Enum InterpEvalError 

pub enum InterpEvalError {
    Unevaluable,
    NonFinite,
}

Why eval_interp_checked could not produce a usable number.

Variants

Unevaluable

An unbound symbol or an expression form the interpreter doesn’t support — the same condition under which eval_interp returns None.

NonFinite

The interpreter produced NaN or ±inf. Under plain IEEE-754 arithmetic this happens for e.g. 0^-1 or 0 * inf, which is what (x²-1)/(x-1) reduces to at x = 1: the numerator vanishes, the denominator’s reciprocal blows up, and 0 * inf = NaN. That is not a number the caller should treat as the value of the expression at that point — the expression is undefined there (the value 2 is the limit as x → 1, obtained only after an explicit cancel()).

Trait Implementations

impl Clone for InterpEvalError

fn clone(&self) -> InterpEvalError

Returns a duplicate of the value.

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

Performs copy-assignment from source.

impl Copy for InterpEvalError

impl Debug for InterpEvalError

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

Formats the value using the given formatter.

impl Display for InterpEvalError

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

Formats the value using the given formatter.

impl Eq for InterpEvalError

impl Error for InterpEvalError

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 InterpEvalError

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

Equality operator ==.

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

Inequality operator !=.

impl StructuralPartialEq for InterpEvalError