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|
//@run-rustfix
#![warn(clippy::len_zero)]
#![allow(dead_code, unused, clippy::len_without_is_empty)]
extern crate core;
use core::ops::Deref;
pub struct One;
struct Wither;
trait TraitsToo {
fn len(&self) -> isize;
// No error; `len` is private; see issue #1085.
}
impl TraitsToo for One {
fn len(&self) -> isize {
0
}
}
pub struct HasIsEmpty;
impl HasIsEmpty {
pub fn len(&self) -> isize {
1
}
fn is_empty(&self) -> bool {
false
}
}
pub struct HasWrongIsEmpty;
impl HasWrongIsEmpty {
pub fn len(&self) -> isize {
1
}
pub fn is_empty(&self, x: u32) -> bool {
false
}
}
pub trait WithIsEmpty {
fn len(&self) -> isize;
fn is_empty(&self) -> bool;
}
impl WithIsEmpty for Wither {
fn len(&self) -> isize {
1
}
fn is_empty(&self) -> bool {
false
}
}
struct DerefToDerefToString;
impl Deref for DerefToDerefToString {
type Target = DerefToString;
fn deref(&self) -> &Self::Target {
&DerefToString {}
}
}
struct DerefToString;
impl Deref for DerefToString {
type Target = str;
fn deref(&self) -> &Self::Target {
"Hello, world!"
}
}
fn main() {
let x = [1, 2];
if x.is_empty() {
println!("This should not happen!");
}
if "".is_empty() {}
let s = "Hello, world!";
let s1 = &s;
let s2 = &s1;
let s3 = &s2;
let s4 = &s3;
let s5 = &s4;
let s6 = &s5;
println!("{}", s1.is_empty());
println!("{}", s2.is_empty());
println!("{}", s3.is_empty());
println!("{}", s4.is_empty());
println!("{}", s5.is_empty());
println!("{}", (s6).is_empty());
let d2s = DerefToDerefToString {};
println!("{}", (**d2s).is_empty());
let y = One;
if y.len() == 0 {
// No error; `One` does not have `.is_empty()`.
println!("This should not happen either!");
}
let z: &dyn TraitsToo = &y;
if z.len() > 0 {
// No error; `TraitsToo` has no `.is_empty()` method.
println!("Nor should this!");
}
let has_is_empty = HasIsEmpty;
if has_is_empty.is_empty() {
println!("Or this!");
}
if !has_is_empty.is_empty() {
println!("Or this!");
}
if !has_is_empty.is_empty() {
println!("Or this!");
}
if has_is_empty.is_empty() {
println!("Or this!");
}
if !has_is_empty.is_empty() {
println!("Or this!");
}
if has_is_empty.len() > 1 {
// No error.
println!("This can happen.");
}
if has_is_empty.len() <= 1 {
// No error.
println!("This can happen.");
}
if has_is_empty.is_empty() {
println!("Or this!");
}
if !has_is_empty.is_empty() {
println!("Or this!");
}
if !has_is_empty.is_empty() {
println!("Or this!");
}
if !has_is_empty.is_empty() {
println!("Or this!");
}
if has_is_empty.is_empty() {
println!("Or this!");
}
if 1 < has_is_empty.len() {
// No error.
println!("This can happen.");
}
if 1 >= has_is_empty.len() {
// No error.
println!("This can happen.");
}
assert!(!has_is_empty.is_empty());
let with_is_empty: &dyn WithIsEmpty = &Wither;
if with_is_empty.is_empty() {
println!("Or this!");
}
assert!(!with_is_empty.is_empty());
let has_wrong_is_empty = HasWrongIsEmpty;
if has_wrong_is_empty.len() == 0 {
// No error; `HasWrongIsEmpty` does not have `.is_empty()`.
println!("Or this!");
}
// issue #10529
(!has_is_empty.is_empty()).then(|| println!("This can happen."));
(has_is_empty.is_empty()).then(|| println!("Or this!"));
}
fn test_slice(b: &[u8]) {
if !b.is_empty() {}
}
|
