Matthias Krüger 4af1c31fcf Rollup merge of #125156 - zachs18:for_loops_over_fallibles_behind_refs, r=Nilstrieb ... Expand `for_loops_over_fallibles` lint to lint on fallibles behind references. Extends the scope of the (warn-by-default) lint `for_loops_over_fallibles` from just `for _ in x` where `x: Option<_>/Result<_, _>` to also cover `x: &(mut) Option<_>/Result<_>` ```rs fn main() { // Current lints for _ in Some(42) {} for _ in Ok::<_, i32>(42) {} // New lints for _ in &Some(42) {} for _ in &mut Some(42) {} for _ in &Ok::<_, i32>(42) {} for _ in &mut Ok::<_, i32>(42) {} // Should not lint for _ in Some(42).into_iter() {} for _ in Some(42).iter() {} for _ in Some(42).iter_mut() {} for _ in Ok::<_, i32>(42).into_iter() {} for _ in Ok::<_, i32>(42).iter() {} for _ in Ok::<_, i32>(42).iter_mut() {} } ``` <details><summary><code>cargo build</code> diff</summary> ```diff diff --git a/old.out b/new.out index 84215aa..ca195a7 100644 --- a/old.out +++ b/new.out `@@` -1,33 +1,93 `@@` warning: for loop over an `Option`. This is more readably written as an `if let` statement --> src/main.rs:3:14 | 3 | for _ in Some(42) {} | ^^^^^^^^ | = note: `#[warn(for_loops_over_fallibles)]` on by default help: to check pattern in a loop use `while let` | 3 | while let Some(_) = Some(42) {} | ~~~~~~~~~~~~~~~ ~~~ help: consider using `if let` to clear intent | 3 | if let Some(_) = Some(42) {} | ~~~~~~~~~~~~ ~~~ warning: for loop over a `Result`. This is more readably written as an `if let` statement --> src/main.rs:4:14 | 4 | for _ in Ok::<_, i32>(42) {} | ^^^^^^^^^^^^^^^^ | help: to check pattern in a loop use `while let` | 4 | while let Ok(_) = Ok::<_, i32>(42) {} | ~~~~~~~~~~~~~ ~~~ help: consider using `if let` to clear intent | 4 | if let Ok(_) = Ok::<_, i32>(42) {} | ~~~~~~~~~~ ~~~ -warning: `for-loops-over-fallibles` (bin "for-loops-over-fallibles") generated 2 warnings - Finished `dev` profile [unoptimized + debuginfo] target(s) in 0.04s +warning: for loop over a `&Option`. This is more readably written as an `if let` statement + --> src/main.rs:7:14 + | +7 | for _ in &Some(42) {} + | ^^^^^^^^^ + | +help: to check pattern in a loop use `while let` + | +7 | while let Some(_) = &Some(42) {} + | ~~~~~~~~~~~~~~~ ~~~ +help: consider using `if let` to clear intent + | +7 | if let Some(_) = &Some(42) {} + | ~~~~~~~~~~~~ ~~~ + +warning: for loop over a `&mut Option`. This is more readably written as an `if let` statement + --> src/main.rs:8:14 + | +8 | for _ in &mut Some(42) {} + | ^^^^^^^^^^^^^ + | +help: to check pattern in a loop use `while let` + | +8 | while let Some(_) = &mut Some(42) {} + | ~~~~~~~~~~~~~~~ ~~~ +help: consider using `if let` to clear intent + | +8 | if let Some(_) = &mut Some(42) {} + | ~~~~~~~~~~~~ ~~~ + +warning: for loop over a `&Result`. This is more readably written as an `if let` statement + --> src/main.rs:9:14 + | +9 | for _ in &Ok::<_, i32>(42) {} + | ^^^^^^^^^^^^^^^^^ + | +help: to check pattern in a loop use `while let` + | +9 | while let Ok(_) = &Ok::<_, i32>(42) {} + | ~~~~~~~~~~~~~ ~~~ +help: consider using `if let` to clear intent + | +9 | if let Ok(_) = &Ok::<_, i32>(42) {} + | ~~~~~~~~~~ ~~~ + +warning: for loop over a `&mut Result`. This is more readably written as an `if let` statement + --> src/main.rs:10:14 + | +10 | for _ in &mut Ok::<_, i32>(42) {} + | ^^^^^^^^^^^^^^^^^^^^^ + | +help: to check pattern in a loop use `while let` + | +10 | while let Ok(_) = &mut Ok::<_, i32>(42) {} + | ~~~~~~~~~~~~~ ~~~ +help: consider using `if let` to clear intent + | +10 | if let Ok(_) = &mut Ok::<_, i32>(42) {} + | ~~~~~~~~~~ ~~~ + +warning: `for-loops-over-fallibles` (bin "for-loops-over-fallibles") generated 6 warnings + Finished `dev` profile [unoptimized + debuginfo] target(s) in 0.02s ``` </details> ----- Question: * ~~Currently, the article `an` is used for `&Option`, and `&mut Option` in the lint diagnostic, since that's what `Option` uses. Is this okay or should it be changed? (likewise, `a` is used for `&Result` and `&mut Result`)~~ The article `a` is used for `&Option`, `&mut Option`, `&Result`, `&mut Result` and (as before) `Result`. Only `Option` uses `an` (as before). `@rustbot` label +A-lint		2024-05-23 07:41:17 +02:00
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src	Rollup merge of #125156 - zachs18:for_loops_over_fallibles_behind_refs, r=Nilstrieb	2024-05-23 07:41:17 +02:00
Cargo.toml	Remove useless smallvec dependency in rustc_lint::non_local_def	2024-03-07 07:54:15 +01:00
messages.ftl	Rollup merge of #125156 - zachs18:for_loops_over_fallibles_behind_refs, r=Nilstrieb	2024-05-23 07:41:17 +02:00