Fix `undocumented_unsafe_blocks` in closures
fixes#9114
changelog: Fix `undocumented_unsafe_blocks` not checking for comments before the start of a closure
`extra_unused_lifetimes` add FP test case emitting from derived attributes.
Add test to cover for #9014 which is fixed in #9037.
changelog: [`extra_unused_lifetimes`] Add FP test case emitting from derived attributes.
---
Seeing the FP from the test:
```sh
$ git revert -m 1 1d1ae10876
$ TESTNAME=extra_unused_lifetime cargo uitest
```
Add details about how significant drop in match scrutinees can cause deadlocks
Adds more details about how a significant drop in a match scrutinee can cause a deadlock and include link to documentation.
changelog: Add more details to significant drop lint to explicitly show how temporaries in match scrutinees can cause deadlocks.
Fix `#[expect]` for most clippy lints
This PR fixes most `#[expect]` - lint interactions listed in rust-lang/rust#97660. [My comment in the issue](https://github.com/rust-lang/rust/issues/97660#issuecomment-1147269504) shows the current progress (Once this is merged). I plan to work on `duplicate_mod` and `multiple_inherent_impl` and leave the rest for later. I feel like stabilizing the feature is more important than fixing the last few nits, which currently also don't work with `#[allow]`.
---
changelog: none
r? `@Jarcho`
cc: rust-lang/rust#97660
Add lint `explicit_auto_deref` take 2
fixes: #234fixes: #8367fixes: #8380
Still things to do:
* ~~This currently only lints `&*<expr>` when it doesn't trigger `needless_borrow`.~~
* ~~This requires a borrow after a deref to trigger. So `*<expr>` changing `&&T` to `&T` won't be caught.~~
* The `deref` and `deref_mut` trait methods aren't linted.
* Neither ~~field accesses~~, nor method receivers are linted.
* ~~This probably shouldn't lint reborrowing.~~
* Full slicing to deref should probably be handled here as well. e.g. `&vec[..]` when just `&vec` would do
changelog: new lint `explicit_auto_deref`
`trivially_copy_pass_by_ref` fixes
fixes#5953fixes#2961
The fix for #5953 is overly aggressive, but the suggestion is so bad that it's worth the false negatives. Basically three things together:
* It's not obviously wrong
* It compiles
* It may actually work when tested
changelog: Don't lint `trivially_copy_pass_by_ref` when unsafe pointers are used.
changelog: Better track lifetimes when linting `trivially_copy_pass_by_ref`.
add [`manual_find`] lint for function return case
part of the implementation discussed in #7143
changelog: add [`manual_find`] lint for function return case
feat(new lint): new lint `manual_retain`
close#8097
This PR is a new lint implementation.
This lint checks if the `retain` method is available.
Thank you in advance.
changelog: add new ``[`manual_retain`]`` lint
Suggest `pointer::cast` when possible in `transmute_ptr_to_ref`
fixes#8924
changelog: Suggest casting the pointer for any type containing lifetimes in `transmute_ptr_to_ref`.
changelog: Suggest `pointer::cast` when possible in `transmute_ptr_to_ref`.
enum_variant_names should ignore when all prefixes are _
close#9018
When Enum prefix is only an underscore, we should not issue warnings.
changelog: fix false positive in enum_variant_names
Lint `[single_match]` on `Option` matches
fixes#8928
changelog: did some cleanup of the logic for ``[`single_match`]`` and ``[`single_match_else`]`` which fixes the bug where `Option` matches were not linted unless a wildcard was used for one of the arms.
ignore item in `thread_local!` macro
close#8493
This PR ignores `thread_local` macro in `declare_interior_mutable_const`.
changelog: ignore `thread_local!` macro in `declare_interior_mutable_const`
add vec.capacity() to [`slow_vec_initialization`] detection
fix#8800
for example
```rust
let mut vec1 = Vec::with_capacity(len);
vec1.resize(vec1.capacity(), 0);
let mut vec2 = Vec::with_capacity(len);
vec2.extend(repeat(0).take(vec2.capacity()));
```
will trigger the lint
---
changelog: add `vec.capacity()` to [`slow_vec_initialization`] detection
Adds more details about how a significant drop in a match scrutinee can
cause a deadlock and include link to documentation. Emits messages
indicating temporaries with significant drops in arms of matches and
message about possible deadlocks/unexpected behavior.
changelog: Add more details to significant drop lint to explicitly show
how temporaries in match scrutinees can cause deadlocks/unexpected
behavior.
feat(fix): ignore `todo!` and `unimplemented!` in `if_same_then_else`
close: #8836
take over: #8853
This PR adds check `todo!` and `unimplemented!` in if_same_then_else.
( I thought `unimplemented` should not be checked as well as todo!.)
Thank you in advance.
changelog: ignore todo! and unimplemented! in if_same_then_else
r? `@Jarcho`
feat(lint): add default_iter_empty
close#8915
This PR adds `default_iter_empty` lint.
This lint checks `std::iter::Empty::default()` and replace with `std::iter::empty()`.
Thank you in advance.
---
changelog: add `default_instead_of_iter_empty` lint.
Update description in clippy_lints/src/default_iter_empty.rs
Co-authored-by: Fridtjof Stoldt <xFrednet@gmail.com>
Update clippy_lints/src/default_iter_empty.rs
Co-authored-by: Alex Macleod <alex@macleod.io>
Update clippy_lints/src/default_iter_empty.rs
Co-authored-by: Alex Macleod <alex@macleod.io>
renamed default_iter_empty to default_instead_of_iter_empty
Avoid duplicate messages
add tests for regression
rewrite 'Why is this bad?'
cargo dev fmt
delete default_iter_empty lint in renamed_lint.rs
rewrite a message in the suggestion
cargo dev update_lints --check
Hide irrelevant lines in suggestions to allow for suggestions that are far from each other to be shown
This is an attempt to fix suggestions one part of which is 6 lines or more far from the first. I've noticed "the problem" (of not showing some parts of the suggestion) here: https://github.com/rust-lang/rust/pull/97759#discussion_r889689230.
I'm not sure about the implementation (this big closure is just bad and makes already complicated code even more so), but I want to at least discuss the result.
Here is an example of how this changes the output:
Before:
```text
help: consider enclosing expression in a block
|
3 ~ 'l: { match () { () => break 'l,
4 |
5 |
6 |
7 |
8 |
...
```
After:
```text
help: consider enclosing expression in a block
|
3 ~ 'l: { match () { () => break 'l,
4 |
...
31|
32~ } };
|
```
r? `@estebank`
`@rustbot` label +A-diagnostics +A-suggestion-diagnostics
Rework `branches_sharing_code`
fixes#7378
This changes the lint from checking pairs of blocks, to checking all the blocks at the same time. As such there's almost none of the original code left.
changelog: Don't lint `branches_sharing_code` when using different binding names
Fix some `#[expect]` lint interaction
Fixing the first few lints that aren't caught by `#[expect]`. The root cause of these examples was, that the lint was emitted at the wrong location.
---
changelog: none
r? `@Jarcho`
cc: rust-lang/rust#97660
fix(lint): check const context
close: https://github.com/rust-lang/rust-clippy/issues/8898
This PR fixes a bug in checked_conversions.
Thank you in advance.
changelog: check const context in checked_conversions.
Remove migrate borrowck mode
Closes#58781Closes#43234
# Stabilization proposal
This PR proposes the stabilization of `#![feature(nll)]` and the removal of `-Z borrowck`. Current borrow checking behavior of item bodies is currently done by first infering regions *lexically* and reporting any errors during HIR type checking. If there *are* any errors, then MIR borrowck (NLL) never occurs. If there *aren't* any errors, then MIR borrowck happens and any errors there would be reported. This PR removes the lexical region check of item bodies entirely and only uses MIR borrowck. Because MIR borrowck could never *not* be run for a compiled program, this should not break any programs. It does, however, change diagnostics significantly and allows a slightly larger set of programs to compile.
Tracking issue: #43234
RFC: https://github.com/rust-lang/rfcs/blob/master/text/2094-nll.md
Version: 1.63 (2022-06-30 => beta, 2022-08-11 => stable).
## Motivation
Over time, the Rust borrow checker has become "smarter" and thus allowed more programs to compile. There have been three different implementations: AST borrowck, MIR borrowck, and polonius (well, in progress). Additionally, there is the "lexical region resolver", which (roughly) solves the constraints generated through HIR typeck. It is not a full borrow checker, but does emit some errors.
The AST borrowck was the original implementation of the borrow checker and was part of the initially stabilized Rust 1.0. In mid 2017, work began to implement the current MIR borrow checker and that effort ompleted by the end of 2017, for the most part. During 2018, efforts were made to migrate away from the AST borrow checker to the MIR borrow checker - eventually culminating into "migrate" mode - where HIR typeck with lexical region resolving following by MIR borrow checking - being active by default in the 2018 edition.
In early 2019, migrate mode was turned on by default in the 2015 edition as well, but with MIR borrowck errors emitted as warnings. By late 2019, these warnings were upgraded to full errors. This was followed by the complete removal of the AST borrow checker.
In the period since, various errors emitted by the MIR borrow checker have been improved to the point that they are mostly the same or better than those emitted by the lexical region resolver.
While there do remain some degradations in errors (tracked under the [NLL-diagnostics tag](https://github.com/rust-lang/rust/issues?q=is%3Aopen+is%3Aissue+label%3ANLL-diagnostics), those are sufficiently small and rare enough that increased flexibility of MIR borrow check-only is now a worthwhile tradeoff.
## What is stabilized
As said previously, this does not fundamentally change the landscape of accepted programs. However, there are a [few](https://github.com/rust-lang/rust/issues?q=is%3Aopen+is%3Aissue+label%3ANLL-fixed-by-NLL) cases where programs can compile under `feature(nll)`, but not otherwise.
There are two notable patterns that are "fixed" by this stabilization. First, the `scoped_threads` feature, which is a continutation of a pre-1.0 API, can sometimes emit a [weird lifetime error](https://github.com/rust-lang/rust/issues/95527) without NLL. Second, actually seen in the standard library. In the `Extend` impl for `HashMap`, there is an implied bound of `K: 'a` that is available with NLL on but not without - this is utilized in the impl.
As mentioned before, there are a large number of diagnostic differences. Most of them are better, but some are worse. None are serious or happen often enough to need to block this PR. The biggest change is the loss of error code for a number of lifetime errors in favor of more general "lifetime may not live long enough" error. While this may *seem* bad, the former error codes were just attempts to somewhat-arbitrarily bin together lifetime errors of the same type; however, on paper, they end up being roughly the same with roughly the same kinds of solutions.
## What isn't stabilized
This PR does not completely remove the lexical region resolver. In the future, it may be possible to remove that (while still keeping HIR typeck) or to remove it together with HIR typeck.
## Tests
Many test outputs get updated by this PR. However, there are number of tests specifically geared towards NLL under `src/test/ui/nll`
## History
* On 2017-07-14, [tracking issue opened](https://github.com/rust-lang/rust/issues/43234)
* On 2017-07-20, [initial empty MIR pass added](https://github.com/rust-lang/rust/pull/43271)
* On 2017-08-29, [RFC opened](https://github.com/rust-lang/rfcs/pull/2094)
* On 2017-11-16, [Integrate MIR type-checker with NLL](https://github.com/rust-lang/rust/pull/45825)
* On 2017-12-20, [NLL feature complete](https://github.com/rust-lang/rust/pull/46862)
* On 2018-07-07, [Don't run AST borrowck on mir mode](https://github.com/rust-lang/rust/pull/52083)
* On 2018-07-27, [Add migrate mode](https://github.com/rust-lang/rust/pull/52681)
* On 2019-04-22, [Enable migrate mode on 2015 edition](https://github.com/rust-lang/rust/pull/59114)
* On 2019-08-26, [Don't downgrade errors on 2015 edition](https://github.com/rust-lang/rust/pull/64221)
* On 2019-08-27, [Remove AST borrowck](https://github.com/rust-lang/rust/pull/64790)
* Don't lint on `.cloned().flatten()` when `T::Item` doesn't implement `IntoIterator`
* Reduce verbosity of lint message
* Narrow down the scope of the replacement range
improve [`for_loops_over_fallibles`] to detect the usage of iter, iter_mut and into_iterator
fix#6762
detects code like
```rust
for _ in option.iter() {
//..
}
```
changelog: Improve [`for_loops_over_fallibles`] to detect `for _ in option.iter() {}` or using `iter_mut()` or `into_iterator()`.
fix(manual_find_map and manual_filter_map): check clone method
close#8920
Added conditional branching when the clone method is used.
Thank you in advance.
---
changelog: check `clone()` and other variant preserving methods in [`manual_find_map`] and [`manual_filter_map`]
When setting suggestion for significant_drop_in_scrutinee, add suggestion for MoveAndClone for non-ref
When trying to set the current suggestion, if the type of the expression
is not a reference and it is not trivially pure clone copy, we should still
trigger and emit a lint message. Since this fix may require cloning an
expensive-to-clone type, do not attempt to offer a suggested fix.
This change means that matches generated from TryDesugar and AwaitDesugar
would normally trigger a lint, but they are out of scope for this lint,
so we will explicitly ignore matches with sources of TryDesugar or
AwaitDesugar.
changelog: Update for ``[`significant_drop_in_scrutinee`]`` to correctly
emit lint messages for cases where the type is not a reference *and*
not trivially pure clone copy.
changelog: [`significant_drop_in_scrutinee`]: No longer lint on Try `?`
and `await` desugared expressions.
remove `large_enum_variant` suggestion for `Copy` types
Replaces the (erroneous) suggestion on `large_enum_variant` for `Copy` types by a note. This fixes#8894.
---
changelog: none
Set correct `ParamEnv` for `derive_partial_eq_without_eq`
fixes#8867
changelog: Handle differing predicates applied by `#[derive(PartialEq)]` and `#[derive(Eq)]` in `derive_partial_eq_without_eq`
new lint: `borrow_deref_ref`
changelog: ``[`borrow_deref_ref`]``
Related pr: #6837#7577
`@Jarcho` Could you please give a review?
`cargo lintcheck` gives no false negative (but tested crates are out-of-date).
TODO:
1. Not sure the name. `deref_on_immutable_ref` or some others?
Fix `manual_range_contains` false negative with chains of `&&` and `||`
Fixes#8745
Since the precedence for `&&` is the same as itself the HIR for a chain of `&&` ends up with a right skewed tree like:
```
&&
/ \
&& c2
/ \
... c1
```
So only the leftmost `&&` was actually "fully" checked, the top level was just `c2` and `&&` so the `manual_range_contains` lint won't apply. This change makes it also check `c2` with `c1`.
There's a bit of a hacky solution in the [second commit](257f09776a) to check if the number of open/closing parens in the snippet match. This is to prevent a case like `((x % 2 == 0) || (x < 0)) || (x >= 10)` from offering a suggestion like `((x % 2 == 0) || !(0..10).contains(&x)` which now won't compile.
Any suggestions for that paren hack welcome, kinda new to working on this so not too sure about possible solutions :) it's weird because I don't know how else to check for parens in HIR considering they're removed when lowering AST.
changelog: Fix [`manual_range_contains`] false negative with chains of `&&` and `||`
Don't lint `useless_transmute` on types with erased regions
fixes#6356fixes#3340fixes#2906
This should get a proper fix at some point, but this at least gets the lint running on some types.
cc #5343
changelog: Don't lint `useless_transmute` on types with erased regions
`cast_abs_to_unsigned`: do not remove cast if it's required
Fixes#8873
If `iX` is not cast to `uX` then keep the cast rather than removing it
changelog: [`cast_abs_to_unsigned`]: do not remove cast if it's required
needless_late_init: fix ICE when all branches return the never type
Fixes#8911
When the assignment is done in a match guard or the if condition and all of the branches return the never type `assignment_suggestions` would return an empty `Vec` which caused the ICE. It now returns `None` in that scenario
Also moves some tests to the top of the file
changelog: ICE Fixes: [`needless_late_init`] #8911
