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author | Daniel Baumann <daniel.baumann@progress-linux.org> | 2024-04-17 12:02:58 +0000 |
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committer | Daniel Baumann <daniel.baumann@progress-linux.org> | 2024-04-17 12:02:58 +0000 |
commit | 698f8c2f01ea549d77d7dc3338a12e04c11057b9 (patch) | |
tree | 173a775858bd501c378080a10dca74132f05bc50 /src/tools/clippy/tests/ui/let_unit.rs | |
parent | Initial commit. (diff) | |
download | rustc-698f8c2f01ea549d77d7dc3338a12e04c11057b9.tar.xz rustc-698f8c2f01ea549d77d7dc3338a12e04c11057b9.zip |
Adding upstream version 1.64.0+dfsg1.upstream/1.64.0+dfsg1
Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>
Diffstat (limited to 'src/tools/clippy/tests/ui/let_unit.rs')
-rw-r--r-- | src/tools/clippy/tests/ui/let_unit.rs | 177 |
1 files changed, 177 insertions, 0 deletions
diff --git a/src/tools/clippy/tests/ui/let_unit.rs b/src/tools/clippy/tests/ui/let_unit.rs new file mode 100644 index 000000000..c9bb2849f --- /dev/null +++ b/src/tools/clippy/tests/ui/let_unit.rs @@ -0,0 +1,177 @@ +// run-rustfix + +#![feature(lint_reasons)] +#![warn(clippy::let_unit_value)] +#![allow(unused, clippy::no_effect, clippy::needless_late_init, path_statements)] + +macro_rules! let_and_return { + ($n:expr) => {{ + let ret = $n; + }}; +} + +fn main() { + let _x = println!("x"); + let _y = 1; // this is fine + let _z = ((), 1); // this as well + if true { + let _a = (); + } + + consume_units_with_for_loop(); // should be fine as well + + multiline_sugg(); + + let_and_return!(()) // should be fine +} + +// Related to issue #1964 +fn consume_units_with_for_loop() { + // `for_let_unit` lint should not be triggered by consuming them using for loop. + let v = vec![(), (), ()]; + let mut count = 0; + for _ in v { + count += 1; + } + assert_eq!(count, 3); + + // Same for consuming from some other Iterator<Item = ()>. + let (tx, rx) = ::std::sync::mpsc::channel(); + tx.send(()).unwrap(); + drop(tx); + + count = 0; + for _ in rx.iter() { + count += 1; + } + assert_eq!(count, 1); +} + +fn multiline_sugg() { + let v: Vec<u8> = vec![2]; + + let _ = v + .into_iter() + .map(|i| i * 2) + .filter(|i| i % 2 == 0) + .map(|_| ()) + .next() + .unwrap(); +} + +#[derive(Copy, Clone)] +pub struct ContainsUnit(()); // should be fine + +fn _returns_generic() { + fn f<T>() -> T { + unimplemented!() + } + fn f2<T, U>(_: T) -> U { + unimplemented!() + } + fn f3<T>(x: T) -> T { + x + } + fn f5<T: Default>(x: bool) -> Option<T> { + x.then(|| T::default()) + } + + let _: () = f(); // Ok + let x: () = f(); // Lint. + + let _: () = f2(0i32); // Ok + let x: () = f2(0i32); // Lint. + + let _: () = f3(()); // Lint + let x: () = f3(()); // Lint + + // Should lint: + // fn f4<T>(mut x: Vec<T>) -> T { + // x.pop().unwrap() + // } + // let _: () = f4(vec![()]); + // let x: () = f4(vec![()]); + + // Ok + let _: () = { + let x = 5; + f2(x) + }; + + let _: () = if true { f() } else { f2(0) }; // Ok + let x: () = if true { f() } else { f2(0) }; // Lint + + // Ok + let _: () = match Some(0) { + None => f2(1), + Some(0) => f(), + Some(1) => f2(3), + Some(_) => f2('x'), + }; + + // Lint + let _: () = match Some(0) { + None => f2(1), + Some(0) => f(), + Some(1) => f2(3), + Some(_) => (), + }; + + let _: () = f5(true).unwrap(); + + #[allow(clippy::let_unit_value)] + { + let x = f(); + let y; + let z; + match 0 { + 0 => { + y = f(); + z = f(); + }, + 1 => { + println!("test"); + y = f(); + z = f3(()); + }, + _ => panic!(), + } + + let x1; + let x2; + if true { + x1 = f(); + x2 = x1; + } else { + x2 = f(); + x1 = x2; + } + + let opt; + match f5(true) { + Some(x) => opt = x, + None => panic!(), + }; + + #[warn(clippy::let_unit_value)] + { + let _: () = x; + let _: () = y; + let _: () = z; + let _: () = x1; + let _: () = x2; + let _: () = opt; + } + } + + let () = f(); +} + +fn attributes() { + fn f() {} + + #[allow(clippy::let_unit_value)] + let _ = f(); + #[expect(clippy::let_unit_value)] + let _ = f(); +} |