#![feature(plugin)] #![plugin(clippy)] #![deny(len_without_is_empty, len_zero)] #![allow(dead_code, unused)] pub struct PubOne; impl PubOne { pub fn len(self: &Self) -> isize { 1 } } impl PubOne { // A second impl for this struct - the error span shouldn't mention this pub fn irrelevant(self: &Self) -> bool { false } } // Identical to PubOne, but with an allow attribute on the impl complaining len pub struct PubAllowed; #[allow(len_without_is_empty)] impl PubAllowed { pub fn len(self: &Self) -> isize { 1 } } // No allow attribute on this impl block, but that doesn't matter - we only require one on the // impl containing len. impl PubAllowed { pub fn irrelevant(self: &Self) -> bool { false } } struct NotPubOne; impl NotPubOne { pub fn len(self: &Self) -> isize { // no error, len is pub but `NotPubOne` is not exported anyway 1 } } struct One; impl One { fn len(self: &Self) -> isize { // no error, len is private, see #1085 1 } } pub trait PubTraitsToo { fn len(self: &Self) -> isize; } impl PubTraitsToo for One { fn len(self: &Self) -> isize { 0 } } trait TraitsToo { fn len(self: &Self) -> isize; // no error, len is private, see #1085 } impl TraitsToo for One { fn len(self: &Self) -> isize { 0 } } struct HasPrivateIsEmpty; impl HasPrivateIsEmpty { pub fn len(self: &Self) -> isize { 1 } fn is_empty(self: &Self) -> bool { false } } pub struct HasIsEmpty; impl HasIsEmpty { pub fn len(self: &Self) -> isize { 1 } fn is_empty(self: &Self) -> bool { false } } struct Wither; pub trait WithIsEmpty { fn len(self: &Self) -> isize; fn is_empty(self: &Self) -> bool; } impl WithIsEmpty for Wither { fn len(self: &Self) -> isize { 1 } fn is_empty(self: &Self) -> bool { false } } pub struct HasWrongIsEmpty; impl HasWrongIsEmpty { pub fn len(self: &Self) -> isize { 1 } pub fn is_empty(self: &Self, x : u32) -> bool { false } } fn main() { let x = [1, 2]; if x.len() == 0 { println!("This should not happen!"); } if "".len() == 0 { } let y = One; if y.len() == 0 { //no error because One does not have .is_empty() println!("This should not happen either!"); } let z : &TraitsToo = &y; if z.len() > 0 { //no error, because TraitsToo has no .is_empty() method println!("Nor should this!"); } let has_is_empty = HasIsEmpty; if has_is_empty.len() == 0 { println!("Or this!"); } if has_is_empty.len() != 0 { println!("Or this!"); } if has_is_empty.len() > 0 { println!("Or this!"); } assert!(!has_is_empty.is_empty()); let with_is_empty: &WithIsEmpty = &Wither; if with_is_empty.len() == 0 { println!("Or this!"); } assert!(!with_is_empty.is_empty()); let has_wrong_is_empty = HasWrongIsEmpty; if has_wrong_is_empty.len() == 0 { //no error as HasWrongIsEmpty does not have .is_empty() println!("Or this!"); } } fn test_slice(b: &[u8]) { if b.len() != 0 { } }