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)
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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 :)
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changelog: none
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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
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`
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. :)
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changelog: none
Add lint for confusing use of `^` instead of `.pow`
fixes#4205
Adds a lint named [`confusing_xor_and_pow`], it warns the user when `a ^ b` is used as the `.pow()` function, it doesn't warn for Hex, Binary... etc.
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changelog: New lint: [`confusing_xor_and_pow`]
add new lint `seek_to_start_instead_of_rewind `
changelog: `seek_to_start_instead_of_rewind`: new lint to suggest using `rewind` instead of `seek` to start
Resolve#8600
Add `unused_format_specs` lint
Currently catches two cases:
An empty precision specifier:
```rust
// the same as {}
println!("{:.}", x);
```
And using formatting specs on `format_args!()`:
```rust
// prints `x.`, not `x .`
println("{:5}.", format_args!("x"));
```
changelog: new lint: [`unused_format_specs`]
Add `manual_filter` lint for `Option`
Share much of its implementation with `manual_map` and should greatly benefit from its previous feedback.
I'm sure it's possible to even more refactor both and would gladly take input on that as well as any clippy idiomatic usage, since this is my first lint addition.
I've added the lint to the complexity section for now, I don't know if every new lint needs to go in nursery first.
The matching could be expanded to more than `Some(<value>)` to lint on arbitrary struct matching inside the `Some` but I've left it like it was for `manual_map` for now. `needless_match::pat_same_as_expr` provides a more generic match example.
close https://github.com/rust-lang/rust-clippy/issues/8822
changelog: Add lint [`manual_filter`] for `Option`
This lint detects calls to a `&self`-taking `as_ptr` method, where
the result is then immediately cast to a `*mut T`. Code like this
is probably invalid, as that pointer will not have write permissions,
and `*mut T` is usually used to write through.
