mirror of
https://github.com/rust-lang/rust.git
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197 lines
4.1 KiB
Rust
197 lines
4.1 KiB
Rust
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#![warn(while_let_loop, empty_loop, while_let_on_iterator)]
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#![allow(dead_code, never_loop, unused, cyclomatic_complexity)]
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fn main() {
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let y = Some(true);
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loop {
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if let Some(_x) = y {
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let _v = 1;
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} else {
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break
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}
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}
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loop { // no error, break is not in else clause
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if let Some(_x) = y {
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let _v = 1;
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}
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break;
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}
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loop {
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match y {
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Some(_x) => true,
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None => break
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};
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}
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loop {
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let x = match y {
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Some(x) => x,
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None => break
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};
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let _x = x;
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let _str = "foo";
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}
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loop {
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let x = match y {
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Some(x) => x,
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None => break,
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};
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{ let _a = "bar"; };
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{ let _b = "foobar"; }
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}
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loop { // no error, else branch does something other than break
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match y {
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Some(_x) => true,
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_ => {
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let _z = 1;
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break;
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}
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};
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}
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while let Some(x) = y { // no error, obviously
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println!("{}", x);
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}
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// #675, this used to have a wrong suggestion
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loop {
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let (e, l) = match "".split_whitespace().next() {
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Some(word) => (word.is_empty(), word.len()),
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None => break
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};
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let _ = (e, l);
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}
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let mut iter = 1..20;
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while let Option::Some(x) = iter.next() {
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println!("{}", x);
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}
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let mut iter = 1..20;
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while let Some(x) = iter.next() {
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println!("{}", x);
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}
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let mut iter = 1..20;
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while let Some(_) = iter.next() {}
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let mut iter = 1..20;
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while let None = iter.next() {} // this is fine (if nonsensical)
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let mut iter = 1..20;
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if let Some(x) = iter.next() { // also fine
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println!("{}", x)
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}
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// the following shouldn't warn because it can't be written with a for loop
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let mut iter = 1u32..20;
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while let Some(x) = iter.next() {
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println!("next: {:?}", iter.next())
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}
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// neither can this
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let mut iter = 1u32..20;
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while let Some(x) = iter.next() {
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println!("next: {:?}", iter.next());
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}
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// or this
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let mut iter = 1u32..20;
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while let Some(x) = iter.next() {break;}
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println!("Remaining iter {:?}", iter);
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// or this
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let mut iter = 1u32..20;
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while let Some(x) = iter.next() {
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iter = 1..20;
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}
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}
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// regression test (#360)
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// this should not panic
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// it's okay if further iterations of the lint
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// cause this function to trigger it
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fn no_panic<T>(slice: &[T]) {
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let mut iter = slice.iter();
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loop {
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let _ = match iter.next() {
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Some(ele) => ele,
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None => break
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};
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loop {}
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}
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}
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fn issue1017() {
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let r: Result<u32, u32> = Ok(42);
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let mut len = 1337;
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loop {
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match r {
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Err(_) => len = 0,
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Ok(length) => {
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len = length;
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break
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}
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}
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}
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}
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// Issue #1188
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fn refutable() {
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let a = [42, 1337];
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let mut b = a.iter();
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// consume all the 42s
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while let Some(&42) = b.next() {
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}
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let a = [(1, 2, 3)];
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let mut b = a.iter();
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while let Some(&(1, 2, 3)) = b.next() {
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}
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let a = [Some(42)];
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let mut b = a.iter();
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while let Some(&None) = b.next() {
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}
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/* This gives “refutable pattern in `for` loop binding: `&_` not covered”
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for &42 in b {}
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for &(1, 2, 3) in b {}
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for &Option::None in b.next() {}
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// */
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let mut y = a.iter();
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loop { // x is reused, so don't lint here
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while let Some(v) = y.next() {
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}
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}
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let mut y = a.iter();
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for _ in 0..2 {
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while let Some(v) = y.next() { // y is reused, don't lint
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}
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}
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loop {
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let mut y = a.iter();
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while let Some(v) = y.next() { // use a for loop here
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}
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}
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// should not trigger while_let_loop lint because break passes an expression
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let a = Some(10);
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let b = loop {
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if let Some(c) = a {
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break Some(c);
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} else {
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break None;
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}
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};
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}
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