#![feature(plugin)] #![plugin(clippy)] #![deny(while_let_loop, empty_loop, while_let_on_iterator)] #![allow(dead_code, unused, cyclomatic_complexity)] fn main() { let y = Some(true); loop { if let Some(_x) = y { let _v = 1; } else { break } } loop { // no error, break is not in else clause if let Some(_x) = y { let _v = 1; } break; } loop { match y { Some(_x) => true, None => break }; } loop { let x = match y { Some(x) => x, None => break }; let _x = x; let _str = "foo"; } loop { let x = match y { Some(x) => x, None => break, }; { let _a = "bar"; }; { let _b = "foobar"; } } loop { // no error, else branch does something other than break match y { Some(_x) => true, _ => { let _z = 1; break; } }; } while let Some(x) = y { // no error, obviously println!("{}", x); } // #675, this used to have a wrong suggestion loop { let (e, l) = match "".split_whitespace().next() { Some(word) => (word.is_empty(), word.len()), None => break }; let _ = (e, l); } let mut iter = 1..20; while let Option::Some(x) = iter.next() { println!("{}", x); } let mut iter = 1..20; while let Some(x) = iter.next() { println!("{}", x); } let mut iter = 1..20; while let Some(_) = iter.next() {} let mut iter = 1..20; while let None = iter.next() {} // this is fine (if nonsensical) let mut iter = 1..20; if let Some(x) = iter.next() { // also fine println!("{}", x) } // the following shouldn't warn because it can't be written with a for loop let mut iter = 1u32..20; while let Some(x) = iter.next() { println!("next: {:?}", iter.next()) } // neither can this let mut iter = 1u32..20; while let Some(x) = iter.next() { println!("next: {:?}", iter.next()); } // or this let mut iter = 1u32..20; while let Some(x) = iter.next() {break;} println!("Remaining iter {:?}", iter); // or this let mut iter = 1u32..20; while let Some(x) = iter.next() { iter = 1..20; } } // regression test (#360) // this should not panic // it's okay if further iterations of the lint // cause this function to trigger it fn no_panic(slice: &[T]) { let mut iter = slice.iter(); loop { let _ = match iter.next() { Some(ele) => ele, None => break }; loop {} } } fn issue1017() { let r: Result = Ok(42); let mut len = 1337; loop { match r { Err(_) => len = 0, Ok(length) => { len = length; break } } } } // Issue #1188 fn refutable() { let a = [42, 1337]; let mut b = a.iter(); // consume all the 42s while let Some(&42) = b.next() { } let a = [(1, 2, 3)]; let mut b = a.iter(); while let Some(&(1, 2, 3)) = b.next() { } let a = [Some(42)]; let mut b = a.iter(); while let Some(&None) = b.next() { } /* This gives “refutable pattern in `for` loop binding: `&_` not covered” for &42 in b {} for &(1, 2, 3) in b {} for &Option::None in b.next() {} // */ }