---
changelog: Enhancement: [`wildcard_enum_match_arm`]: Now lints missing private variants, for local enums
[#10250](https://github.com/rust-lang/rust-clippy/pull/10250)
<!-- changelog_checked -->
Fix version declared for semicolon_inside_block and semicolon_outside…
As per Issue #10244, the lint were documentated
as being part of 1.66.0 but will actually be
released 1.68.0 .
changelog: [`semicolon_inside_block`]: Documentation fix
Fixes#10244
Mark uninlined_format_args as pedantic
Fixes https://github.com/rust-lang/rust-clippy/issues/10087
We should restore this when rust-analyzer support gets better. Worth filing an issue to track.
changelog: Mark [`uninlined_format_args`] as `pedantic`
[`unused_io_amount`]: Lint with `is_ok` and `is_err`
Fixes#10132
changelog: Apply [`unused_io_amount`] lint to `is_ok` and `is_err` without checking read/write amount
prevents `len_without_is_empty` from yielding positive when `len` takes arguments besides `&self`
Fixes#9520
---
changelog: FP [`len_without_is_empty`]: No longer lints, if `len` as a non-default signature
[#10255](https://github.com/rust-lang/rust-clippy/pull/10255)
<!-- changelog_checked -->
more than just `&self` in non-standard implementations.
changelog: Fix [`len_without_is_empty`] false positive when len has a
non-standard method signature
Fixes#9520
`invalid_regex`: Show full error when string value doesn't match source
changelog: [`invalid_regex`]: Show full error when parsing non-literals or regular strings containing escape sequences
Fixes#4170, the escape sequence there causes the span to be incorrect which will have caused most of the confusion
Remove HirId -> LocalDefId map from HIR.
Having this map in HIR prevents the creating of new definitions after HIR has been built.
Thankfully, we do not need it.
Based on https://github.com/rust-lang/rust/pull/103902
Remove `ControlFlow::{BREAK, CONTINUE}`
Libs-API decided to remove these in #102697.
Follow-up to #107023, which removed them from `compiler/`, but a couple new ones showed up since that was merged.
r? libs
Remove overlapping parts of multipart suggestions
This PR adds a debug assertion that the parts of a single substitution cannot overlap, fixes a overlapping substitution from the testsuite, and fixes https://github.com/rust-lang/rust/issues/106870.
Note that a single suggestion can still have multiple overlapping substitutions / possible edits, we just don't suggest overlapping replacements in a single edit anymore.
I've also included a fix for an unrelated bug where rustfix for `explicit_outlives_requirements` would produce multiple trailing commas for a where clause.
Compute generator saved locals on MIR
Generators are currently type-checked by introducing a `witness` type variable, which is unified with a `GeneratorWitness(captured types)` whose purpose is to ensure that the auto traits correctly migrate from the captured types to the `witness` type. This requires computing the captured types on HIR during type-checking, only to re-do it on MIR later.
This PR proposes to drop the HIR-based computation, and only keep the MIR one. This is done in 3 steps.
1. During type-checking, the `witness` type variable is never unified. This allows to stall all the obligations that depend on it until the end of type-checking. Then, the stalled obligations are marked as successful, and saved into the typeck results for later verification.
2. At type-checking writeback, `witness` is replaced by `GeneratorWitnessMIR(def_id, substs)`. From this point on, all trait selection involving `GeneratorWitnessMIR` will fetch the MIR-computed locals, similar to what opaque types do. There is no lifetime to be preserved here: we consider all the lifetimes appearing in this witness type to be higher-ranked.
3. After borrowck, the stashed obligations are verified against the actually computed types, in the `check_generator_obligations` query. If any obligation was wrongly marked as fulfilled in step 1, it should be reported here.
There are still many issues:
- ~I am not too happy having to filter out some locals from the checked bounds, I think this is MIR building that introduces raw pointers polluting the analysis;~ solved by a check specific to static variables.
- the diagnostics for captured types don't show where they are used/dropped;
- I do not attempt to support chalk.
cc `@eholk` `@jyn514` for the drop-tracking work
r? `@oli-obk` as you warned me of potential unsoundness
Move format_args!() into AST (and expand it during AST lowering)
Implements https://github.com/rust-lang/compiler-team/issues/541
This moves FormatArgs from rustc_builtin_macros to rustc_ast_lowering. For now, the end result is the same. But this allows for future changes to do smarter things with format_args!(). It also allows Clippy to directly access the ast::FormatArgs, making things a lot easier.
This change turns the format args types into lang items. The builtin macro used to refer to them by their path. After this change, the path is no longer relevant, making it easier to make changes in `core`.
This updates clippy to use the new language items, but this doesn't yet make clippy use the ast::FormatArgs structure that's now available. That should be done after this is merged.
use LocalDefId instead of HirId in trait resolution to simplify
the obligation clause resolution
Signed-off-by: Vincenzo Palazzo <vincenzopalazzodev@gmail.com>
Use UnordMap and UnordSet for id collections (DefIdMap, LocalDefIdMap, etc)
This PR changes the `rustc_data_structures::define_id_collections!` macro to use `UnordMap` and `UnordSet` instead of `FxHashMap` and `FxHashSet`. This should account for a large portion of hash-maps being used in places where they can cause trouble.
The changes required are moderate but non-zero:
- In some places the collections are extracted into sorted vecs.
- There are a few instances where for-loops have been changed to extends.
~~Let's see what the performance impact is. With a bit more refactoring, we might be able to get rid of some of the additional sorting -- but the change set is already big enough. Unless there's a performance impact, I'd like to do further changes in subsequent PRs.~~
Performance does not seem to be negatively affected ([perf-run here](https://github.com/rust-lang/rust/pull/106977#issuecomment-1396776699)).
Part of [MCP 533](https://github.com/rust-lang/compiler-team/issues/533).
r? `@ghost`
Add `multiple_unsafe_ops_per_block` lint
Adds a lint, which restricts an `unsafe` block to only one unsafe operation.
Closes#10064
---
changelog: New lint: [`multiple_unsafe_ops_per_block`]
[#10206](https://github.com/rust-lang/rust-clippy/pull/10206)
<!-- changelog_checked -->
Fix suggestion in `transmutes_expressible_as_ptr_casts` when the source type is a borrow.
fixes#9894
changelog: `transmutes_expressible_as_ptr_casts`: Fix suggestion when the source type is a borrow.
[needless_return]: Remove all semicolons on suggestion
Closes#10182
Multiple semicolons currently breaks autofix for `needless_return` suggestions. Any semicolons left after removing return means that the return type will always be `()`, and thus fail to compile.
This PR allows `needless_return` to remove multiple semicolons.
The change won't cover the case where there is multiple line yet.
i.e.
```rust
fn needless_return() -> bool {
return true;
;;
}
```
---
changelog: Sugg: [`needless_return`]: Now removes all semicolons on the same line
[#10187](https://github.com/rust-lang/rust-clippy/pull/10187)
<!-- changelog_checked -->
`cast_possible_truncation` Suggest TryFrom when truncation possible
This fixes the last issues from https://github.com/rust-lang/rust-clippy/pull/9664 as the author seems to be inactive. The PR author was sadly kept during the rebase, due to the conflict resolution.
IDK if it's worth it do to a full review, I only added the last commit, everything else remained the same, besides a rebase.
---
changelog: Sugg: [`cast_possible_truncation`]: Now suggests using `try_from` or allowing the lint
[#10038](https://github.com/rust-lang/rust-clippy/pull/10038)
<!-- changelog_checked -->
closes: https://github.com/rust-lang/rust-clippy/issues/9231
Allow implementing `Hash` with derived `PartialEq` (`derive_hash_xor_eq`
This is a common pattern and is totally allowed by the `Hash` trait.
Fixes#2627
changelog: Move: Renamed `derive_hash_xor_eq` to [`derived_hash_with_manual_eq`]
[#10184](https://github.com/rust-lang/rust-clippy/pull/10184)
changelog: Enhancement: [`derived_hash_with_manual_eq`]: Now allows `#[derive(PartialEq)]` with custom `Hash` implementations
[#10184](https://github.com/rust-lang/rust-clippy/pull/10184)
<!-- changelog_checked -->
trim paths in `suspicious_to_owned`
This continues my path trimming spree. I'm not going to add yet another changelog entry, we should have one "trim paths in some applicable lints" entry instead.
---
changelog: none
unused_self: Don't trigger if the method body contains todo!()
If the author is using todo!(), presumably they intend to use self at some point later, so we don't have a good basis to recommend factoring out to an associated function.
Fixes#10117.
---
changelog: Enhancement: [`unused_self`]: No longer lints, if the method body contains a `todo!()` call
[#10166](https://github.com/rust-lang/rust-clippy/pull/10166)
<!-- changelog_checked -->
[#10167] Clarify that the lint only works if x eq. y in a `for` loop.
Reading the documentation for the lint, one could expect that the lint works in all cases that `X == Y`. This is false.
While the lint was updated, the documentation wasn't.
More information about the `N..N` problem in #5689 and #5628
---
Fixes#10167
changelog: [`reversed_empty_ranges`]: Update and clarify documentation
Reading the documentation for the lint, one could expect that the lint works in all cases that `X == Y`. This is false.
While the lint was updated, the documentation wasn't.
More information about the `N..N` problem in #5689 and #5628
trim paths in `box_default`
This might help with #10089, though I have not tested that yet. In any event, it keeps the suggestion short and to the point.
---
changelog: Trim paths in [`box_default`] suggestion
trim paths in `default_trait_access`/`clone_on_copy` suggestions
This should help making the suggestions more palatable. Similar to #10153.
---
changelog: trim paths in [`default_trait_access`]/[`clone_on_copy`] suggestions
If the author is using todo!(), presumably they intend to use self at
some point later, so we don't have a good basis to recommend factoring
out to an associated function.
Fixes#10117.
changelog: Don't trigger [`unused_self`] if the method body contains a `todo!()` call
[`drop_ref`]: don't lint idiomatic in match arm
fixes#10122
As established in issue #9482, it is idiomatic to use a single `drop()` expression in a match arm to achieve a side-effect of a function while discarding its output. This should also apply to cases where the function returns a reference.
The change to the lint's code was less than 1 line, because all the heavy lifting was done in PR #9491.
---
changelog: FP: [`drop_ref`]: No longer lints idiomatic expression in `match` arms
[#10142](https://github.com/rust-lang/rust-clippy/pull/10142)
<!-- changelog_checked -->
Make the iter_kv_map lint handle ref/mut annotations.
For the degenerate (`map(|(k, _)| k)`/`map(|(_, v)| v)`) cases a mut annotation is superfluous and a ref annotation won't compile, so no additional handling is required. For cases where the `map` call must be preserved ref/mut annotations should also be presereved so that the map body continues to work as expected.
*Please write a short comment explaining your change (or "none" for internal only changes)*
changelog: [`iter_kv_map`]: handle ref/mut annotations
For the degenerate (`map(|(k, _)| k)`/`map(|(_, v)| v)`) cases a mut annotation is superfluous and a ref annotation won't compile, so no additional handling is required. For cases where the `map` call must be preserved ref/mut annotations should also be presereved so that the map body continues to work as expected.
don't lint field_reassign when field in closure
fixes#10136
This change makes the ContainsName struct visit all interior expressions, which means that ContainsName will return true even if `name` is used in a closure within `expr`.
---
changelog: FP: [`field_reassign_with_default`]: No longer lints cases, where values are initializes from closures capturing struct values
[#10143](https://github.com/rust-lang/rust-clippy/pull/10143)
<!-- changelog_checked -->
chore: fix identation of `if_chain` in `filter_map`
This is a really small fix.
If someone could take a look at it, I would appreciate it🙏
---
changelog: none
<!-- changelog_checked -->
This commit makes the ContainsName struct visit all interior
expressions, which means that ContainsName will return true
even if `name` is used in a closure within `expr`.
Move `mutex_atomic` to `restriction`
By #4295, the general consensus seems to be that `mutex_atomic` is not a useful lint in most cases. If anything, it could be useful as a restriction on code that for whatever reason can't use atomics. Keeping it in `clippy::nursery` is harmful to people attempting to use clippy for soundness.
---
changelog: Moved [`mutex_atomic`] to `restriction`
[#10115](https://github.com/rust-lang/rust-clippy/pull/10115)
<!-- chnagelog_checked -->
Rollup of 9 pull requests
Successful merges:
- #104531 (Provide a better error and a suggestion for `Fn` traits with lifetime params)
- #105899 (`./x doc library --open` opens `std`)
- #106190 (Account for multiple multiline spans with empty padding)
- #106202 (Trim more paths in obligation types)
- #106234 (rustdoc: simplify settings, help, and copy button CSS by not reusing)
- #106236 (docs/test: add docs and a UI test for `E0514` and `E0519`)
- #106259 (Update Clippy)
- #106260 (Fix index out of bounds issues in rustdoc)
- #106263 (Formatter should not try to format non-Rust files)
Failed merges:
r? `@ghost`
`@rustbot` modify labels: rollup
fix incorrect suggestion in `suboptimal_flops`
fixes#10003
There was an error when trying to negate an expression like `x - 1.0`. We used to format it as `-x - 1.0` whereas a proper negation would be `-(x - 1.0)`.
Therefore, we add parentheses around the expression when it is `ExprKind::Binary`.
We also add parentheses around multiply and divide expressions, even though this is not strictly necessary.
changelog: [`suboptimal_flops`]: fix incorrect suggestion caused by an incorrect negation of floating point expressions.
There was an error when trying to negate an expression
like `x - 1.0`. We used to format it as `-x - 1.0` whereas
a proper negation would be `-(x - 1.0)`.
Therefore, we add parentheses around the expression when it is a
Binary ExprKind.
We also add parentheses around multiply and divide expressions,
even though this is not strictly necessary.
This patch not only improves visibility, but also fixes a potential bug.
When a lint description ends with code block, the string will have three
backquotes at the end.
Since the current implementation prints the default value immediately
after that, the markdown renderer is unable to properly close the code
block.
Add size_of_ref lint
This addresses #9995, which is likely raising a valid point about `std::mem::size_of_val()`: It's [very easy to use double-references as the argument](https://github.com/apache/arrow-datafusion/pull/4371#discussion_r1032385224), which the function will happily accept and give back the size of _the reference_, not the size of the value _behind_ the reference. In the worst case, if the value matches the programmer's expectation, this seems to work, while in fact, everything will go horribly wrong e.g. on a different platform.
The size of a `&T` is independent of what `T` is, and people might want to use `std::mem::size_of_val()` to actually get the size of _any_ reference (e.g. via `&&()`). I would rather suggest that this is always bad behavior, though ([instead](https://doc.rust-lang.org/reference/type-layout.html#pointers-and-references-layout), [and](https://doc.rust-lang.org/stable/std/primitive.usize.html#associatedconstant.BITS)). I, therefore, put this lint into `correctness`.
Since the problem is usually easily fixed by removing extra `&`, I went light on suggesting code.
---
changelog: New lint: [`size_of_ref`]
[#10098](https://github.com/rust-lang/rust-clippy/pull/10098)
<!-- changelog_checked -->
Improve `possible_borrower`
This PR makes several improvements to `clippy_uitls::mir::possible_borrower`. These changes benefit both `needless_borrow` and `redundant clone`.
1. **Use the compiler's `MaybeStorageLive` analysis**
I could spot not functional differences between the one in the compiler and the one in Clippy's repository. So, I removed the latter in favor of the the former.
2. **Make `PossibleBorrower` a dataflow analysis instead of a visitor**
The main benefit of this change is that allows `possible_borrower` to take advantage of statements' relative locations, which is easier to do in an analysis than in a visitor.
This is easier to illustrate with an example, so consider this one:
```rust
fn foo(cx: &LateContext<'_>, lint: &'static Lint) {
cx.struct_span_lint(lint, rustc_span::Span::default(), "", |diag| diag.note(&String::new()));
// ^
}
```
We would like to flag the `&` pointed to by the `^` for removal. `foo`'s MIR begins like this:
```rust
fn span_lint::foo::{closure#0}(_1: [closure@$DIR/needless_borrow.rs:396:68: 396:74], _2: &mut rustc_errors::diagnostic_builder::DiagnosticBuilder<'_, ()>) -> &mut rustc_errors::diagnostic_builder::DiagnosticBuilder<'_, ()> {
debug diag => _2; // in scope 0 at $DIR/needless_borrow.rs:396:69: 396:73
let mut _0: &mut rustc_errors::diagnostic_builder::DiagnosticBuilder<'_, ()>; // return place in scope 0 at $DIR/needless_borrow.rs:396:75: 396:75
let mut _3: &mut rustc_errors::diagnostic_builder::DiagnosticBuilder<'_, ()>; // in scope 0 at $DIR/needless_borrow.rs:396:75: 396:100
let mut _4: &mut rustc_errors::diagnostic_builder::DiagnosticBuilder<'_, ()>; // in scope 0 at $DIR/needless_borrow.rs:396:75: 396:100
let mut _5: &std::string::String; // in scope 0 at $DIR/needless_borrow.rs:396:85: 396:99
let _6: std::string::String; // in scope 0 at $DIR/needless_borrow.rs:396:86: 396:99
bb0: {
StorageLive(_3); // scope 0 at $DIR/needless_borrow.rs:396:75: 396:100
StorageLive(_4); // scope 0 at $DIR/needless_borrow.rs:396:75: 396:100
_4 = &mut (*_2); // scope 0 at $DIR/needless_borrow.rs:396:75: 396:100
StorageLive(_5); // scope 0 at $DIR/needless_borrow.rs:396:85: 396:99
StorageLive(_6); // scope 0 at $DIR/needless_borrow.rs:396:86: 396:99
_6 = std::string::String::new() -> bb1; // scope 0 at $DIR/needless_borrow.rs:396:86: 396:99
// mir::Constant
// + span: $DIR/needless_borrow.rs:396:86: 396:97
// + literal: Const { ty: fn() -> std::string::String {std::string::String::new}, val: Value(<ZST>) }
}
bb1: {
_5 = &_6; // scope 0 at $DIR/needless_borrow.rs:396:85: 396:99
_3 = rustc_errors::diagnostic_builder::DiagnosticBuilder::<'_, ()>::note::<&std::string::String>(move _4, move _5) -> [return: bb2, unwind: bb4]; // scope 0 at $DIR/needless_borrow.rs:396:75: 396:100
// mir::Constant
// + span: $DIR/needless_borrow.rs:396:80: 396:84
// + literal: Const { ty: for<'a> fn(&'a mut rustc_errors::diagnostic_builder::DiagnosticBuilder<'_, ()>, &std::string::String) -> &'a mut rustc_errors::diagnostic_builder::DiagnosticBuilder<'_, ()> {rustc_errors::diagnostic_builder::DiagnosticBuilder::<'_, ()>::note::<&std::string::String>}, val: Value(<ZST>) }
}
```
The call to `diag.note` appears in `bb1` on the line beginning with `_3 =`. The `String` is owned by `_6`. So, in the call to `diag.note`, we would like to know whether there are any references to `_6` besides `_5`.
The old, visitor approach did not consider the relative locations of statements. So all borrows were treated the same, *even if they occurred after the location of interest*.
For example, before the `_3 = ...` call, the possible borrowers of `_6` would be just `_5`. But after the call, the possible borrowers would include `_2`, `_3`, and `_4`.
So, in a sense, the call from which we are try to remove the needless borrow is trying to prevent us from removing the needless borrow(!).
With an analysis, things do not get so muddled. We can determine the set of possible borrowers at any specific location, e.g., using a `ResultsCursor`.
3. **Change `only_borrowers` to `at_most_borrowers`**
`possible_borrowers` exposed a function `only_borrowers` that determined whether the borrowers of some local were *exactly* some set `S`. But, from what I can tell, this was overkill. For the lints that currently use `possible_borrower` (`needless_borrow` and `redundant_clone`), all we really want to know is whether there are borrowers *other than* those in `S`. (Put another way, we only care about the subset relation in one direction.) The new function `at_most_borrowers` takes this more tailored approach.
4. **Compute relations "on the fly" rather than using `transitive_relation`**
The visitor would compute and store the transitive closure of the possible borrower relation for an entire MIR body.
But with an analysis, there is effectively a different possible borrower relation at each location in the body. Computing and storing a transitive closure at each location would not be practical.
So the new approach is to compute the transitive closure on the fly, as needed. But the new approach might actually be more efficient, as I now explain.
In all current uses of `at_most_borrowers` (previously `only_borrowers`), the size of the set of borrowers `S` is at most 2. So you need only check at most three borrowers to determine whether the subset relation holds. That is, once you have found a third borrower, you can stop, since you know the relation cannot hold.
Note that `transitive_relation` is still used by `clippy_uitls::mir::possible_origin` (a kind of "subroutine" of `possible_borrower`).
cc: `@Jarcho`
---
changelog: [`needless_borrow`], [`redundant_clone`]: Now track references better and detect more cases
[#9701](https://github.com/rust-lang/rust-clippy/pull/9701)
<!-- changelog_checked -->
Avoid `match_wildcard_for_single_variants` on guarded wild matches
fix#9993
changelog: FP: [`match_wildcard_for_single_variants`]: No longer lints on wildcards with a guard
[#10056](https://github.com/rust-lang/rust-clippy/pull/10056)
<!-- changelog_checked -->
r? `@Jarcho`
Null fn lints
Adds lints to check for code, that assumes nullable `fn()`.
### Lint examples:
`transmute_null_to_fn`:
```rust
error: transmuting a known null pointer into a function pointer
--> $DIR/transmute_null_to_fn.rs:9:23
|
LL | let _: fn() = std::mem::transmute(std::ptr::null::<()>());
| ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ this transmute results in undefined behavior
|
= help: try wrapping your function pointer type in `Option<T>` instead, and using `None` as a null pointer value
```
`fn_null_check`:
```rust
error: function pointer assumed to be nullable, even though it isn't
--> $DIR/fn_null_check.rs:13:8
|
LL | if (fn_ptr as *mut ()).is_null() {}
| ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
|
= help: try wrapping your function pointer type in `Option<T>` instead, and using `is_none` to check for null pointer value
```
Closes#1644
---
changelog: Improvement: [`transmuting_null`]: Now detects `const` pointers to all types
[#10099](https://github.com/rust-lang/rust-clippy/pull/10099)
changelog: New lint: [`transmute_null_to_fn`]
[#10099](https://github.com/rust-lang/rust-clippy/pull/10099)
changelog: New lint: [`fn_null_check`]
[#10099](https://github.com/rust-lang/rust-clippy/pull/10099)
<!-- changelog_checked (This is just a flag for me, please don't add it manually) -->
Identify more cases of useless `into_iter()` calls
changelog: Sugg: [`useless_conversion`]: Now suggests removing calls to `into_iter()` on an expression implementing `Iterator`
[#10020](https://github.com/rust-lang/rust-clippy/pull/10020)
<!-- changelog_checked -->
If the type of the result of a call to `IntoIterator::into_iter()`
and the type of the receiver are the same, then the receiver
implements `Iterator` and `into_iter()` is the identity function.
The call to `into_iter()` may be removed in all but two cases:
- If the receiver implements `Copy`, `into_iter()` will produce
a copy of the receiver and cannot be removed. For example,
`x.into_iter().next()` will not advance `x` while `x.next()` will.
- If the receiver is an immutable local variable and the call to
`into_iter()` appears in a larger expression, removing the call to
`into_iter()` might cause mutability issues. For example, if `x`
is an immutable local variable, `x.into_iter().next()` will
compile while `x.next()` will not as `next()` receives
`&mut self`.
Rustup
r? `@ghost`
I'm on the train and my internet is too bad to download the necessary toolchain, so I have to use CI to find sync fallout.
changelog: none
<!-- changelog_checked -->
fix: not suggest seek_to_start_instead_of_rewind when expr is used
changelog: [`seek_to_start_instead_of_rewind`]: No longer lints, if the return of `seek` is used.
[#10096](https://github.com/rust-lang/rust-clippy/pull/10096)
<!-- changelog_checked -->
Fixes#10065
There used to be a logical bug where IncrementVisitor would
completely stop checking an expression/block after seeing a continue
statement. This led to issue #10058 where a variable incremented
(or otherwise modified) after any continue statement would still be
considered incremented only once.
The solution is to continue scanning the expression after seeing a
`continue` statement, but increment self.depth so that the Visitor
thinks that the rest of the loop is within a conditional.
Changelog 1.66
It's really nice to see a changelog with so many suggestion fixes and improvements. Not much else to say. This should be merged with the coming release on 2022-12-15. For the reviewer, please review it and approve it if it looks good. The merge should wait until the release :)
---
changelog: none
<!-- changelog_checked -->
improve `manual_is_ascii_check ` check
Sorry, not familiar the api, i can only check the method name of expression `<expr-1>.contains(<expr-2>)` after read clippy book and hints from #9933 . i dont know how to check
1. if <expr-1> is a specific range
2. <expr-2> is a character
r? `@xFrednet` could you please provide some more hints? 😝️
---
changelog: Enhancement: [`manual_is_ascii_check`]: Now detects ranges with `.contains()` calls
[#10053](https://github.com/rust-lang/rust-clippy/pull/10053)
<!-- changelog_checked -->
Remove `token::Lit` from `ast::MetaItemLit`.
Currently `ast::MetaItemLit` represents the literal kind twice. This PR removes that redundancy. Best reviewed one commit at a time.
r? `@petrochenkov`
Add 1.58 MSRV for `collapsible_str_replace`
The `Pattern` impl for `[char; N]` was added in 1.58
changelog: Enhancement: [`collapsible_str_replace`]: Now takes MSRV into consideration. The minimal version is 1.58
[#10047](https://github.com/rust-lang/rust-clippy/pull/10047)
add `suppress_restriction_lint_in_const` config
According to #9808 , add a new lint `suppress_lint_in_const` to report even in const context. BTW, i am not good at naming either, if anyone have a better idea, i am happy to change it.
This PR is still in progress, so i keep it draft.
- \[x] Followed [lint naming conventions][lint_naming]
- \[x] Added passing UI tests (including committed `.stderr` file)
- \[x] `cargo test` passes locally
- \[x] Executed `cargo dev update_lints`
- \[x] Added lint documentation
- \[x] Run `cargo dev fmt`
changelog: Enhancement: [`indexing_slicing`]: add new config `suppress-restriction-lint-in-const` to enable restriction lints, even if the suggestion might not be applicable
r? `@xFrendet`
Fix 10021
This PR proposes a fix for #10021.
The problem is similar to the one that `@mikerite` described in #9505. The compiler is generating an empty substitution for a call, even though the type of `Self` seems to be needed for a predicate. In `@mikerite's` case, the call was to [`IntoFuture::into_future`](https://doc.rust-lang.org/std/future/trait.IntoFuture.html#tymethod.into_future). In this case, the call is to [`Try::branch`](https://doc.rust-lang.org/std/ops/trait.Try.html#tymethod.branch).
The proposed fix is to verify that the parameter whose type is changing has an index within the substitution. The strikes me as a reasonable approach, since if the check were to fail, the following code would be a no-op:
4c123a06ba/clippy_lints/src/methods/unnecessary_to_owned.rs (L420-L428)
Like `@mikerite's` original solution, this solution turns ICEs into false negatives.
changelog: fix `unnecessary_to_owned` false positive involving `Try::branch`
Don't lint `implicit_clone` when the type doesn't implement clone
fixes#10019
changelog: `implicit_clone`: Don't lint when the type doesn't implement clone
Fix#9958
This PR fixes#9958. In order to fix the issue, the lint will now peel reference operators and enclose the expression with parentheses when necessary.
changelog: [`comparison_to_empty`]: Peel deref operators in suggestions when necessary
Don't lint `from_over_into` for opaque types
fixes#9935
This is stalled until the next sync. The impl in question can't be written on the pinned nightly.
changelog: Don't lint `from_over_into` for opaque types
rustc_ast_lowering: Stop lowering imports into multiple items
Lower them into a single item with multiple resolutions instead.
This also allows to remove additional `NodId`s and `DefId`s related to those additional items.
This is required to distinguish between cooked and raw byte string
literals in an `ast::LitKind`, without referring to an adjacent
`token::Lit`. It's a prerequisite for the next commit.
Lower them into a single item with multiple resolutions instead.
This also allows to remove additional `NodId`s and `DefId`s related to those additional items.
Don't lint `explicit_auto_deref` when the initial type is neither a reference, nor a receiver
fixes#9901fixes#9777
changelog: `explicit_auto_deref`: Don't lint when the initial value is neither a reference, nor a receiver
Don't cross contexts while building the suggestion for `redundant_closure_call`
fixes#9957
changelog: `redundant_closure_call`: Don't cross macro contexts while building the suggestion
Move `unnecessary_unsafety_doc` to `pedantic`
This lint was added in #9822. I like the idea, but also agree with #9986 as well. I think it should at least not be warn-by-default. This is one of these cases, where I'd like a group between pedantic and restriction. But I believe that users using `#![warn(clippy::pedantic)]` will know how to enable the lint if they disagree with it.
---
Since the lint is new:
changelog: none
r? `@flip1995` since I'd suggest back porting this, the original PR was merged 16 days ago.
Closes: #9986 (While it doesn't address everything, I believe that this is the best compromise)
Move `index_refutable_slice` to `pedantic`
During the creation, I out this lint into the nursery group to let it run in the wild before moving it to a commonly used group. This move never happened until now, though. It should be safe, as Clippy and I have been using it for months and there are no open issues for is :)
---
changelog: Move `index_refutable_slice` to `pedantic` (Now warn-by-default)
[#9975](https://github.com/rust-lang/rust-clippy/pull/9975)
Add allow-mixed-uninlined-format-args config
Implement `allow-mixed-uninlined-format-args` config param to change the behavior of the `uninlined_format_args` lint. Now it is a part of `style` per [Zulip chat](https://rust-lang.zulipchat.com/#narrow/stream/257328-clippy/topic/.60uninlined_format_args.60.20category), and won't propose inlining in case of a mixed usage, e.g. `print!("{} {}", var, 1+2)`. If the user sets `allow-mixed-uninlined-format-args` config param to `false`, the lint would behave like it did before -- proposing to inline args even in the mixed case.
---
changelog: [`uninlined_format_args`]: Added a new config `allow-mixed-uninlined-format-args` to allow the lint, if only some arguments can be inlined
[#9865](https://github.com/rust-lang/rust-clippy/pull/9865)
changelog: Moved [`uninlined_format_args`] to `style` (Now warn-by-default)
[#9865](https://github.com/rust-lang/rust-clippy/pull/9865)
Implement `allow-mixed-uninlined-format-args` config param to change the behavior of the `uninlined_format_args` lint. Now it is a part of `style`, and won't propose inlining in case of a mixed usage, e.g. `print!("{} {}", var, 1+2)`. If the user sets allow-mixed-uninlined-format-args config param to `false`, then it would behave like before, proposing to inline args even in the mixed case.
Separate lifetime ident from lifetime resolution in HIR
Drive-by: change how suggested generic args are computed.
Fixes https://github.com/rust-lang/rust/issues/103815
I recommend reviewing commit-by-commit.
Make rustc_target usable outside of rustc
I'm working on showing type size in rust-analyzer (https://github.com/rust-lang/rust-analyzer/pull/13490) and I currently copied rustc code inside rust-analyzer, which works, but is bad. With this change, I would become able to use `rustc_target` and `rustc_index` directly in r-a, reducing the amount of copy needed.
This PR contains some feature flag to put nightly features behind them to make crates buildable on the stable compiler + makes layout related types generic over index type + removes interning of nested layouts.
Avoid `GenFuture` shim when compiling async constructs
Previously, async constructs would be lowered to "normal" generators, with an additional `from_generator` / `GenFuture` shim in between to convert from `Generator` to `Future`.
The compiler will now special-case these generators internally so that async constructs will *directly* implement `Future` without the need to go through the `from_generator` / `GenFuture` shim.
The primary motivation for this change was hiding this implementation detail in stack traces and debuginfo, but it can in theory also help the optimizer as there is less abstractions to see through.
---
Given this demo code:
```rust
pub async fn a(arg: u32) -> Backtrace {
let bt = b().await;
let _arg = arg;
bt
}
pub async fn b() -> Backtrace {
Backtrace::force_capture()
}
```
I would get the following with the latest stable compiler (on Windows):
```
4: async_codegen:🅱️:async_fn$0
at .\src\lib.rs:10
5: core::future::from_generator::impl$1::poll<enum2$<async_codegen:🅱️:async_fn_env$0> >
at /rustc/897e37553bba8b42751c67658967889d11ecd120\library\core\src\future\mod.rs:91
6: async_codegen:🅰️:async_fn$0
at .\src\lib.rs:4
7: core::future::from_generator::impl$1::poll<enum2$<async_codegen:🅰️:async_fn_env$0> >
at /rustc/897e37553bba8b42751c67658967889d11ecd120\library\core\src\future\mod.rs:91
```
whereas now I get a much cleaner stack trace:
```
3: async_codegen:🅱️:async_fn$0
at .\src\lib.rs:10
4: async_codegen:🅰️:async_fn$0
at .\src\lib.rs:4
```
Previously, async constructs would be lowered to "normal" generators,
with an additional `from_generator` / `GenFuture` shim in between to
convert from `Generator` to `Future`.
The compiler will now special-case these generators internally so that
async constructs will *directly* implement `Future` without the need
to go through the `from_generator` / `GenFuture` shim.
The primary motivation for this change was hiding this implementation
detail in stack traces and debuginfo, but it can in theory also help
the optimizer as there is less abstractions to see through.
Add `clippy_utils::msrv::Msrv` to keep track of the current MSRV
changelog: Fix the scoping of the `#![clippy::msrv]` attribute
Fixes#6920
r? `@Jarcho`
Update Clippy
r? `@Manishearth`
Sorry for taking so long. There were so many blockers and so little time. This situation should be mitigated with #104007 in the future.
Fix#9771 (`unnecessary_to_owned` false positive)
Fixes#9771
In that issue's example(s), the lint tried to add a `&` to a value, which implicitly changed the type of a field to a reference. The fix is to add the reference to `receiver_ty` (the type of the receiver of the `to_owned`-like method), before passing `receiver_ty` to `can_change_type`. `can_change_type` properly rejects the modified `receiver_ty`.
cc: `@mikerite` just because I think he was the author of `can_change_type`.
changelog: fix `unnecessary_to_owned` false positive which implicitly tried to change the type of a field to a reference
Fix `redundant_closure_for_method_calls` suggestion
Fixes#7746. The issue turns out to be more general than raw pointers. The `redundant_closure_for_method_calls` lint produces incorrect suggestions when the method is associated with a type that must be enclosed in angle brackets or must be written with generic arguments substituted. For example:
```rust
fn main() {
// Clippy's suggestion: [T; N]::as_slice
// Correct suggestion: <[u8; 3]>::as_slice
let array_opt: Option<&[u8; 3]> = Some(&[4, 8, 7]);
array_opt.map(|a| a.as_slice());
// Clippy's suggestion: [T]::len
// Correct suggestion: <[u8]>::len
let slice_opt: Option<&[u8]> = Some(b"slice");
slice_opt.map(|s| s.len());
// Clippy's suggestion: *const T::is_null
// Correct suggestion: <*const usize>::is_null
let ptr_opt: Option<*const usize> = Some(&487);
ptr_opt.map(|p| p.is_null());
// Clippy's suggestion: dyn TestTrait::method_on_dyn
// Correct suggestion: <dyn TestTrait>::method_on_dyn
let test_struct = TestStruct {};
let dyn_opt: Option<&dyn TestTrait> = Some(&test_struct);
dyn_opt.map(|d| d.method_on_dyn());
}
// For the trait object example:
trait TestTrait {}
struct TestStruct {}
impl TestTrait for TestStruct {}
impl dyn TestTrait + '_ {
fn method_on_dyn(&self) -> bool {
false
}
}
```
The issue also affects references and tuples, though I had to patch the standard library with non-trait methods for those types to test that. Just in case, I also included handling for `!`, since it appeared to be possible to call methods on it with angle brackets. I just couldn't verify the resulting suggestion, since dead-code analysis eliminates the code first.
This is my first exposure to Rust compiler internals, so please let me know if I'm taking the wrong approach here!
changelog: [`redundant_closure_for_method_calls`]: add angle brackets and substitute generic arguments in suggestion when needed
Rollup of 11 pull requests
Successful merges:
- #103396 (Pin::new_unchecked: discuss pinning closure captures)
- #104416 (Fix using `include_bytes` in pattern position)
- #104557 (Add a test case for async dyn* traits)
- #104559 (Split `MacArgs` in two.)
- #104597 (Probe + better error messsage for `need_migrate_deref_output_trait_object`)
- #104656 (Move tests)
- #104657 (Do not check transmute if has non region infer)
- #104663 (rustdoc: factor out common button CSS)
- #104666 (Migrate alias search result to CSS variables)
- #104674 (Make negative_impl and negative_impl_exists take the right types)
- #104692 (Update test's cfg-if dependency to 1.0)
Failed merges:
r? `@ghost`
`@rustbot` modify labels: rollup
`MacArgs` is an enum with three variants: `Empty`, `Delimited`, and `Eq`. It's
used in two ways:
- For representing attribute macro arguments (e.g. in `AttrItem`), where all
three variants are used.
- For representing function-like macros (e.g. in `MacCall` and `MacroDef`),
where only the `Delimited` variant is used.
In other words, `MacArgs` is used in two quite different places due to them
having partial overlap. I find this makes the code hard to read. It also leads
to various unreachable code paths, and allows invalid values (such as
accidentally using `MacArgs::Empty` in a `MacCall`).
This commit splits `MacArgs` in two:
- `DelimArgs` is a new struct just for the "delimited arguments" case. It is
now used in `MacCall` and `MacroDef`.
- `AttrArgs` is a renaming of the old `MacArgs` enum for the attribute macro
case. Its `Delimited` variant now contains a `DelimArgs`.
Various other related things are renamed as well.
These changes make the code clearer, avoids several unreachable paths, and
disallows the invalid values.
Add new lint [`misnamed-getters`]
```
changelog: Add new lint [`misnamed-getters`]
```
Closes#9769
The current lint matches all methods with a body of just one expression under the form `(&mut?)? <expr>.field` where field doesn't match the name of the method but there is a field of the same type in `<expr>` that matches the name. This allows matching nested structs, for example for newtype wrappers. This may cast the net a bit too wide and cause false positives. I'll run [clippy_lint_tester](https://github.com/mikerite/clippy_lint_tester) on the top crates to see how frequently false positives happen.
There also may be room for improvement by checking that the replacement field would work taking into account implementations of `Deref` and `DerefMut` even if the types don't exactly match but I don't know yet how this could be done.
Add `PolyExistentialPredicate` type alias
Wrapping `ExistentialPredicate`s in a binder is very common, and this alias already exists for the `PolyExistential{TraitRef,Projection}` types.
[arithmetic-side-effects] Detect overflowing associated constants of integers
Triggers the negation of maximum unsigned integers using associated constants. Rustc already handles `-128i8` but doesn't handle `-i8::MAX`.
At the same time, allows stuff like `-1234`.
changelog: FP: [arithmetic-side-effects] Detect overflowing associated constants of integers
Keep original literal notation in suggestion
While I did some investigation of https://github.com/rust-lang/rust-clippy/issues/9866 (I couldn't reproduce it though) I found that `unused_rounding` formats as follows:
```rust
3.0_f64.round() // => 3.0f64
```
This PR makes them preserve as the original notation.
```rust
3.0_f64.round() // => 3.0_f64
```
changelog: Suggestion Enhancement: [`unused_rounding`]: The suggestion now preserves the original float literal notation
Improve spans for RPITIT object-safety errors
No reason why we can't point at the `impl Trait` that causes the object-safety violation.
Also [drive-by: Add is_async fn to hir::IsAsync](c4165f3a96), which touches clippy too.
Return multiple resolutions from `def_path_res`
Changes `def_path_res` to return all the resolutions matching the path rather than the first one (with a namespace hint that covered some cases). This would fix any issues that come up with multiple versions of the same crate being present as they all have the same crate name
It also adds resolution of `impl _ {}` items for local items, and removes struct field resolution as it didn't seem to be used anywhere
I tested it on a local crate and it worked for the multiple crate issue, but I couldn't come up with a test that worked well with `// aux-build`, maybe `// aux-crate` after https://github.com/rust-lang/rust/pull/103266 could work but I'm not sure on that either
changelog: [`disallowed_methods`], [`disallowed_types`], [`disallowed_macros`]: fix path resolution with multiple versions of the same crate
changelog: [`disallowed_methods`]: Resolve methods in `impl`s in the current crate
Rollup of 8 pull requests
Successful merges:
- #101162 (Migrate rustc_resolve to use SessionDiagnostic, part # 1)
- #103386 (Don't allow `CoerceUnsized` into `dyn*` (except for trait upcasting))
- #103405 (Detect incorrect chaining of if and if let conditions and recover)
- #103594 (Fix non-associativity of `Instant` math on `aarch64-apple-darwin` targets)
- #104006 (Add variant_name function to `LangItem`)
- #104494 (Migrate GUI test to use functions)
- #104516 (rustdoc: clean up sidebar width CSS)
- #104550 (fix a typo)
Failed merges:
- #104554 (Use `ErrorGuaranteed::unchecked_claim_error_was_emitted` less)
r? `@ghost`
`@rustbot` modify labels: rollup
Extend `needless_borrowed_reference` to structs and tuples, ignore _
changelog: [`needless_borrowed_reference`]: Lint struct and tuple patterns, and patterns containing `_`
Now lints patterns like
```rust
&(ref a, ref b)
&Tuple(ref a, ref b)
&Struct { ref a, ref b }
&(ref a, _)
```
Add variant_name function to `LangItem`
Clippy has an internal lint that checks for the usage of hardcoded def paths and suggests to replace them with a lang or diagnostic item, if possible. This was implemented with a hack, by getting all the variants of the `LangItem` enum and then index into it with the position of the `LangItem` in the `items` list. This is no longer possible, because the `items` list can't be accessed anymore.
Follow up to #103603
cc `@camsteffen`
r? `@oli-obk`
This is blocking the sync between Clippy and Rust. I'm not sure if this is the best solution here, or if I should add a method `items()` to `LanguageItems` and keep the code in Clippy unchanged.
Fix typo in `expect_used` and `unwrap_used` warning messages
"\`an Option\`" -> "an \`Option\`" and "\`a Result\`" -> "a \`Result\`".
changelog: fix typo in `expect_used` and `unwrap_used` warning messages
`never_loop`: don't emit AlwaysBreaks if it targets a block
ref: https://github.com/rust-lang/rust-clippy/pull/9837#issuecomment-1312788194
The previous fix (#9837) was too simple and ignored all break commands inside a labelled block, regardless of whether their destination was a labelled block or a loop. This fix tracks all the labelled blocks in scope to ensure that only breaks targeting loops are considered.
changelog: [`never_loop`]: prevent false negatives from `breaks` nested in labelled blocks
Convert predicates into Predicate in the Obligation constructor
instead of having almost all callers do that.
This reduces a bit of boilerplate, and also paves the way for my work towards https://github.com/rust-lang/compiler-team/issues/531 (as it makes it easier to accept both goals and clauses where right now it only accepts predicates).
Clippy has an internal lint that checks for the usage of hardcoded def
paths and suggests to replace them with a lang or diagnostic item, if
possible. This was implemented with a hack, by getting all the variants
of the `LangItem` enum and then index into it with the position of the
`LangItem` in the `items` list. This is no longer possible, because the
`items` list can't be accessed anymore.
Record `LocalDefId` in HIR nodes instead of a side table
This is part of an attempt to remove the `HirId -> LocalDefId` table from HIR.
This attempt is a prerequisite to creation of `LocalDefId` after HIR lowering (https://github.com/rust-lang/rust/pull/96840), by controlling how `def_id` information is accessed.
This first part adds the information to HIR nodes themselves instead of a table.
The second part is https://github.com/rust-lang/rust/pull/103902
The third part will be to make `hir::Visitor::visit_fn` take a `LocalDefId` as last parameter.
The fourth part will be to completely remove the side table.
When we run `cargo test` in `clippy_lints` directory, it will generate
`foo.txt` in the directory.
In order to avoid that, add `no_run` to rustdoc which contains
`File::create`.
Introduced an ignored_ids parameter.
Takes O(n^2) time in the worst case.
Can be changed to collect block ids in first phase,
and then filter with binary search in second.
Instead of `ast::Lit`.
Literal lowering now happens at two different times. Expression literals
are lowered when HIR is crated. Attribute literals are lowered during
parsing.
This commit changes the language very slightly. Some programs that used
to not compile now will compile. This is because some invalid literals
that are removed by `cfg` or attribute macros will no longer trigger
errors. See this comment for more details:
https://github.com/rust-lang/rust/pull/102944#issuecomment-1277476773
feat: lint unchecked subtraction of a 'Duration' from an 'Instant'
Hello all, I tried to tackle the open issue #9371 and this is what I came up with.
I have a difficulty currently - some tests are failing:
```
failures:
[ui] ui/manual_instant_elapsed.rs
```
The `manual_instant_elapsed` is failing because of `Instant::now() - duration` test, this now gets also picked by `unchecked_duration_subtraction` lint.
What is the correct way to proceed in this case? Simply update the `.stderr` file for `manual_instant_elapsed` lint?
changelog: [`unchecked_duration_subtraction`]: Add lint for unchecked subtraction of a `Duration` from an `Instant`.
fixes#9371
Make it clear that `or_fun_call` can be a false-positive
Also move it to nursery so that the false-positives can be dealt with.
CC #8574
changelog: [`or_fun_call`]: Mention false-positives, move to nursery.
Add `unnecessary_safety_doc` lint
changelog: [`unnecessary_safety_doc`]: Add `unnecessary_safety_doc` lint
fixes https://github.com/rust-lang/rust-clippy/issues/6880
This lint does not trigger for private functions, just like `missing_safety_docs`. Reason for that was implementation simplicity and because I figured asking first would make more sense, so if it should trigger for private functions as well let me know and I'll fix that up as well.
[`fn_params_excessive_bools`] Make it possible to allow the lint at the method level
changelog: FP: [`fn_params_excessive_bools`]: `#[allow]` now works on methods
fix https://github.com/rust-lang/rust-clippy/issues/9687
Tested without committing but `#[allow]`ing now works. Also rewrote the lint to be a late lint while at it :)
r? `@xFrednet`
In all the cases I've observed, it did not make the code clearer. Using
bools as integer is frowned upon in some languages, in others it's
simply not possible.
You can find comments on the original pull request #8131 that agree with
this point of view.
Fix `explicit_auto_deref` fp
fixes#9763fixes#9811
changelog: `explicit_auto_deref`: Don't lint when the target type is a projection with generic arguments
Update lint example for `collapsible_str_replace`
To fix this warning:
```
warning: the borrowed expression implements the required traits
--> src/fixes/quote_character.rs:16:43
|
16 | let hello = "hesuo worpd".replace(&['s', 'u', 'p'], "l");
| ^^^^^^^^^^^^^^^^ help: change this to: `['s', 'u', 'p']`
|
= note: `#[warn(clippy::needless_borrow)]` on by default
= help: for further information visit https://rust-lang.github.io/rust-clippy/master/index.html#needless_borrow
```
*Please write a short comment explaining your change (or "none" for internal only changes)*
changelog: none
Address issues 9739 and 9782
This PR fixes#9739 in the manner I suggested in https://github.com/rust-lang/rust-clippy/issues/9739#issuecomment-1296802376.
This PR also fixes the compilation failures in #9782 (but doesn't address `@e00E's` other objections).
Fixes#9739
r? `@Jarcho`
changelog: Fix two `needless_borrow` false positives, one involving borrows in `if`-`else`s, the other involving qualified function calls
Add `manual_is_ascii_check` lint
Addresses https://github.com/rust-lang/rust-clippy/issues/9290
This PR adds new lint `manual_is_ascii_check`, which detects comparison with ascii ranges using `matches!` macros.
As I mentioned as following in the Issue;
> Yes, that's true. we'll start small and then grow it.
> So I'll try to handle matches! macro with single range as suggested above.
However during writing first version, I was thinking that the changes to support alphabetic and digits will be small patch, so I made a single PR in hope review cost can be reduced.
changelog: add new lint [`manual_is_ascii_check`]
r? `@xFrednet`
Move needless_collect to nursery
*Please write a short comment explaining your change (or "none" for internal only changes)*
changelog: [`needless_collect`]: Move `needless_collect` to nursery (Now allow-by-default)
After chatting with a few folks, it seems like `needless_collect` is giving false positives pretty regularly (https://github.com/rust-lang/rust-clippy/issues?q=is%3Aissue+is%3Aopen+needless_collect). We're big supporters of clippy in Nushell, and it's one of the passes we require for CI, but we've had to disable this particular lint. Perhaps it should be moved to the nursery until it's improved?
(apologies if this isn't the right approach to disabling a lint by default. I tried to follow the idea I saw other PRs doing in the past)
Add allow-print-in-tests config
Add a config, allow-print-in-tests, that can be set in clippy.toml which allows the usage of `[e]print[ln]!` macros in tests.
Closes#9795
---
changelog: Enhancement: [print_stdout], [print_stderr]: Can now be enabled in test with the `allow-print-in-tests` config value
Changelog for Rust 1.65
Roses are red,
violets are blue,
another 6 weeks,
another changelog, yahoo!
This did not rhyme,
luckily, not a crime.
I want to say something smart,
but I am out of time.
---
Note for the reviewer. This PR is written, as if Rust was already released on 2022-11-03. Please review the changes and approve if you agree, but only merge it after the release. :)
---
changelog: none
Track where diagnostics were created.
This implements the `-Ztrack-diagnostics` flag, which uses `#[track_caller]` to track where diagnostics are created. It is meant as a debugging tool much like `-Ztreat-err-as-bug`.
For example, the following code...
```rust
struct A;
struct B;
fn main(){
let _: A = B;
}
```
...now emits the following error message:
```
error[E0308]: mismatched types
--> src\main.rs:5:16
|
5 | let _: A = B;
| - ^ expected struct `A`, found struct `B`
| |
| expected due to this
-Ztrack-diagnostics: created at compiler\rustc_infer\src\infer\error_reporting\mod.rs:2275:31
```
Improve `needless_lifetimes`
This PR makes the following improvements to `needless_lifetimes`.
* It fixes the following false negative, where `foo` is flagged but `bar` is not:
```rust
fn foo<'a>(x: &'a u8, y: &'_ u8) {}
fn bar<'a>(x: &'a u8, y: &'_ u8, z: &'_ u8) {}
```
* It flags more cases, generally. Previously, `needless_borrow` required *all* lifetimes to be used only once. With the changes, individual lifetimes are flagged for being used only once, even if not all lifetimes are.
* Finally, it tries to produce more clear error messages.
changelog: fix `needless_lifetimes` false negative involving functions with multiple unnamed lifetimes
changelog: in `needless_lifetimes`, flag individual lifetimes used only once, rather than require all lifetimes to be used only once
changelog: in `needless_lifetimes`, emit "replace with `'_`" warnings only when applicable, and point to a generic argument
