Struct OptionError 

pub struct OptionError {
    pub kind: OptionErrorKind,
    pub token: usize,
}

What: One refusal, with the index of the token that caused it. Why: A diagnostic can name the exact argument without this module rendering text for it.

In TS you’d write (pseudocode):

class OptionError extends Error { kind: OptionErrorKind; token: number }

Fields

kind: OptionErrorKind

The refusal category.

token: usize

Index of the offending token within the region.

Trait Implementations

impl Clone for OptionError

fn clone(&self) -> Self

Returns a duplicate of the value.

fn clone_from(&mut self, source: &Self)

Performs copy-assignment from source.

impl Copy for OptionError

impl Debug for OptionError

fn fmt(&self, f: &mut Formatter<'_>) -> Result

Formats the value using the given formatter.

impl Display for OptionError

What: impl std::fmt::Display for OptionError supplies Rust’s “print me” interface. Why: Callers can show the refusal with ordinary formatting.

In TS you’d write (pseudocode):

toString(): string { return `${kind} at argument ${token}`; }

fn fmt(&self, formatter: &mut Formatter<'_>) -> Result

&self borrows the error read-only; &mut lends the formatter for writing.

impl Eq for OptionError

impl Error for OptionError

An empty impl marks the type as a standard error value for generic handling.

fn source(&self) -> Option<&(dyn Error + 'static)>

Returns the lower-level source of this error, if any.

fn description(&self) -> &str

👎Deprecated since 1.42.0:

use the Display impl or to_string()

fn cause(&self) -> Option<&dyn Error>

👎Deprecated since 1.33.0:

replaced by Error::source, which can support downcasting

fn provide<'a>(&'a self, request: &mut Request<'a>)

🔬This is a nightly-only experimental API. (error_generic_member_access)

Provides type-based access to context intended for error reports.

impl PartialEq for OptionError

fn eq(&self, other: &Self) -> bool

Equality operator ==.

fn ne(&self, other: &Rhs) -> bool

Inequality operator !=.

impl StructuralPartialEq for OptionError