-#![feature(iterator_for_each)]
-
use std::iter::repeat;
-#[allow(trivially_copy_pass_by_ref)]
-fn square_is_lower_64(x: &u32) -> bool { x * x < 64 }
+fn square_is_lower_64(x: &u32) -> bool {
+ x * x < 64
+}
-#[allow(maybe_infinite_iter)]
-#[deny(infinite_iter)]
+#[allow(clippy::maybe_infinite_iter)]
+#[deny(clippy::infinite_iter)]
fn infinite_iters() {
repeat(0_u8).collect::<Vec<_>>(); // infinite iter
(0..8_u32).take_while(square_is_lower_64).cycle().count(); // infinite iter
(0..8_u64).chain(0..).max(); // infinite iter
- (0_usize..).chain([0usize, 1, 2].iter().cloned()).skip_while(|x| *x != 42).min(); // infinite iter
- (0..8_u32).rev().cycle().map(|x| x + 1_u32).for_each(|x| println!("{}", x)); // infinite iter
+ (0_usize..)
+ .chain([0usize, 1, 2].iter().cloned())
+ .skip_while(|x| *x != 42)
+ .min(); // infinite iter
+ (0..8_u32)
+ .rev()
+ .cycle()
+ .map(|x| x + 1_u32)
+ .for_each(|x| println!("{}", x)); // infinite iter
(0..3_u32).flat_map(|x| x..).sum::<u32>(); // infinite iter
- (0_usize..).flat_map(|x| 0..x).product::<usize>(); // infinite iter
+ (0_usize..).flat_map(|x| 0..x).product::<usize>(); // infinite iter
(0_u64..).filter(|x| x % 2 == 0).last(); // infinite iter
(0..42_u64).by_ref().last(); // not an infinite, because ranges are double-ended
(0..).next(); // iterator is not exhausted
}
-#[deny(maybe_infinite_iter)]
+#[deny(clippy::maybe_infinite_iter)]
fn potential_infinite_iters() {
(0..).zip((0..).take_while(square_is_lower_64)).count(); // maybe infinite iter
repeat(42).take_while(|x| *x == 42).chain(0..42).max(); // maybe infinite iter
- (1..).scan(0, |state, x| { *state += x; Some(*state) }).min(); // maybe infinite iter
+ (1..)
+ .scan(0, |state, x| {
+ *state += x;
+ Some(*state)
+ })
+ .min(); // maybe infinite iter
(0..).find(|x| *x == 24); // maybe infinite iter
(0..).position(|x| x == 24); // maybe infinite iter
(0..).any(|x| x == 24); // maybe infinite iter
infinite_iters();
potential_infinite_iters();
}
+
+mod finite_collect {
+ use std::collections::HashSet;
+ use std::iter::FromIterator;
+
+ struct C;
+ impl FromIterator<i32> for C {
+ fn from_iter<I: IntoIterator<Item = i32>>(iter: I) -> Self {
+ C
+ }
+ }
+
+ fn check_collect() {
+ let _: HashSet<i32> = (0..).collect(); // Infinite iter
+
+ // Some data structures don't collect infinitely, such as `ArrayVec`
+ let _: C = (0..).collect();
+ }
+}