Easier readability for `needless_late_init` message
Closes#8530
Updated the lint to use a `MultiSpan`, showing where the `let` statement was first used and where the initialisation statement was done, as in the format described, for easier readability.
Was wondering why, when pushing the span label for the initialisation statement, that sometimes the prior statement above the initialisation statement gets pulled into the output as well - any insight is appreciated!
---
changelog: [`needless_late_init`]: Now shows the `let` statement where it was first initialized
[FP] identity_op in front of if
fix#8724
changelog: FP: [`identity_op`]: is now allowed in front of if statements, blocks and other expressions where the suggestion would be invalid.
Resolved simular problems with blocks, mathces, and loops.
identity_op always does NOT suggest reducing `0 + if b { 1 } else { 2 } + 3` into `if b { 1 } else { 2 } + 3` even in the case that the expression is in `f(expr)` or `let x = expr;` for now.
Only crate root def-ids don't have a parent, and in majority of cases the argument of `DefIdTree::parent` cannot be a crate root.
So we now panic by default in `parent` and introduce a new non-panicing function `opt_parent` for cases where the argument can be a crate root.
Same applies to `local_parent`/`opt_local_parent`.
Change `span_suggestion` (and variants) to take `impl ToString` rather
than `String` for the suggested code, as this simplifies the
requirements on the diagnostic derive.
Signed-off-by: David Wood <david.wood@huawei.com>
ignore `redundant_pub_crate` in `useless_attribute`
changelog: [`useless_attribute`] no longer lints [`redundant_pub_crate`]
As mentioned in https://github.com/rust-lang/rust-clippy/issues/8732#issuecomment-1106489634
> And it turns out I can't even explicitly allow it at the usage site, because then `clippy::useless_attribute` fires (which would also be a FP?), which is deny-by-default.
>
> Though it does work if I then allow `clippy::useless_attribute`. 😂
>
> ```rust
> #[allow(clippy::useless_attribute)]
> #[allow(clippy::redundant_pub_crate)]
> pub(crate) use bit;
> ```
>
> The originally-reported warning now no longer occurs.
`needless_late_init`: ignore `if let`, `let mut` and significant drops
No longer lints `if let`, personal taste on this one is pretty split, so it probably shouldn't be warning by default. Fixes#8613
```rust
let x = if let Some(n) = y {
n
} else {
1
}
```
No longer lints `let mut`, things like the following are not uncommon and look fine as they are
b169c16d86/src/sixty_four.rs (L88-L93)
Avoids changing the drop order in an observable way, where the type of `x` has a drop with side effects and something between `x` and the first use also does, e.g.
48cc6cb791/tests/test_api.rs (L159-L167)
The implementation of `type_needs_ordered_drop_inner` was changed a bit, it now uses `Ty::has_significant_drop` and reordered the ifs to check diagnostic name before checking the implicit drop impl
changelog: [`needless_late_init`]: No longer lints `if let` statements, `let mut` bindings and no longer significantly changes drop order
mistyped_literal_suffix: improve integer suggestions, avoid wrong float suggestions
This PR fixes 2 things:
- The known problem that integer types are always suggested as signed, by suggesting an unsigned suffix for literals that wouldnt fit in the signed type, and ignores any literals too big for the corresponding unsigned type too.
- The lint would only look at the integer part of any floating point literals without an exponent, this causing #6129. This just ignores those literals.
Examples:
```rust
let _ = 2_32; // still 2_i32
let _ = 234_8; // would now suggest 234_u8
// these are now ignored
let _ = 500_8;
let _ = 123_32.123;
```
changelog: suggest correct integer types in [`mistyped_literal_suffix`], ignore float literals without an exponent
fixes#6129
Previously this lint would only look at the integer part of floating
point literals without an exponent, giving wrong suggestions like:
```
|
8 | let _ = 123_32.123;
| ^^^^^^^^^^ help: did you mean to write: `123.123_f32`
|
```
Instead, it now ignores these literals.
Fixes#6129
Instead of just always suggesting signed suffixes regardless of size
of the value, it now suggests an unsigned suffix when the value wouldn't
fit into the corresponding signed type, and ignores the literal entirely
if it is too big for the unsigned type as well.
wrong_self_convention allows `is_*` to take `&mut self`
fix#8480 and #8513
Allowing `is_*` to take `&self` or none is too restrictive.
changelog: FPs: [`wrong_self_convention`] now allows `&mut self` and no self as arguments for `is_*` methods
`manual_split_once`: lint manual iteration of `SplitN`
changelog: `manual_split_once`: lint manual iteration of `SplitN`
Now lints:
```rust
let mut iter = "a.b.c".splitn(2, '.');
let first = iter.next().unwrap();
let second = iter.next().unwrap();
let mut iter = "a.b.c".splitn(2, '.');
let first = iter.next()?;
let second = iter.next()?;
let mut iter = "a.b.c".rsplitn(2, '.');
let first = iter.next().unwrap();
let second = iter.next().unwrap();
let mut iter = "a.b.c".rsplitn(2, '.');
let first = iter.next()?;
let second = iter.next()?;
```
It suggests (minus leftover whitespace):
```rust
let (first, second) = "a.b.c".split_once('.').unwrap();
let (first, second) = "a.b.c".split_once('.')?;
let (second, first) = "a.b.c".rsplit_once('.').unwrap();
let (second, first) = "a.b.c".rsplit_once('.')?;
```
Currently only lints if the statements are next to each other, as detecting the various kinds of shadowing was tricky, so the following won't lint
```rust
let mut iter = "a.b.c".splitn(2, '.');
let something_else = 1;
let first = iter.next()?;
let second = iter.next()?;
```
