Co-authored-by: Takayuki Nakata <f.seasons017@gmail.com>

Update changelog for 1.52

I've underestimated the work that goes into this a bit, but it just shows that a lot has happened again in Clippy in 1.52 🙃.

[Rendered](https://github.com/xFrednet/rust-clippy/blob/changelog-1-52/CHANGELOG.md)

---

changelog: none

Fix bad suggestion when a reborrow might be required
Fix bad suggestion when the value being sliced is a macro call
Don't lint inside of a macro due to the previous context sensitive changes

Improve `redundant_slicing`

fixes: rust-lang#6968

changelog: Fix `redundant_slicing` suggestion when a reborrow might be required or when the value is from a macro call

Add MSRV options to `unnested_or_patterns`

changelog: [`unnested_or_patterns`] can now be configured with the `msrv` config/attribute.

Fixes rust-lang#6953

When the character next to `{}` is "shifted" (when mapping a byte index
in the format string to span) we should avoid shifting the span end
index, so first map the index of `}` to span, then bump the span,
instead of first mapping the next byte index to a span (which causes
bumping the end span too much).

Regression test added.

Fixes rust-lang#83344

Check the return type of `len`. Only integral types, or an `Option` or `Result` wrapping one.
Ensure the return type of `is_empty` matches. e.g. `Option<usize>` -> `Option<bool>`

`len_without_is_empty` improvements

fixes: rust-lang#6958
fixes: rust-lang#6972

changelog: Check the return type of `len`. Only integral types, or an `Option` or `Result` wrapping one.
changelog: Ensure the return type of `is_empty` matches. e.g. `Option<usize>` -> `Option<bool>`

Add missing lints to MSRV config doc

r? `@giraffate`

changelog: Add missing lints to MSRV config doc

Add function core::iter::zip

This makes it a little easier to `zip` iterators:

```rust
for (x, y) in zip(xs, ys) {}
// vs.
for (x, y) in xs.into_iter().zip(ys) {}
```

You can `zip(&mut xs, &ys)` for the conventional `iter_mut()` and
`iter()`, respectively. This can also support arbitrary nesting, where
it's easier to see the item layout than with arbitrary `zip` chains:

```rust
for ((x, y), z) in zip(zip(xs, ys), zs) {}
for (x, (y, z)) in zip(xs, zip(ys, zs)) {}
// vs.
for ((x, y), z) in xs.into_iter().zip(ys).zip(xz) {}
for (x, (y, z)) in xs.into_iter().zip((ys.into_iter().zip(xz)) {}
```

It may also format more nicely, especially when the first iterator is a
longer chain of methods -- for example:

```rust
    iter::zip(
        trait_ref.substs.types().skip(1),
        impl_trait_ref.substs.types().skip(1),
    )
    // vs.
    trait_ref
        .substs
        .types()
        .skip(1)
        .zip(impl_trait_ref.substs.types().skip(1))
```

This replaces the tuple-pair `IntoIterator` in rust-lang#78204.
There is prior art for the utility of this in [`itertools::zip`].

[`itertools::zip`]: https://docs.rs/itertools/0.10.0/itertools/fn.zip.html

look inside refs and detect if let &None = ...

Fixes rust-lang/rust-clippy#5396

changelog:  redundant_pattern_matching: look inside Refs to fix FNs with "if let &None = .. "

Found with https://github.com/est31/warnalyzer.

Dubious changes:
- Is anyone else using rustc_apfloat? I feel weird completely deleting
  x87 support.
- Maybe some of the dead code in rustc_data_structures, in case someone
  wants to use it in the future?
- Don't change rustc_serialize

  I plan to scrap most of the json module in the near future (see
  rust-lang/compiler-team#418) and fixing the
  tests needed more work than I expected.

TODO: check if any of the comments on the deleted code should be kept.

Check to see if the generic constraints are the same as if using derive

redundant_pattern_matching: look inside Refs

look inside refs and detect if let &None = ...

Fixes rust-lang/rust-clippy#5396

changelog:  redundant_pattern_matching: look inside Refs to fix FNs with "if let &None = .. "

Improve `expl_impl_clone_on_copy`

fixes: rust-lang#1254

changelog: Check to see if the generic constraints are the same as if using derive for `expl_impl_clone_on_copy`

Allow missing panics doc if the panics occur only when debug-assertions is specified

fixes rust-lang#6970

changelog: `missing_panics_doc`: Allow missing panics doc if the panics occur only when `debug-assertions` is specified.

Lint on `_.clone().method()` when method takes self by value
Set applicability correctly
Correct suggestion when the cloned value is a macro call. e.g. `m!(x).clone()`
Don't lint when not using the `Clone` trait

…msteffen

Use uppercase for MSRV

A follow-up of <https://github.com/rust-lang/rust-clippy/pull/6977/files#diff-dac623e7b9c58138761aa527bf5f026bf113cda5b22eea61e655b44dd113389e>

changelog: none

Organize functions into functions module

Ref: rust-lang#6680
Rearrange lints in `functions`.

changelog: none

Improve `clone_on_copy`

This also removes the `clone_on_copy_mut` test as the same thing is covered in the `clone_on_copy` test.

changelog: `copy_on_clone` lint on chained method calls taking self by value
changelog: `copy_on_clone` only lint when using the `Clone` trait
changelog: `copy_on_clone` correct suggestion when the cloned value is a macro call.

When the `to_*` method takes `&self` and it is a trait implementation,
we don't trigger the lint.

…teffen

Fix `manual_map` at the end of an if chain

changelog: Fix `manual_map` suggestion at the end of an if chain

…Manishearth

Add non_octal_unix_permissions lint

fixes rust-lang#6934

changelog: add new lint that checks for non-octal values used to set unix file permissions

result_unit_err: Fix typo

changelog: result_unit_err: fix typo in a diagnostic message

r? `@giraffate`
fixes rust-lang/rust-clippy#6990 (comment).

Fixes rust-lang#6984

Refactor types

r? `@flip1995`
This is the last PR to close rust-lang#6724 🎉
Also, this fixes rust-lang#6936.

changelog: `vec_box`: Fix FN in `const` or `static`
changelog: `linkedlist`: Fix FN in `const` or `static`
changelog: `option_option`: Fix FN in `const` or `static`

disable upper_case_acronyms for pub items - enum edition

Fixes rust-lang/rust-clippy#6803 (again... 😅  )

My previous fix did not work for enums because enum variants were checked separately in the `check_variant` function but it looks like we can't use that because we can't tell if the enum the variants belong to is declared as public or not (it always said `Inherited` for me)

I went and special-cased enums and iterated over all the variants "manually", but only, if the enums is not public.

---

changelog: fix upper_case_acronyms still firing on public enums (rust-lang#6803)

New Lint: needless_for_each

resolves: rust-lang#6543

changelog: Added pedantic lint: `needless_for_each`

Lint: filter(Option::is_some).map(Option::unwrap)

Fixes rust-lang#6061

*Please write a short comment explaining your change (or "none" for internal only changes)*
changelog:
* add new lint for filter(Option::is_some).map(Option::unwrap)

First Rust PR, so I'm sure I've violated some idioms. Happy to change anything.

I'm getting one test failure locally -- a stderr diff for `compile_test`. I'm having a hard time seeing how I could be causing it, so I'm tentatively opening this in the hopes that it's an artifact of my local setup against `rustc`. Hoping it can at least still be reviewed in the meantime.

I'm gathering that since this is a method lint, and `.filter(...).map(...)` is already checked, the means of implementation needs to be a little different, so I didn't exactly follow the setup boilerplate. My way of checking for method calls seems a little too direct (ie, "is the second element of the expression literally the path for `Option::is_some`?"), but it seems like that's how some other lints work, so I went with it. I'm assuming we're not concerned about, eg, closures that just end up equivalent to `Option::is_some` by eta reduction.

Destructure args in `methods`

changelog: none

This changes the main pattern in `methods` to match and destructure the method call args at the same time as the method name, and pass individual arg `Expr`s to the lint impls.

```rust
// before
["expect", ..] => expect::check(cx, expr, arg_lists[0]);
// after
("expect", [arg]) => expect::check(cx, expr, recv, arg);
```

This makes the code safer since there is no risk of out of bounds `args[n]` everywhere. There will be no more collecting `method_names`, `arg_lists`, `method_spans` as a separate step - everything comes out of the `match`es. Chained methods are parsed in a nested `match`. This makes the code more verbose in some ways, but IMO it is much easier to follow.

~Definitely should wait for rust-lang#6896. Just putting out the idea.~

lintcheck: warn if we get a bad exit status while running clippy

Right now we won't notice if a crate fails to build.
Print a warning message to indicate that there is a problem of some sort.
I'll still have to do more investigation on why this actually happens.

I suspect that the problem is that `clippy fix` might run  --all-targets  but when we download the crate source from crates.io, some path deps (used for internal tests etc...) are not available (which is usually not a problem because the internal tests are not needed when using the crate as a lib..?)

changelog: none

… clone is in use.

Internal `if_chain!` lints

changelog: none

We use `if_chain!` a lot. So this enforces some style rules around it, internal only.

Lints when...
* Nested `if`/`if_chain!` can be collapsed
* An `if_chain!` starts with `let` or ends with `let ..; then {..}`
* An `if_chain!` has only one `if`
* An `if_chain!` contains `if .. && ..;` that spans multiple lines

Don't lint `manual_map` in const functions

fixes: rust-lang#6967

changelog: Don't lint `manual_map` in const functions

…n_inside_trait_impls, r=phansch

wrong_self_convention: fix FP inside trait impl for `to_*` method taking `&self`

fixes rust-lang#6983
changelog: `wrong_self_convention`: fix FP inside trait impl for `to_*` method taking `&self`

Fix `redundant_clone` fp

fixes: rust-lang#5973
fixes: rust-lang#5595
fixes: rust-lang#6998

changelog: Fix `redundant_clone` fp  where the cloned value is modified while the clone is in use.

clippy_utils: fix needless parenthesis output from sugg::Sugg::maybe_par

changelog: clippy_utils: fix needless parenthesis output from `sugg::Sugg::maybe_par`

fixes: rust-lang#6767

…e loop body

Fix hidden variant suggestion on single variant

Fixes rust-lang#6984

changelog: Fix hidden variant suggestion on `match_wildcard_for_single_variants`

Remove paths from bind_instead_of_map

changelog: none

…arth

Improve needless_collect output

changelog: Improve needless_collect output

Fixes rust-lang#6908
Partially addresses rust-lang#6164