// run-rustfix #![feature(custom_inner_attributes, lint_reasons)] #[warn(clippy::all, clippy::needless_borrow)] #[allow(unused_variables, clippy::unnecessary_mut_passed)] fn main() { let a = 5; let ref_a = &a; let _ = x(&a); // no warning let _ = x(&a); // warn let mut b = 5; mut_ref(&mut b); // no warning mut_ref(&mut b); // warn let s = &String::from("hi"); let s_ident = f(&s); // should not error, because `&String` implements Copy, but `String` does not let g_val = g(&Vec::new()); // should not error, because `&Vec` derefs to `&[T]` let vec = Vec::new(); let vec_val = g(&vec); // should not error, because `&Vec` derefs to `&[T]` h(&"foo"); // should not error, because the `&&str` is required, due to `&Trait` let garbl = match 42 { 44 => &a, 45 => { println!("foo"); &a }, 46 => &a, 47 => { println!("foo"); loop { println!("{}", a); if a == 25 { break ref_a; } } }, _ => panic!(), }; let _ = x(&a); let _ = x(&a); let _ = x(&mut b); let _ = x(ref_a); { let b = &mut b; x(b); } // Issue #8191 let mut x = 5; let mut x = &mut x; mut_ref(x); mut_ref(x); let y: &mut i32 = x; let y: &mut i32 = x; let y = match 0 { // Don't lint. Removing the borrow would move 'x' 0 => &mut x, _ => &mut *x, }; let y: &mut i32 = match 0 { // Lint here. The type given above triggers auto-borrow. 0 => x, _ => &mut *x, }; fn ref_mut_i32(_: &mut i32) {} ref_mut_i32(match 0 { // Lint here. The type given above triggers auto-borrow. 0 => x, _ => &mut *x, }); // use 'x' after to make sure it's still usable in the fixed code. *x = 5; let s = String::new(); // let _ = (&s).len(); // let _ = (&s).capacity(); // let _ = (&&s).capacity(); let x = (1, 2); let _ = x.0; let x = &x as *const (i32, i32); let _ = unsafe { (*x).0 }; // Issue #8367 trait Foo { fn foo(self); } impl Foo for &'_ () { fn foo(self) {} } (&()).foo(); // Don't lint. `()` doesn't implement `Foo` (&()).foo(); impl Foo for i32 { fn foo(self) {} } impl Foo for &'_ i32 { fn foo(self) {} } (&5).foo(); // Don't lint. `5` will call `::foo` (&5).foo(); trait FooRef { fn foo_ref(&self); } impl FooRef for () { fn foo_ref(&self) {} } impl FooRef for &'_ () { fn foo_ref(&self) {} } (&&()).foo_ref(); // Don't lint. `&()` will call `<() as FooRef>::foo_ref` struct S; impl From for u32 { fn from(s: S) -> Self { (&s).into() } } impl From<&S> for u32 { fn from(s: &S) -> Self { 0 } } let _ = std::process::Command::new("ls").args(["-a", "-l"]).status().unwrap(); let _ = std::path::Path::new(".").join("."); deref_target_is_x(X); multiple_constraints([[""]]); multiple_constraints_normalizes_to_same(X, X); let _ = Some("").unwrap_or(""); only_sized(&""); // Don't lint. `Sized` is only bound let _ = std::any::Any::type_id(&""); // Don't lint. `Any` is only bound let _ = Box::new(&""); // Don't lint. Type parameter appears in return type ref_as_ref_path(&""); // Don't lint. Argument type is not a type parameter refs_only(&()); // Don't lint. `&T` implements trait, but `T` doesn't multiple_constraints_normalizes_to_different(&[[""]], &[""]); // Don't lint. Projected type appears in arguments } #[allow(clippy::needless_borrowed_reference)] fn x(y: &i32) -> i32 { *y } fn mut_ref(y: &mut i32) { *y = 5; } fn f(y: &T) -> T { *y } fn g(y: &[u8]) -> u8 { y[0] } trait Trait {} impl<'a> Trait for &'a str {} fn h(_: &dyn Trait) {} #[allow(dead_code)] fn check_expect_suppression() { let a = 5; #[expect(clippy::needless_borrow)] let _ = x(&&a); } #[allow(dead_code)] mod issue9160 { pub struct S { f: F, } impl S where F: Fn() -> T, { fn calls_field(&self) -> T { (self.f)() } } impl S where F: FnMut() -> T, { fn calls_mut_field(&mut self) -> T { (self.f)() } } } #[derive(Clone, Copy)] struct X; impl std::ops::Deref for X { type Target = X; fn deref(&self) -> &Self::Target { self } } fn deref_target_is_x(_: T) where T: std::ops::Deref, { } fn multiple_constraints(_: T) where T: IntoIterator + IntoIterator, U: IntoIterator, V: AsRef, X: IntoIterator, Y: AsRef, { } fn multiple_constraints_normalizes_to_same(_: T, _: V) where T: std::ops::Deref, U: std::ops::Deref, { } fn only_sized(_: T) {} fn ref_as_ref_path(_: &'static T) where &'static T: AsRef, { } trait RefsOnly { type Referent; } impl RefsOnly for &T { type Referent = T; } fn refs_only(_: T) where T: RefsOnly, { } fn multiple_constraints_normalizes_to_different(_: T, _: U) where T: IntoIterator, U: IntoIterator, V: AsRef, { } // https://github.com/rust-lang/rust-clippy/pull/9136#pullrequestreview-1037379321 #[allow(dead_code)] mod copyable_iterator { #[derive(Clone, Copy)] struct Iter; impl Iterator for Iter { type Item = (); fn next(&mut self) -> Option { None } } fn takes_iter(_: impl Iterator) {} fn dont_warn(mut x: Iter) { takes_iter(&mut x); } fn warn(mut x: &mut Iter) { takes_iter(&mut x) } } mod under_msrv { #![allow(dead_code)] #![clippy::msrv = "1.52.0"] fn foo() { let _ = std::process::Command::new("ls").args(&["-a", "-l"]).status().unwrap(); } } mod meets_msrv { #![allow(dead_code)] #![clippy::msrv = "1.53.0"] fn foo() { let _ = std::process::Command::new("ls").args(["-a", "-l"]).status().unwrap(); } } #[allow(unused)] fn issue9383() { // Should not lint because unions need explicit deref when accessing field use std::mem::ManuallyDrop; union Coral { crab: ManuallyDrop>, } union Ocean { coral: ManuallyDrop, } let mut ocean = Ocean { coral: ManuallyDrop::new(Coral { crab: ManuallyDrop::new(vec![1, 2, 3]), }), }; unsafe { ManuallyDrop::drop(&mut (&mut ocean.coral).crab); (*ocean.coral).crab = ManuallyDrop::new(vec![4, 5, 6]); ManuallyDrop::drop(&mut (*ocean.coral).crab); ManuallyDrop::drop(&mut ocean.coral); } }