fix 5707
changelog: ``[`redundant_clone`]``, fix#5707
# Root problem of #5707 :
```
&2:&mut HashMap = &mut _4;
&3:&str = & _5;
_1 = HashMap::insert(move _2,move _3, _);
```
generate PossibleBorrower(_2,_1) and PossibleBorrower(_3,_1).
However, it misses PossibleBorrower(_3,_2).
# My solution to #5707 :
When meet a function call, we should:
1. build PossibleBorrower between borrow parameters and return value (currently)
2. build PossibleBorrower between immutable borrow parameters and mutable borrow parameters (*add*)
3. build PossibleBorrower inside mutable borrow parameters (*add*)
For example:
```
_2: &mut _22;
_3: &mut _;
_4: & _;
_5: & _;
_1 = call(move _2, move _3, move _4, move _5);
```
we need to build
1. return value with parameter(current implementataion)
PossibleBorrower(_2,_1)
PossibleBorrower(_3,_1)
PossibleBorrower(_4,_1)
PossibleBorrower(_5,_1)
2. between mutable borrow and immutable borrow
PossibleBorrower(_4,_2)
PossibleBorrower(_5,_2)
PossibleBorrower(_4,_3)
PossibleBorrower(_5,_3)
3. between mutable borrow and mutable borrow
PossibleBorrower(_3,_2)
PossibleBorrower(_2,_3)
But that's not enough.
Modification to _2 actually apply to _22.
So I write a `PossibleBorrowed` visitor, which tracks (borrower => possible borrowed) relation.
For example (_2 => _22).
However, a lot of problems exist here.
## Known Problems:
1. not sure all `&mut`'s origin are collected.
I'm not sure how to deal with `&mut` when meet a function call, so I didn't do it currently.
Also, my implement is not flow sensitive, so it's not accurate.
```
foo(_2:&mut _, _3: &_)
```
This pr doesn't count _3 as origin of _2.
2. introduce false negative
`foo(_2, _3)` will emit PossibleBorrower(_3,_2) in this pr, but _3 and _2 may not have relation.
Clippy may feel that _3 is still in use because of _2, but actually, _3 is on longer needed and can be moved.
## Insight
The key problem is determine where every `&mut` come from accurately.
I think Polonius is an elegant solution to it. Polonius is flow sensitive and accurate.
But I'm uncertain about whether we can import Polonius in rust-clippy currently.
This pr actually is part of Polonius' functionality, I think.
# TODO
1. `cargo test` can't pass yet due to similar variable name
Refactor `format_args!` expansion parsing
Introduces `FormatExpn::parse` and `FormatArgsExpn::parse`. Motivated by rust-lang/rust#83302, so I only have to change Clippy in one place. Fixed an FP along the way.
I also allowed `needless_bool` in macros because I often want to do `if_chain! { .. then { true } else { false } }`.
changelog: Fix false positive in `useless_format` when some text is appended or prepended to a single string with some useless formatting params
changelog: Allow `needless_bool` in macros
Remove lints_enabled
r? `@camsteffen`
cc https://github.com/rust-lang/rust-clippy/pull/7448#issuecomment-876497862
I haven't added a variant with `last_node_with_lint_attrs` yet, since I didn't see a usecase for this. Also this field is not documented, so I'm wondering how it behaves with command line lints and so on.
changelog: none
Rename run_lints -> lints_enabled
Just a quick rename of a utilities function. `run_lints` kinda suggested that the lints were run by this function. But the only thing this function does is to check if the lints are enabled in the context of the `hir_id`
changelog: none
Fix false-positive `assert` in `panic`
This PR fixes a false-positive in `clippy::panic` when using the `assert` macro with its optional message parameter.
Fixes: #7433
changelog: `panic_unimplemented.rs`: added condition to exclude `assert` macro, similar to `debug_assert`
changelog: `panicking_macros.rs`: relevant tests to check for `assert` usage.
Add new lint: `strlen_on_c_strings`
~~This is WIP, linting in case of `CString` has been added, but for `CStr`, its diagnostic item needs to be available for clippy.
[PR that adds diagnostic item for CStr on rust repo](https://github.com/rust-lang/rust/pull/85439).~~
Ready for the review. Please take a look.
fixes#7145
changelog: Add new lint: `strlen_on_c_strings`, that lints on `libc::strlen(some_cstring.as_ptr())`
Downgrade nonstandard_macro_braces to nursery
Due to the large number of crates impacted by #7422, I don't think this lint can be enabled by default right now until the false positive is fixed.
---
changelog: remove [`nonstandard_macro_braces`] from default set of enabled lints
Don't suggest doc(hidden) or unstable variants in wildcard lint
Clippy's wildcard lint would suggest doc(hidden) and unstable variants for non_exhaustive enums, even though those aren't part of the public interface (yet) and should only be matched on using a `_`, just like potential future additions to the enum. There was already some logic to exclude a *single* doc(hidden) variant. This extends that to all hidden variants, and also hides `#[unstable]` variants.
See https://github.com/rust-lang/rust/pull/85746#issuecomment-868886893
This PR includes https://github.com/rust-lang/rust-clippy/pull/7406 as the first commit.
Here's the diff that this PR adds on top of that PR: https://github.com/m-ou-se/rust-clippy/compare/std-errorkind...m-ou-se:doc-hidden-variants
---
*Please write a short comment explaining your change (or "none" for internal only changes)*
changelog: No longer suggest unstable and doc(hidden) variants in wildcard lint. wildcard_enum_match_arm, match_wildcard_for_single_variants
This fixes a bug where match_wildcard_for_single_variants produced a
bad suggestion where besides the missing variant, one or more hidden
variants were left.
This also adds tests to the ui-tests match_wildcard_for_single_variants
and wildcard_enum_match_arm to make sure that the correct suggestion is
produced.
New lint: `disallowed_script_idents`
This PR implements a new lint to restrict locales that can be used in the code,
as proposed in #7376.
Current concerns / unresolved questions:
- ~~Mixed usage of `script` (as a Unicode term) and `locale` (as something that is easier to understand for the broad audience). I'm not sure whether these terms are fully interchangeable and whether in the current form it is more confusing than helpful.~~ `script` is now used everywhere.
- ~~Having to mostly copy-paste `AllowedScript`. Probably it's not a big problem, as the list of scripts is standardized and is unlikely to change, and even if we'd stick to the `unicode_script::Script`, we'll still have to implement custom deserialization, and I don't think that it will be shorter in terms of the amount of LoC.~~ `unicode::Script` is used together with a filtering deserialize function.
- Should we stick to the list of "recommended scripts" from [UAX #31](http://www.unicode.org/reports/tr31/#Table_Recommended_Scripts) in the configuration?
*Please write a short comment explaining your change (or "none" for internal only changes)*
changelog: ``[`disallowed_script_idents`]``
r? `@Manishearth`
Improve lint message for match-same-arms lint
fixes#7331
Follow-up to #7377
This PR improves the lint message for `match-same-arms` lint and adds `todo!(..)` example to the lint docs.
*Please write a short comment explaining your change (or "none" for internal only changes)*
changelog: None
