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Rollup merge of #121364 - Urgau:unary_precedence, r=compiler-errors

Implement lint against ambiguous negative literals

This PR implements a lint against ambiguous negative literals with a literal and method calls right after it.

## `ambiguous_negative_literals`

(deny-by-default)

The `ambiguous_negative_literals` lint checks for cases that are confusing between a negative literal and a negation that's not part of the literal.

### Example

```rust,compile_fail
-1i32.abs(); // equals -1, while `(-1i32).abs()` equals 1
```

### Explanation

Method calls take precedence over unary precedence. Setting the precedence explicitly makes the code clearer and avoid potential bugs.

<details>
<summary>Old proposed lint</summary>

## `ambiguous_unary_precedence`

(deny-by-default)

The `ambiguous_unary_precedence` lint checks for use the negative unary operator with a literal and method calls.

### Example

```rust
-1i32.abs(); // equals -1, while `(-1i32).abs()` equals 1
```

### Explanation

Unary operations take precedence on binary operations and method calls take precedence over unary precedence. Setting the precedence explicitly makes the code clearer and avoid potential bugs.

</details>

-----

Note: This is a strip down version of https://github.com/rust-lang/rust/pull/117161, without the binary op precedence.

Fixes https://github.com/rust-lang/rust/issues/117155
`@rustbot` labels +I-lang-nominated
cc `@scottmcm`
r? compiler
This commit is contained in:
Matthias Krüger 2024-07-25 16:48:17 +02:00 committed by GitHub
commit ae71900ef6
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12 changed files with 325 additions and 156 deletions

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@ -73,6 +73,7 @@ mod noop_method_call;
mod opaque_hidden_inferred_bound;
mod pass_by_value;
mod passes;
mod precedence;
mod ptr_nulls;
mod redundant_semicolon;
mod reference_casting;
@ -111,6 +112,7 @@ use nonstandard_style::*;
use noop_method_call::*;
use opaque_hidden_inferred_bound::*;
use pass_by_value::*;
use precedence::*;
use ptr_nulls::*;
use redundant_semicolon::*;
use reference_casting::*;
@ -174,6 +176,7 @@ early_lint_methods!(
RedundantSemicolons: RedundantSemicolons,
UnusedDocComment: UnusedDocComment,
Expr2024: Expr2024,
Precedence: Precedence,
]
]
);