Trait unwrap_none::UnwrapNone[−][src]

pub trait UnwrapNone {
    fn expect_none(self, msg: &str);

    fn unwrap_none(self);
}

Required methods

fn expect_none(self, msg: &str)[src]

Consumes self while expecting None and returning nothing.

Panics

Panics if the value is a Some, with a panic message including the passed message, and the content of the Some.

Examples

#![feature(option_expect_none)]

use std::collections::HashMap;
let mut squares = HashMap::new();
for i in -10..=10 {
    // This will not panic, since all keys are unique.
    squares.insert(i, i * i).expect_none("duplicate key");
}
ⓘ
#![feature(option_expect_none)]

use std::collections::HashMap;
let mut sqrts = HashMap::new();
for i in -10..=10 {
    // This will panic, since both negative and positive `i` will
    // insert the same `i * i` key, returning the old `Some(i)`.
    sqrts.insert(i * i, i).expect_none("duplicate key");
}

fn unwrap_none(self)[src]

Consumes self while expecting None and returning nothing.

Panics

Panics if the value is a Some, with a custom panic message provided by the Some’s value.

Examples

#![feature(option_unwrap_none)]

use std::collections::HashMap;
let mut squares = HashMap::new();
for i in -10..=10 {
    // This will not panic, since all keys are unique.
    squares.insert(i, i * i).unwrap_none();
}
ⓘ
#![feature(option_unwrap_none)]

use std::collections::HashMap;
let mut sqrts = HashMap::new();
for i in -10..=10 {
    // This will panic, since both negative and positive `i` will
    // insert the same `i * i` key, returning the old `Some(i)`.
    sqrts.insert(i * i, i).unwrap_none();
}
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Implementations on Foreign Types

impl<T> UnwrapNone for Option<T> where
    T: Debug, [src]

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Implementors

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