//@aux-build:proc_macro_derive.rs:proc-macro #![allow( unused, dead_code, clippy::needless_lifetimes, clippy::needless_pass_by_value, clippy::needless_arbitrary_self_type )] #![warn(clippy::extra_unused_lifetimes)] #[macro_use] extern crate proc_macro_derive; fn empty() {} fn used_lt<'a>(x: &'a u8) {} fn unused_lt<'a>(x: u8) {} fn unused_lt_transitive<'a, 'b: 'a>(x: &'b u8) { // 'a is useless here since it's not directly bound } fn lt_return<'a, 'b: 'a>(x: &'b u8) -> &'a u8 { panic!() } fn lt_return_only<'a>() -> &'a u8 { panic!() } fn unused_lt_blergh<'a>(x: Option>) {} trait Foo<'a> { fn x(&self, a: &'a u8); } impl<'a> Foo<'a> for u8 { fn x(&self, a: &'a u8) {} } struct Bar; impl Bar { fn x<'a>(&self) {} } // test for #489 (used lifetimes in bounds) pub fn parse<'a, I: Iterator>(_it: &mut I) { unimplemented!() } pub fn parse2<'a, I>(_it: &mut I) where I: Iterator, { unimplemented!() } struct X { x: u32, } impl X { fn self_ref_with_lifetime<'a>(&'a self) {} fn explicit_self_with_lifetime<'a>(self: &'a Self) {} } // Methods implementing traits must have matching lifetimes mod issue4291 { trait BadTrait { fn unused_lt<'a>(x: u8) {} } impl BadTrait for () { fn unused_lt<'a>(_x: u8) {} } } mod issue6437 { pub struct Scalar; impl<'a> std::ops::AddAssign<&Scalar> for &mut Scalar { fn add_assign(&mut self, _rhs: &Scalar) { unimplemented!(); } } impl<'b> Scalar { pub fn something<'c>() -> Self { Self } } } // https://github.com/rust-lang/rust-clippy/pull/8737#pullrequestreview-951268213 mod first_case { use serde::de::Visitor; pub trait Expected { fn fmt(&self, formatter: &mut std::fmt::Formatter); } impl<'de, T> Expected for T where T: Visitor<'de>, { fn fmt(&self, formatter: &mut std::fmt::Formatter) {} } } // https://github.com/rust-lang/rust-clippy/pull/8737#pullrequestreview-951268213 mod second_case { pub trait Source { fn hey(); } impl<'a, T: Source + ?Sized + 'a> Source for Box { fn hey() {} } } // Should not lint #[derive(ExtraLifetimeDerive)] struct Human<'a> { pub bones: i32, pub name: &'a str, } fn main() {}