#![allow( unused, clippy::many_single_char_names, clippy::needless_lifetimes, clippy::redundant_clone, clippy::needless_pass_by_ref_mut )] #![warn(clippy::ptr_arg)] //@no-rustfix use std::borrow::Cow; use std::path::{Path, PathBuf}; fn do_vec(x: &Vec) { //~^ ERROR: writing `&Vec` instead of `&[_]` involves a new object where a slice will do //~| NOTE: `-D clippy::ptr-arg` implied by `-D warnings` //Nothing here } fn do_vec_mut(x: &mut Vec) { //~^ ERROR: writing `&mut Vec` instead of `&mut [_]` involves a new object where a slice w //Nothing here } fn do_vec_mut2(x: &mut Vec) { //~^ ERROR: writing `&mut Vec` instead of `&mut [_]` involves a new object where a slice w x.len(); x.is_empty(); } fn do_str(x: &String) { //~^ ERROR: writing `&String` instead of `&str` involves a new object where a slice will d //Nothing here either } fn do_str_mut(x: &mut String) { //~^ ERROR: writing `&mut String` instead of `&mut str` involves a new object where a slic //Nothing here either } fn do_path(x: &PathBuf) { //~^ ERROR: writing `&PathBuf` instead of `&Path` involves a new object where a slice will //Nothing here either } fn do_path_mut(x: &mut PathBuf) { //~^ ERROR: writing `&mut PathBuf` instead of `&mut Path` involves a new object where a sl //Nothing here either } fn main() {} trait Foo { type Item; fn do_vec(x: &Vec); //~^ ERROR: writing `&Vec` instead of `&[_]` involves a new object where a slice will fn do_item(x: &Self::Item); } struct Bar; // no error, in trait impl (#425) impl Foo for Bar { type Item = Vec; fn do_vec(x: &Vec) {} fn do_item(x: &Vec) {} } fn cloned(x: &Vec) -> Vec { //~^ ERROR: writing `&Vec` instead of `&[_]` involves a new object where a slice will do let e = x.clone(); let f = e.clone(); // OK let g = x; let h = g.clone(); let i = (e).clone(); x.clone() } fn str_cloned(x: &String) -> String { //~^ ERROR: writing `&String` instead of `&str` involves a new object where a slice will d let a = x.clone(); let b = x.clone(); let c = b.clone(); let d = a.clone().clone().clone(); x.clone() } fn path_cloned(x: &PathBuf) -> PathBuf { //~^ ERROR: writing `&PathBuf` instead of `&Path` involves a new object where a slice will let a = x.clone(); let b = x.clone(); let c = b.clone(); let d = a.clone().clone().clone(); x.clone() } fn false_positive_capacity(x: &Vec, y: &String) { //~^ ERROR: writing `&String` instead of `&str` involves a new object where a slice will d let a = x.capacity(); let b = y.clone(); let c = y.as_str(); } fn false_positive_capacity_too(x: &String) -> String { if x.capacity() > 1024 { panic!("Too large!"); } x.clone() } #[allow(dead_code)] fn test_cow_with_ref(c: &Cow<[i32]>) {} //~^ ERROR: using a reference to `Cow` is not recommended fn test_cow(c: Cow<[i32]>) { let _c = c; } trait Foo2 { fn do_string(&self); } // no error for &self references where self is of type String (#2293) impl Foo2 for String { fn do_string(&self) {} } // Check that the allow attribute on parameters is honored mod issue_5644 { use std::borrow::Cow; use std::path::PathBuf; fn allowed( #[allow(clippy::ptr_arg)] _v: &Vec, #[allow(clippy::ptr_arg)] _s: &String, #[allow(clippy::ptr_arg)] _p: &PathBuf, #[allow(clippy::ptr_arg)] _c: &Cow<[i32]>, #[expect(clippy::ptr_arg)] _expect: &Cow<[i32]>, ) { } fn some_allowed(#[allow(clippy::ptr_arg)] _v: &Vec, _s: &String) {} //~^ ERROR: writing `&String` instead of `&str` involves a new object where a slice wi struct S; impl S { fn allowed( #[allow(clippy::ptr_arg)] _v: &Vec, #[allow(clippy::ptr_arg)] _s: &String, #[allow(clippy::ptr_arg)] _p: &PathBuf, #[allow(clippy::ptr_arg)] _c: &Cow<[i32]>, #[expect(clippy::ptr_arg)] _expect: &Cow<[i32]>, ) { } } trait T { fn allowed( #[allow(clippy::ptr_arg)] _v: &Vec, #[allow(clippy::ptr_arg)] _s: &String, #[allow(clippy::ptr_arg)] _p: &PathBuf, #[allow(clippy::ptr_arg)] _c: &Cow<[i32]>, #[expect(clippy::ptr_arg)] _expect: &Cow<[i32]>, ) { } } } mod issue6509 { use std::path::PathBuf; fn foo_vec(vec: &Vec) { //~^ ERROR: writing `&Vec` instead of `&[_]` involves a new object where a slice will let _ = vec.clone().pop(); let _ = vec.clone().clone(); } fn foo_path(path: &PathBuf) { //~^ ERROR: writing `&PathBuf` instead of `&Path` involves a new object where a slice let _ = path.clone().pop(); let _ = path.clone().clone(); } fn foo_str(str: &PathBuf) { //~^ ERROR: writing `&PathBuf` instead of `&Path` involves a new object where a slice let _ = str.clone().pop(); let _ = str.clone().clone(); } } fn mut_vec_slice_methods(v: &mut Vec) { //~^ ERROR: writing `&mut Vec` instead of `&mut [_]` involves a new object where a slice w v.copy_within(1..5, 10); } fn mut_vec_vec_methods(v: &mut Vec) { v.clear(); } fn vec_contains(v: &Vec) -> bool { [vec![], vec![0]].as_slice().contains(v) } fn fn_requires_vec(v: &Vec) -> bool { vec_contains(v) } fn impl_fn_requires_vec(v: &Vec, f: impl Fn(&Vec)) { f(v); } fn dyn_fn_requires_vec(v: &Vec, f: &dyn Fn(&Vec)) { f(v); } // No error for types behind an alias (#7699) type A = Vec; fn aliased(a: &A) {} // Issue #8366 pub trait Trait { fn f(v: &mut Vec); fn f2(v: &mut Vec) {} } // Issue #8463 fn two_vecs(a: &mut Vec, b: &mut Vec) { a.push(0); a.push(0); a.push(0); b.push(1); } // Issue #8495 fn cow_conditional_to_mut(a: &mut Cow) { if a.is_empty() { a.to_mut().push_str("foo"); } } // Issue #9542 fn dyn_trait_ok(a: &mut Vec, b: &mut String, c: &mut PathBuf) { trait T {} impl T for Vec {} impl T for String {} impl T for PathBuf {} fn takes_dyn(_: &mut dyn T) {} takes_dyn(a); takes_dyn(b); takes_dyn(c); } fn dyn_trait(a: &mut Vec, b: &mut String, c: &mut PathBuf) { //~^ ERROR: writing `&mut Vec` instead of `&mut [_]` involves a new object where a slice w //~| ERROR: writing `&mut String` instead of `&mut str` involves a new object where a slic //~| ERROR: writing `&mut PathBuf` instead of `&mut Path` involves a new object where a sl trait T {} impl T for Vec {} impl T for [U] {} impl T for String {} impl T for str {} impl T for PathBuf {} impl T for Path {} fn takes_dyn(_: &mut dyn T) {} takes_dyn(a); takes_dyn(b); takes_dyn(c); } mod issue_9218 { use std::borrow::Cow; fn cow_non_elided_lifetime<'a>(input: &Cow<'a, str>) -> &'a str { todo!() } // This one has an anonymous lifetime so it's not okay fn cow_elided_lifetime<'a>(input: &'a Cow) -> &'a str { //~^ ERROR: using a reference to `Cow` is not recommended todo!() } // These two's return types don't use 'a so it's not okay fn cow_bad_ret_ty_1<'a>(input: &'a Cow<'a, str>) -> &'static str { //~^ ERROR: using a reference to `Cow` is not recommended todo!() } fn cow_bad_ret_ty_2<'a, 'b>(input: &'a Cow<'a, str>) -> &'b str { //~^ ERROR: using a reference to `Cow` is not recommended todo!() } // Inferred to be `&'a str`, afaik. fn cow_good_ret_ty<'a>(input: &'a Cow<'a, str>) -> &str { todo!() } } mod issue_11181 { extern "C" fn allowed(_v: &Vec) {} struct S; impl S { extern "C" fn allowed(_v: &Vec) {} } trait T { extern "C" fn allowed(_v: &Vec) {} } } mod issue_13308 { use std::ops::Deref; fn repro(source: &str, destination: &mut String) { source.clone_into(destination); } fn repro2(source: &str, destination: &mut String) { ToOwned::clone_into(source, destination); } fn h1(_: &::Target) {} fn h2(_: T, _: &T::Target) {} // Other cases that are still ok to lint and ideally shouldn't regress fn good(v1: &String, v2: &String) { //~^ ERROR: writing `&String` instead of `&str` //~^^ ERROR: writing `&String` instead of `&str` h1(v1); h2(String::new(), v2); } }