2022-12-01 11:29:38 -06:00
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#![allow(
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unused,
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2024-01-26 11:48:18 -06:00
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non_local_definitions,
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2022-10-23 08:18:45 -05:00
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clippy::uninlined_format_args,
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clippy::unnecessary_mut_passed,
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2023-07-02 07:35:19 -05:00
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clippy::unnecessary_to_owned,
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2024-08-18 06:31:47 -05:00
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clippy::unnecessary_literal_unwrap,
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clippy::needless_lifetimes
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2022-10-23 08:18:45 -05:00
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)]
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2022-12-01 11:29:38 -06:00
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#![warn(clippy::needless_borrow)]
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2016-04-26 08:49:53 -05:00
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fn main() {
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let a = 5;
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2021-12-06 05:33:31 -06:00
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let ref_a = &a;
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2021-09-28 12:03:12 -05:00
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let _ = x(&a); // no warning
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let _ = x(&&a); // warn
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let mut b = 5;
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mut_ref(&mut b); // no warning
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mut_ref(&mut &mut b); // warn
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2016-04-26 08:49:53 -05:00
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let s = &String::from("hi");
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let s_ident = f(&s); // should not error, because `&String` implements Copy, but `String` does not
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let g_val = g(&Vec::new()); // should not error, because `&Vec<T>` derefs to `&[T]`
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let vec = Vec::new();
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let vec_val = g(&vec); // should not error, because `&Vec<T>` derefs to `&[T]`
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2016-05-27 05:12:38 -05:00
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h(&"foo"); // should not error, because the `&&str` is required, due to `&Trait`
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2017-05-05 07:26:14 -05:00
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let garbl = match 42 {
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44 => &a,
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45 => {
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println!("foo");
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2021-12-06 05:33:31 -06:00
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&&a
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2017-05-05 07:26:14 -05:00
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},
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46 => &&a,
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2021-12-06 05:33:31 -06:00
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47 => {
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println!("foo");
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loop {
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println!("{}", a);
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if a == 25 {
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break &ref_a;
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}
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}
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},
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2017-05-05 07:26:14 -05:00
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_ => panic!(),
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};
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2021-12-06 05:33:31 -06:00
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let _ = x(&&&a);
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let _ = x(&mut &&a);
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let _ = x(&&&mut b);
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let _ = x(&&ref_a);
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{
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let b = &mut b;
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x(&b);
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}
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2022-01-27 08:12:45 -06:00
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// Issue #8191
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let mut x = 5;
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let mut x = &mut x;
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mut_ref(&mut x);
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mut_ref(&mut &mut x);
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let y: &mut i32 = &mut x;
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let y: &mut i32 = &mut &mut x;
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let y = match 0 {
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// Don't lint. Removing the borrow would move 'x'
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0 => &mut x,
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_ => &mut *x,
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};
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2022-06-30 03:50:09 -05:00
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let y: &mut i32 = match 0 {
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// Lint here. The type given above triggers auto-borrow.
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0 => &mut x,
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_ => &mut *x,
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};
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fn ref_mut_i32(_: &mut i32) {}
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ref_mut_i32(match 0 {
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// Lint here. The type given above triggers auto-borrow.
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0 => &mut x,
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_ => &mut *x,
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});
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// use 'x' after to make sure it's still usable in the fixed code.
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2022-01-27 08:12:45 -06:00
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*x = 5;
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let s = String::new();
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2022-02-16 22:14:39 -06:00
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// let _ = (&s).len();
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// let _ = (&s).capacity();
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// let _ = (&&s).capacity();
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2022-01-27 08:12:45 -06:00
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let x = (1, 2);
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let _ = (&x).0;
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let x = &x as *const (i32, i32);
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let _ = unsafe { (&*x).0 };
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2022-06-30 03:50:09 -05:00
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// Issue #8367
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trait Foo {
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fn foo(self);
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}
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impl Foo for &'_ () {
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fn foo(self) {}
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}
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(&()).foo(); // Don't lint. `()` doesn't implement `Foo`
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(&&()).foo();
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impl Foo for i32 {
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fn foo(self) {}
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}
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impl Foo for &'_ i32 {
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fn foo(self) {}
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}
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(&5).foo(); // Don't lint. `5` will call `<i32 as Foo>::foo`
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(&&5).foo();
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trait FooRef {
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fn foo_ref(&self);
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}
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impl FooRef for () {
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fn foo_ref(&self) {}
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}
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impl FooRef for &'_ () {
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fn foo_ref(&self) {}
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}
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(&&()).foo_ref(); // Don't lint. `&()` will call `<() as FooRef>::foo_ref`
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2022-07-18 02:39:37 -05:00
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struct S;
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impl From<S> for u32 {
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fn from(s: S) -> Self {
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(&s).into()
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}
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}
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impl From<&S> for u32 {
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fn from(s: &S) -> Self {
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0
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}
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}
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2024-02-08 13:24:42 -06:00
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// issue #11786
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let x: (&str,) = (&"",);
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2016-04-26 08:49:53 -05:00
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}
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2021-09-28 12:03:12 -05:00
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#[allow(clippy::needless_borrowed_reference)]
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fn x(y: &i32) -> i32 {
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*y
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}
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fn mut_ref(y: &mut i32) {
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*y = 5;
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}
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2018-12-09 16:26:16 -06:00
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fn f<T: Copy>(y: &T) -> T {
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2016-04-26 08:49:53 -05:00
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*y
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}
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fn g(y: &[u8]) -> u8 {
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y[0]
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}
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2016-05-27 05:12:38 -05:00
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trait Trait {}
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impl<'a> Trait for &'a str {}
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2019-05-30 01:23:47 -05:00
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fn h(_: &dyn Trait) {}
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2022-06-16 10:39:06 -05:00
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fn check_expect_suppression() {
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let a = 5;
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#[expect(clippy::needless_borrow)]
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let _ = x(&&a);
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}
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2022-07-28 12:08:22 -05:00
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mod issue9160 {
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pub struct S<F> {
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f: F,
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}
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impl<T, F> S<F>
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where
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F: Fn() -> T,
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{
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fn calls_field(&self) -> T {
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(&self.f)()
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}
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}
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impl<T, F> S<F>
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where
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F: FnMut() -> T,
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{
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fn calls_mut_field(&mut self) -> T {
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(&mut self.f)()
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}
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}
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}
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2022-08-31 08:24:45 -05:00
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2022-10-06 02:44:38 -05:00
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fn issue9383() {
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// Should not lint because unions need explicit deref when accessing field
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use std::mem::ManuallyDrop;
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2023-11-16 12:13:24 -06:00
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#[derive(Clone, Copy)]
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struct Wrap<T>(T);
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impl<T> core::ops::Deref for Wrap<T> {
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type Target = T;
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fn deref(&self) -> &T {
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&self.0
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}
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}
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impl<T> core::ops::DerefMut for Wrap<T> {
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fn deref_mut(&mut self) -> &mut T {
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&mut self.0
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}
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2022-10-06 02:44:38 -05:00
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}
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2023-11-16 12:13:24 -06:00
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union U<T: Copy> {
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u: T,
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2022-10-06 02:44:38 -05:00
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}
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2023-11-16 12:13:24 -06:00
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#[derive(Clone, Copy)]
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struct Foo {
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x: u32,
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}
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2022-10-06 02:44:38 -05:00
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unsafe {
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2023-11-16 12:13:24 -06:00
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let mut x = U {
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u: ManuallyDrop::new(Foo { x: 0 }),
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};
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let _ = &mut (&mut x.u).x;
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let _ = &mut (&mut { x.u }).x;
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let _ = &mut ({ &mut x.u }).x;
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let mut x = U {
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u: Wrap(ManuallyDrop::new(Foo { x: 0 })),
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};
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let _ = &mut (&mut x.u).x;
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let _ = &mut (&mut { x.u }).x;
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let _ = &mut ({ &mut x.u }).x;
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let mut x = U { u: Wrap(Foo { x: 0 }) };
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let _ = &mut (&mut x.u).x;
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let _ = &mut (&mut { x.u }).x;
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let _ = &mut ({ &mut x.u }).x;
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2022-10-06 02:44:38 -05:00
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}
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}
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2022-10-23 08:18:45 -05:00
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2023-09-12 11:13:53 -05:00
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mod issue_10253 {
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struct S;
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trait X {
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fn f<T>(&self);
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}
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impl X for &S {
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fn f<T>(&self) {}
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}
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fn f() {
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(&S).f::<()>();
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}
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}
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2024-04-18 10:48:52 -05:00
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fn issue_12268() {
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let option = Some((&1,));
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let x = (&1,);
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option.unwrap_or((&x.0,));
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//~^ ERROR: this expression creates a reference which is immediately dereferenced by the
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// compiler
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}
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