src/tools/clippy/tests/ui/manual_assert_eq.rs

//@aux-build:proc_macros.rs
#![warn(clippy::manual_assert_eq)]
#![expect(clippy::assertions_on_constants, clippy::eq_op)]

fn main() {
    let a = "a";
    assert!(a == "a".to_ascii_lowercase());
    //~^ manual_assert_eq
    assert!(a != "a".to_ascii_uppercase());
    //~^ manual_assert_eq
    debug_assert!(a == "a".to_ascii_lowercase());
    //~^ manual_assert_eq
    debug_assert!(a != "a".to_ascii_uppercase());
    //~^ manual_assert_eq

    // macros
    let v = vec![];
    assert!(v == vec![1, 2, 3]);
    //~^ manual_assert_eq
    assert!(vec![1, 2, 3] == v);
    //~^ manual_assert_eq
    assert!(vec![1] == vec![1, 2, 3]);
    //~^ manual_assert_eq

    // Don't lint: has assert message
    assert!(a == "a".to_ascii_lowercase(), "{a}");
    assert!(a == "a".to_ascii_lowercase(), "a==a");
    assert!(a == "a".to_ascii_lowercase(), "{a}==a");
    assert!(a != "a".to_ascii_uppercase(), "a!=A");
    debug_assert!(a == "a".to_ascii_lowercase(), "a==a");
    debug_assert!(a != "a".to_ascii_uppercase(), "a!=A");

    // Don't lint: `!=`, and at least one of the sides is a constant value
    assert!(a != "A");
    assert!("A" != a);
    assert!("A" != "A");

    // Don't lint: comparison of ptrs
    fn cmp_ptrs(a: *const u8, b: *const u8) {
        assert!(a == b);
    }

    // Don't lint: one of the sides isn't `Debug`
    {
        #[derive(PartialEq)]
        struct NotDebug;

        #[derive(PartialEq)]
        struct NotDebug2;

        impl PartialEq<NotDebug2> for NotDebug {
            fn eq(&self, other: &NotDebug2) -> bool {
                unimplemented!()
            }
        }
        impl PartialEq<NotDebug> for NotDebug2 {
            fn eq(&self, other: &NotDebug) -> bool {
                unimplemented!()
            }
        }

        #[derive(Debug)]
        struct IsDebug;

        impl PartialEq<IsDebug> for NotDebug {
            fn eq(&self, other: &IsDebug) -> bool {
                unimplemented!()
            }
        }
        impl PartialEq<NotDebug> for IsDebug {
            fn eq(&self, other: &NotDebug) -> bool {
                unimplemented!()
            }
        }

        let nd = NotDebug;
        assert!(nd == nd);

        let nd2 = NotDebug2;
        assert!(nd == nd2);
        assert!(nd2 == nd);

        let id = IsDebug;
        assert!(id == nd);
        assert!(nd == id);
    }

    // Don't lint: in const context
    const {
        assert!(5 == 2 + 3);
    }

    // Don't lint: in external macro
    {
        // NOTE: this only works because `root_macro_call_first_node` returns `external!`,
        // which then gets rejected by the macro name check
        proc_macros::external!(assert!('a' == 'b'));
        proc_macros::external!({
            let some_padding_before = 'a';
            assert!('a' == 'b');
            let some_padding_after = 'b';
        });

        // .. which also means that the following is _technically_ a FN -- but surely no one would write
        // code like this (diverging/unit expression as a child expression of a macro call)
        vec![(), assert!('a' == 'b'), ()];
    }
}

// Don't lint: in const context
const _: () = {
    assert!(8 == (7 + 1));
};