RS.CLIPPY.DERIVED_HASH_WITH_MANUAL_EQ

Deriving `Hash` but implementing `PartialEq` explicitly

This checker is a Clippy lint created by The Rust Project Contributors. The documentation shown here is a copy of the original documentation for: derived_hash_with_manual_eq. Copyright ©2025 The Rust Team. All rights reserved.

What it does

Lints against manual PartialEq implementations for types with a derived Hash implementation.

Why is this bad?

The implementation of these traits must agree (for example for use with HashMap) so it's probably a bad idea to use a default-generated Hash implementation with an explicitly defined PartialEq. In particular, the following must hold for any type:

k1 == k2 ⇒ hash(k1) == hash(k2)

Example

#[derive(Hash)]
struct Foo;

impl PartialEq for Foo {
    ...
}

Past names

derive_hash_xor_eq