core::option::NoneError - Rust
Description: API documentation for the Rust `NoneError` struct in crate `core`.
Keywords: rust, rustlang, rust-lang, NoneError

# Struct core::option::NoneError [−] [src]

    pub struct NoneError;

🔬 This is a nightly-only experimental API. (`try_trait` #42327)

The error type that results from applying the try operator (`?`) to a `None` value. If you wish to allow `x?` (where `x` is an `Option<T>`) to be converted into your error type, you can implement `impl From<NoneError>` for `YourErrorType`. In that case, `x?` within a function that returns `Result<_, YourErrorType>` will translate a `None` value into an `Err` result.

## Trait Implementations

### `impl Clone for NoneError`
[src]

#### `fn clone(&self) -> NoneError`
[src]

Returns a copy of the value. Read more

#### `fn clone_from(&mut self, source: &Self)`
1.0.0
[src]

Performs copy-assignment from `source`. Read more

### `impl Copy for NoneError`
[src]

### `impl PartialEq for NoneError`
[src]

#### `fn eq(&self, __arg_0: &NoneError) -> bool`
[src]

This method tests for `self` and `other` values to be equal, and is used by `==`. Read more

#### `fn ne(&self, other: &Rhs) -> bool`
1.0.0
[src]

This method tests for `!=`.

### `impl PartialOrd for NoneError`
[src]

#### `fn partial_cmp(&self, __arg_0: &NoneError) -> Option<Ordering>`
[src]

This method returns an ordering between `self` and `other` values if one exists. Read more

#### `fn lt(&self, other: &Rhs) -> bool`
1.0.0
[src]

This method tests less than (for `self` and `other`) and is used by the `<` operator. Read more

#### `fn le(&self, other: &Rhs) -> bool`
1.0.0
[src]

This method tests less than or equal to (for `self` and `other`) and is used by the `<=` operator. Read more

#### `fn gt(&self, other: &Rhs) -> bool`
1.0.0
[src]

This method tests greater than (for `self` and `other`) and is used by the `>` operator. Read more

#### `fn ge(&self, other: &Rhs) -> bool`
1.0.0
[src]

This method tests greater than or equal to (for `self` and `other`) and is used by the `>=` operator. Read more

### `impl Eq for NoneError`
[src]

### `impl Ord for NoneError`
[src]

#### `fn cmp(&self, __arg_0: &NoneError) -> Ordering`
[src]

This method returns an `Ordering` between `self` and `other`. Read more

#### `fn max(self, other: Self) -> Self where
Self: Sized,`
1.21.0
[src]

Compares and returns the maximum of two values. Read more

#### `fn min(self, other: Self) -> Self where
Self: Sized,`
1.21.0
[src]

Compares and returns the minimum of two values. Read more

### `impl Debug for NoneError`
[src]

#### `fn fmt(&self, __arg_0: &mut Formatter) -> Result`
[src]

Formats the value using the given formatter. Read more

### `impl Hash for NoneError`
[src]

#### `fn hash<__H: Hasher>(&self, __arg_0: &mut __H)`
[src]

Feeds this value into the given [`Hasher`]. Read more

#### `fn hash_slice<H: Hasher>(data: &[Self], state: &mut H) where
Self: Sized,`
1.3.0
[src]

Feeds a slice of this type into the given [`Hasher`]. Read more

# Help

## Keyboard Shortcuts

?
  Show this help dialog
S
  Focus the search field
↑
  Move up in search results
↓
  Move down in search results
↹
  Switch tab
⏎
  Go to active search result
+ / -
  Collapse/expand all sections

## Search Tricks

Prefix searches with a type followed by a colon (e.g. `fn:`) to restrict the search to a given type.

Accepted types are: `fn`, `mod`, `struct`, `enum`, `trait`, `type`, `macro`, and `const`.

Search functions by type signature (e.g. `vec -> usize` or `* -> vec`)