rust/tests/ui/nonminimal_bool_methods.rs

#![allow(unused, clippy::diverging_sub_expression)]
#![warn(clippy::nonminimal_bool)]

fn methods_with_negation() {
    let a: Option<i32> = unimplemented!();
    let b: Result<i32, i32> = unimplemented!();
    let _ = a.is_some();
    let _ = !a.is_some();
    let _ = a.is_none();
    let _ = !a.is_none();
    let _ = b.is_err();
    let _ = !b.is_err();
    let _ = b.is_ok();
    let _ = !b.is_ok();
    let c = false;
    let _ = !(a.is_some() && !c);
    let _ = !(a.is_some() || !c);
    let _ = !(!c ^ c) || !a.is_some();
    let _ = (!c ^ c) || !a.is_some();
    let _ = !c ^ c || !a.is_some();
}

// Simplified versions of https://github.com/rust-lang/rust-clippy/issues/2638
// clippy::nonminimal_bool should only check the built-in Result and Some type, not
// any other types like the following.
enum CustomResultOk<E> {
    Ok,
    Err(E),
}
enum CustomResultErr<E> {
    Ok,
    Err(E),
}
enum CustomSomeSome<T> {
    Some(T),
    None,
}
enum CustomSomeNone<T> {
    Some(T),
    None,
}

impl<E> CustomResultOk<E> {
    pub fn is_ok(&self) -> bool {
        true
    }
}

impl<E> CustomResultErr<E> {
    pub fn is_err(&self) -> bool {
        true
    }
}

impl<T> CustomSomeSome<T> {
    pub fn is_some(&self) -> bool {
        true
    }
}

impl<T> CustomSomeNone<T> {
    pub fn is_none(&self) -> bool {
        true
    }
}

fn dont_warn_for_custom_methods_with_negation() {
    let res = CustomResultOk::Err("Error");
    // Should not warn and suggest 'is_err()' because the type does not
    // implement is_err().
    if !res.is_ok() {}

    let res = CustomResultErr::Err("Error");
    // Should not warn and suggest 'is_ok()' because the type does not
    // implement is_ok().
    if !res.is_err() {}

    let res = CustomSomeSome::Some("thing");
    // Should not warn and suggest 'is_none()' because the type does not
    // implement is_none().
    if !res.is_some() {}

    let res = CustomSomeNone::Some("thing");
    // Should not warn and suggest 'is_some()' because the type does not
    // implement is_some().
    if !res.is_none() {}
}

// Only Built-in Result and Some types should suggest the negated alternative
fn warn_for_built_in_methods_with_negation() {
    let res: Result<usize, usize> = Ok(1);
    if !res.is_ok() {}
    if !res.is_err() {}

    let res = Some(1);
    if !res.is_some() {}
    if !res.is_none() {}
}

#[allow(clippy::neg_cmp_op_on_partial_ord)]
fn dont_warn_for_negated_partial_ord_comparison() {
    let a: f64 = unimplemented!();
    let b: f64 = unimplemented!();
    let _ = !(a < b);
    let _ = !(a <= b);
    let _ = !(a > b);
    let _ = !(a >= b);
}

fn main() {}