#![warn(clippy::map_identity)]
#![allow(clippy::needless_return)]

fn main() {
    let x: [u16; 3] = [1, 2, 3];
    // should lint
    let _: Vec<_> = x.iter().map(not_identity).collect();
    let _: Vec<_> = x.iter().collect();
    let _: Option<u8> = Some(3);
    let _: Result<i8, f32> = Ok(-3);
    // should not lint
    let _: Vec<_> = x.iter().map(|x| 2 * x).collect();
    let _: Vec<_> = x.iter().map(not_identity).map(|x| return x - 4).collect();
    let _: Option<u8> = None.map(|x: u8| x - 1);
    let _: Result<i8, f32> = Err(2.3).map(|x: i8| {
        return x + 3;
    });
    let _: Result<u32, u32> = Ok(1);
    let _: Result<u32, u32> = Ok(1).map_err(|a: u32| a * 42);
    // : u32 guides type inference
    let _ = Ok(1).map_err(|a: u32| a);
    let _ = Ok(1).map_err(std::convert::identity::<u32>);
}

fn not_identity(x: &u16) -> u16 {
    *x
}