//@run-rustfix #![allow( unused, clippy::needless_if, clippy::redundant_clone, clippy::derive_partial_eq_without_eq )] // See #5700 // Define the types in each module to avoid trait impls leaking between modules. macro_rules! impl_types { () => { #[derive(PartialEq)] pub struct Owned; pub struct Borrowed; impl ToOwned for Borrowed { type Owned = Owned; fn to_owned(&self) -> Owned { Owned {} } } impl std::borrow::Borrow for Owned { fn borrow(&self) -> &Borrowed { static VALUE: Borrowed = Borrowed {}; &VALUE } } }; } // Only Borrowed == Owned is implemented mod borrowed_eq_owned { impl_types!(); impl PartialEq for Borrowed { fn eq(&self, _: &Owned) -> bool { true } } pub fn compare() { let owned = Owned {}; let borrowed = Borrowed {}; if borrowed == owned {} if borrowed == owned {} } } // Only Owned == Borrowed is implemented mod owned_eq_borrowed { impl_types!(); impl PartialEq for Owned { fn eq(&self, _: &Borrowed) -> bool { true } } fn compare() { let owned = Owned {}; let borrowed = Borrowed {}; if owned == borrowed {} if owned == borrowed {} } } mod issue_4874 { impl_types!(); // NOTE: PartialEq for T can't be implemented due to the orphan rules impl PartialEq for Borrowed where T: AsRef + ?Sized, { fn eq(&self, _: &T) -> bool { true } } impl std::fmt::Display for Borrowed { fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result { write!(f, "borrowed") } } fn compare() { let borrowed = Borrowed {}; if borrowed == "Hi" {} if borrowed == "Hi" {} } } fn main() {}