Trait AssertNoneExt 

pub trait AssertNoneExt {
    // Required methods
    fn assert_none(self) -> Self;
    fn debug_assert_none(self) -> Self;
}

An extension trait to add the assertion_none methods.

Required Methods

fn assert_none(self) -> Self

Asserts the Option is None.

Panics

If it is Some, the method panics.

Examples

use chain_assertions::prelude::*;

let x: Option<i32> = None;
let x = x.assert_none().map(|x| x * 2);
assert_eq!(x, None);

use chain_assertions::prelude::*;

let x: Option<i32> = Some(21);
let _ = x.assert_none().map(|x| x * 2);
//        ^-- panics here

fn debug_assert_none(self) -> Self

Asserts the Option is None only in debug builds.

Panics

The method panics if all following conditions are satisfied:

• It is Some
• debug_assertions is enabled
• passthrough feature is disabled

Otherwise, the method returns self as is.

Examples

use chain_assertions::prelude::*;

let x: Option<i32> = None;
let x = x.debug_assert_none().map(|v| v * 2);
assert_eq!(x, None);

Dyn Compatibility

This trait is not dyn compatible.

In older versions of Rust, dyn compatibility was called "object safety", so this trait is not object safe.

Implementations on Foreign Types

impl<T> AssertNoneExt for Option<T>

where T: Debug,

fn assert_none(self) -> Self

fn debug_assert_none(self) -> Self

Implementors