rust-clippy/tests/ui/match_expr_like_matches_macro.rs

// run-rustfix

#![warn(clippy::match_like_matches_macro)]
#![allow(unreachable_patterns, dead_code)]

fn main() {
    let x = Some(5);

    // Lint
    let _y = match x {
        Some(0) => true,
        _ => false,
    };

    // Lint
    let _w = match x {
        Some(_) => true,
        _ => false,
    };

    // Turn into is_none
    let _z = match x {
        Some(_) => false,
        None => true,
    };

    // Lint
    let _zz = match x {
        Some(r) if r == 0 => false,
        _ => true,
    };

    // Lint
    let _zzz = if let Some(5) = x { true } else { false };

    // No lint
    let _a = match x {
        Some(_) => false,
        _ => false,
    };

    // No lint
    let _ab = match x {
        Some(0) => false,
        _ => true,
        None => false,
    };

    enum E {
        A(u32),
        B(i32),
        C,
        D,
    }
    let x = E::A(2);
    {
        // lint
        let _ans = match x {
            E::A(_) => true,
            E::B(_) => true,
            _ => false,
        };
    }
    {
        // lint
        let _ans = match x {
            E::B(_) => false,
            E::C => false,
            _ => true,
        };
    }
    {
        // no lint
        let _ans = match x {
            E::A(_) => false,
            E::B(_) => false,
            E::C => true,
            _ => true,
        };
    }
    {
        // no lint
        let _ans = match x {
            E::A(_) => true,
            E::B(_) => false,
            E::C => false,
            _ => true,
        };
    }
    {
        // no lint
        let _ans = match x {
            E::A(a) if a < 10 => false,
            E::B(a) if a < 10 => false,
            _ => true,
        };
    }
    {
        // no lint
        let _ans = match x {
            E::A(_) => false,
            E::B(a) if a < 10 => false,
            _ => true,
        };
    }
    {
        // no lint
        let _ans = match x {
            E::A(a) => a == 10,
            E::B(_) => false,
            _ => true,
        };
    }
    {
        // no lint
        let _ans = match x {
            E::A(_) => false,
            E::B(_) => true,
            _ => false,
        };
    }

    {
        // should print "z" in suggestion (#6503)
        let z = &Some(3);
        let _z = match &z {
            Some(3) => true,
            _ => false,
        };
    }

    {
        // this could also print "z" in suggestion..?
        let z = Some(3);
        let _z = match &z {
            Some(3) => true,
            _ => false,
        };
    }

    {
        enum AnEnum {
            X,
            Y,
        }

        fn foo(_x: AnEnum) {}

        fn main() {
            let z = AnEnum::X;
            // we can't remove the reference here!
            let _ = match &z {
                AnEnum::X => true,
                _ => false,
            };
            foo(z);
        }
    }

    {
        struct S(i32);

        fn fun(_val: Option<S>) {}
        let val = Some(S(42));
        // we need the reference here because later val is consumed by fun()
        let _res = match &val {
            &Some(ref _a) => true,
            _ => false,
        };
        fun(val);
    }

    {
        struct S(i32);

        fn fun(_val: Option<S>) {}
        let val = Some(S(42));
        let _res = match &val {
            &Some(ref _a) => true,
            _ => false,
        };
        fun(val);
    }
}