#![warn(use_self)] #![allow(dead_code)] #![allow(should_implement_trait)] #![allow(boxed_local)] fn main() {} mod use_self { struct Foo {} impl Foo { fn new() -> Foo { Foo {} } fn test() -> Foo { Foo::new() } } impl Default for Foo { fn default() -> Foo { Foo::new() } } } mod better { struct Foo {} impl Foo { fn new() -> Self { Self {} } fn test() -> Self { Self::new() } } impl Default for Foo { fn default() -> Self { Self::new() } } } //todo the lint does not handle lifetimed struct //the following module should trigger the lint on the third method only mod lifetimes { struct Foo<'a>{foo_str: &'a str} impl<'a> Foo<'a> { // Cannot use `Self` as return type, because the function is actually `fn foo<'b>(s: &'b str) -> Foo<'b>` fn foo(s: &str) -> Foo { Foo { foo_str: s } } // cannot replace with `Self`, because that's `Foo<'a>` fn bar() -> Foo<'static> { Foo { foo_str: "foo"} } // `Self` is applicable here fn clone(&self) -> Foo<'a> { Foo {foo_str: self.foo_str} } } } mod traits { #![cfg_attr(feature = "cargo-clippy", allow(boxed_local))] trait SelfTrait { fn refs(p1: &Self) -> &Self; fn ref_refs<'a>(p1: &'a &'a Self) -> &'a &'a Self; fn mut_refs(p1: &mut Self) -> &mut Self; fn nested(p1: Box, p2: (&u8, &Self)); fn vals(r: Self) -> Self; } #[derive(Default)] struct Bad; impl SelfTrait for Bad { fn refs(p1: &Bad) -> &Bad { p1 } fn ref_refs<'a>(p1: &'a &'a Bad) -> &'a &'a Bad { p1 } fn mut_refs(p1: &mut Bad) -> &mut Bad { p1 } fn nested(_p1: Box, _p2: (&u8, &Bad)) { } fn vals(_: Bad) -> Bad { Bad::default() } } #[derive(Default)] struct Good; impl SelfTrait for Good { fn refs(p1: &Self) -> &Self { p1 } fn ref_refs<'a>(p1: &'a &'a Self) -> &'a &'a Self { p1 } fn mut_refs(p1: &mut Self) -> &mut Self { p1 } fn nested(_p1: Box, _p2: (&u8, &Self)) { } fn vals(_: Self) -> Self { Self::default() } } trait NameTrait { fn refs(p1: &u8) -> &u8; fn ref_refs<'a>(p1: &'a &'a u8) -> &'a &'a u8; fn mut_refs(p1: &mut u8) -> &mut u8; fn nested(p1: Box, p2: (&u8, &u8)); fn vals(p1: u8) -> u8; } // Using `Self` instead of the type name is OK impl NameTrait for u8 { fn refs(p1: &Self) -> &Self { p1 } fn ref_refs<'a>(p1: &'a &'a Self) -> &'a &'a Self { p1 } fn mut_refs(p1: &mut Self) -> &mut Self { p1 } fn nested(_p1: Box, _p2: (&Self, &Self)) { } fn vals(_: Self) -> Self { Self::default() } } // Check that self arg isn't linted impl Clone for Good { fn clone(&self) -> Self { // Note: Not linted and it wouldn't be valid // because "can't use `Self` as a constructor` Good } } } mod issue2894 { trait IntoBytes { fn into_bytes(&self) -> Vec; } // This should not be linted impl IntoBytes for u8 { fn into_bytes(&self) -> Vec { vec![*self] } } }