mirror of
https://github.com/rust-lang/rust-clippy
synced 2024-12-11 22:02:55 +00:00
297 lines
7.6 KiB
Rust
297 lines
7.6 KiB
Rust
#![deny(clippy::useless_conversion)]
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#![allow(clippy::needless_if, clippy::unnecessary_wraps)]
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fn test_generic<T: Copy>(val: T) -> T {
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let _ = val;
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val
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}
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fn test_generic2<T: Copy + Into<i32> + Into<U>, U: From<T>>(val: T) {
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// ok
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let _: i32 = val.into();
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let _: U = val.into();
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let _ = U::from(val);
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}
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fn test_questionmark() -> Result<(), ()> {
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{
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let _: i32 = 0i32;
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Ok(Ok(()))
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}??;
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Ok(())
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}
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fn test_issue_3913() -> Result<(), std::io::Error> {
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use std::fs;
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use std::path::Path;
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let path = Path::new(".");
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for _ in fs::read_dir(path)? {}
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Ok(())
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}
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fn dont_lint_on_type_alias() {
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type A = i32;
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_ = A::from(0i32);
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}
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fn dont_lint_into_iter_on_immutable_local_implementing_iterator_in_expr() {
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let text = "foo\r\nbar\n\nbaz\n";
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let lines = text.lines();
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if Some("ok") == lines.into_iter().next() {}
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}
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fn lint_into_iter_on_mutable_local_implementing_iterator_in_expr() {
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let text = "foo\r\nbar\n\nbaz\n";
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let mut lines = text.lines();
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if Some("ok") == lines.next() {}
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}
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fn lint_into_iter_on_expr_implementing_iterator() {
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let text = "foo\r\nbar\n\nbaz\n";
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let mut lines = text.lines();
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if Some("ok") == lines.next() {}
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}
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fn lint_into_iter_on_expr_implementing_iterator_2() {
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let text = "foo\r\nbar\n\nbaz\n";
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if Some("ok") == text.lines().next() {}
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}
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#[allow(const_item_mutation)]
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fn lint_into_iter_on_const_implementing_iterator() {
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const NUMBERS: std::ops::Range<i32> = 0..10;
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let _ = NUMBERS.next();
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}
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fn lint_into_iter_on_const_implementing_iterator_2() {
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const NUMBERS: std::ops::Range<i32> = 0..10;
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let mut n = NUMBERS;
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n.next();
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}
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#[derive(Clone, Copy)]
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struct CopiableCounter {
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counter: u32,
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}
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impl Iterator for CopiableCounter {
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type Item = u32;
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fn next(&mut self) -> Option<Self::Item> {
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self.counter = self.counter.wrapping_add(1);
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Some(self.counter)
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}
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}
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fn dont_lint_into_iter_on_copy_iter() {
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let mut c = CopiableCounter { counter: 0 };
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assert_eq!(c.into_iter().next(), Some(1));
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assert_eq!(c.into_iter().next(), Some(1));
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assert_eq!(c.next(), Some(1));
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assert_eq!(c.next(), Some(2));
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}
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fn dont_lint_into_iter_on_static_copy_iter() {
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static mut C: CopiableCounter = CopiableCounter { counter: 0 };
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unsafe {
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assert_eq!(C.into_iter().next(), Some(1));
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assert_eq!(C.into_iter().next(), Some(1));
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assert_eq!(C.next(), Some(1));
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assert_eq!(C.next(), Some(2));
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}
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}
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fn main() {
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test_generic(10i32);
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test_generic2::<i32, i32>(10i32);
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test_questionmark().unwrap();
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test_issue_3913().unwrap();
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dont_lint_on_type_alias();
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dont_lint_into_iter_on_immutable_local_implementing_iterator_in_expr();
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lint_into_iter_on_mutable_local_implementing_iterator_in_expr();
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lint_into_iter_on_expr_implementing_iterator();
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lint_into_iter_on_expr_implementing_iterator_2();
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lint_into_iter_on_const_implementing_iterator();
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lint_into_iter_on_const_implementing_iterator_2();
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dont_lint_into_iter_on_copy_iter();
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dont_lint_into_iter_on_static_copy_iter();
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let _: String = "foo".into();
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let _: String = From::from("foo");
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let _ = String::from("foo");
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#[allow(clippy::useless_conversion)]
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{
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let _: String = "foo".into();
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let _ = String::from("foo");
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let _ = "".lines().into_iter();
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}
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let _: String = "foo".to_string();
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let _: String = "foo".to_string();
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let _ = "foo".to_string();
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let _ = format!("A: {:04}", 123);
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let _ = "".lines();
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let _ = vec![1, 2, 3].into_iter();
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let _: String = format!("Hello {}", "world");
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// keep parentheses around `a + b` for suggestion (see #4750)
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let a: i32 = 1;
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let b: i32 = 1;
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let _ = (a + b) * 3;
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// see #7205
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let s: Foo<'a'> = Foo;
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let _: Foo<'b'> = s.into();
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let s2: Foo<'a'> = Foo;
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let _: Foo<'a'> = s2;
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let s3: Foo<'a'> = Foo;
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let _ = s3;
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let s4: Foo<'a'> = Foo;
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let _ = vec![s4, s4, s4].into_iter();
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issue11300::bar();
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}
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#[allow(dead_code)]
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fn issue11065_fp() {
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use std::option::IntoIter;
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fn takes_into_iter(_: impl IntoIterator<Item = i32>) {}
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macro_rules! x {
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($e:expr) => {
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takes_into_iter($e);
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let _: IntoIter<i32> = $e; // removing `.into_iter()` leads to a type error here
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};
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}
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x!(Some(5).into_iter());
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}
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#[allow(dead_code)]
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fn explicit_into_iter_fn_arg() {
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fn a<T>(_: T) {}
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fn b<T: IntoIterator<Item = i32>>(_: T) {}
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fn c(_: impl IntoIterator<Item = i32>) {}
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fn d<T>(_: T)
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where
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T: IntoIterator<Item = i32>,
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{
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}
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fn f(_: std::vec::IntoIter<i32>) {}
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a(vec![1, 2].into_iter());
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b(vec![1, 2]);
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c(vec![1, 2]);
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d(vec![1, 2]);
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b([&1, &2, &3].into_iter().cloned());
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b(vec![1, 2]);
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b(vec![1, 2]);
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macro_rules! macro_generated {
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() => {
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vec![1, 2].into_iter()
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};
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}
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b(macro_generated!());
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}
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mod issue11300 {
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pub fn foo<I>(i: I)
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where
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I: IntoIterator<Item = i32> + ExactSizeIterator,
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{
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assert_eq!(i.len(), 3);
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}
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trait Helper<T: ?Sized> {}
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impl Helper<i32> for [i32; 3] {}
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impl Helper<i32> for std::array::IntoIter<i32, 3> {}
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impl Helper<()> for std::array::IntoIter<i32, 3> {}
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fn foo2<X: ?Sized, I>(_: I)
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where
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I: IntoIterator<Item = i32> + Helper<X>,
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{
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}
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trait Helper2<T> {}
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impl Helper2<std::array::IntoIter<i32, 3>> for i32 {}
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impl Helper2<[i32; 3]> for i32 {}
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fn foo3<I>(_: I)
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where
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I: IntoIterator<Item = i32>,
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i32: Helper2<I>,
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{
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}
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pub fn bar() {
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// This should not trigger the lint:
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// `[i32, 3]` does not satisfy the `ExactSizeIterator` bound, so the into_iter call cannot be
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// removed and is not useless.
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foo([1, 2, 3].into_iter());
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// This should trigger the lint, receiver type [i32; 3] also implements `Helper`
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foo2::<i32, _>([1, 2, 3]);
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// This again should *not* lint, since X = () and I = std::array::IntoIter<i32, 3>,
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// and `[i32; 3]: Helper<()>` is not true (only `std::array::IntoIter<i32, 3>: Helper<()>` is).
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foo2::<(), _>([1, 2, 3].into_iter());
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// This should lint. Removing the `.into_iter()` means that `I` gets substituted with `[i32; 3]`,
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// and `i32: Helper2<[i32, 3]>` is true, so this call is indeed unnecessary.
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foo3([1, 2, 3]);
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}
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fn ice() {
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struct S1;
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impl S1 {
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pub fn foo<I: IntoIterator>(&self, _: I) {}
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}
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S1.foo([1, 2]);
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// ICE that occurred in itertools
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trait Itertools {
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fn interleave_shortest<J>(self, other: J)
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where
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J: IntoIterator,
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Self: Sized;
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}
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impl<I: Iterator> Itertools for I {
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fn interleave_shortest<J>(self, other: J)
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where
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J: IntoIterator,
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Self: Sized,
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{
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}
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}
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let v0: Vec<i32> = vec![0, 2, 4];
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let v1: Vec<i32> = vec![1, 3, 5, 7];
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v0.into_iter().interleave_shortest(v1);
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trait TraitWithLifetime<'a> {}
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impl<'a> TraitWithLifetime<'a> for std::array::IntoIter<&'a i32, 2> {}
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struct Helper;
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impl<'a> Helper {
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fn with_lt<I>(&self, _: I)
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where
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I: IntoIterator + TraitWithLifetime<'a>,
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{
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}
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}
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Helper.with_lt([&1, &2].into_iter());
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}
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}
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#[derive(Copy, Clone)]
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struct Foo<const C: char>;
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impl From<Foo<'a'>> for Foo<'b'> {
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fn from(_s: Foo<'a'>) -> Self {
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Foo
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}
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}
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