rust/tests/ui/redundant_pattern_matching_option.fixed

#![warn(clippy::all)]
#![warn(clippy::redundant_pattern_matching)]
#![allow(
    unused_must_use,
    clippy::needless_bool,
    clippy::needless_if,
    clippy::match_like_matches_macro,
    clippy::equatable_if_let,
    clippy::if_same_then_else
)]
#![feature(let_chains, if_let_guard)]

fn issue_11174<T>(boolean: bool, maybe_some: Option<T>) -> bool {
    maybe_some.is_none() && (!boolean)
}

fn issue_11174_edge_cases<T>(boolean: bool, boolean2: bool, maybe_some: Option<T>) {
    let _ = maybe_some.is_none() && (boolean || boolean2); // guard needs parentheses
    let _ = match maybe_some { // can't use `matches!` here
                               // because `expr` metavars in macros don't allow let exprs
        None if let Some(x) = Some(0) && x > 5 => true,
        _ => false
    };
}

fn main() {
    if None::<()>.is_none() {}

    if Some(42).is_some() {}

    if Some(42).is_some() {
        foo();
    } else {
        bar();
    }

    while Some(42).is_some() {}

    while Some(42).is_none() {}

    while None::<()>.is_none() {}

    let mut v = vec![1, 2, 3];
    while v.pop().is_some() {
        foo();
    }

    if None::<i32>.is_none() {}

    if Some(42).is_some() {}

    Some(42).is_some();

    None::<()>.is_none();

    let _ = None::<()>.is_none();

    let opt = Some(false);
    let _ = if opt.is_some() { true } else { false };

    issue6067();
    issue10726();
    issue10803();

    let _ = if gen_opt().is_some() {
        1
    } else if gen_opt().is_none() {
        2
    } else {
        3
    };

    if gen_opt().is_some() {}
}

fn gen_opt() -> Option<()> {
    None
}

fn foo() {}

fn bar() {}

// Methods that are unstable const should not be suggested within a const context, see issue #5697.
// However, in Rust 1.48.0 the methods `is_some` and `is_none` of `Option` were stabilized as const,
// so the following should be linted.
const fn issue6067() {
    if Some(42).is_some() {}

    if None::<()>.is_none() {}

    while Some(42).is_some() {}

    while None::<()>.is_none() {}

    Some(42).is_some();

    None::<()>.is_none();
}

#[allow(clippy::deref_addrof, dead_code, clippy::needless_borrow)]
fn issue7921() {
    if (&None::<()>).is_none() {}
    if (&None::<()>).is_none() {}
}

fn issue10726() {
    let x = Some(42);

    x.is_some();

    x.is_none();

    x.is_none();

    x.is_some();

    // Don't lint
    match x {
        Some(21) => true,
        _ => false,
    };
}

fn issue10803() {
    let x = Some(42);

    let _ = x.is_some();

    let _ = x.is_none();

    // Don't lint
    let _ = matches!(x, Some(16));
}