Enum PredicateFailure 

#[non_exhaustive]
pub enum PredicateFailure {
    EmptyAttributeMask,
    EmptyNameSet,
}

Why a query-by-example clause was rejected.

Both cases describe a clause that would silently match everything. Rejecting them turns a likely caller mistake into a reported error rather than an invisible match-all.

Variants (Non-exhaustive)

Non-exhaustive enums could have additional variants added in future. Therefore, when matching against variants of non-exhaustive enums, an extra wildcard arm must be added to account for any future variants.

EmptyAttributeMask

An attribute mask was zero. Every bit of an empty mask is both set and clear, so the clause is vacuous either way round.

EmptyNameSet

A name-pattern set was empty. It matches nothing, and its negation matches everything.

Trait Implementations

impl Clone for PredicateFailure

fn clone(&self) -> PredicateFailure

Returns a duplicate of the value.

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

Performs copy-assignment from source.

impl Copy for PredicateFailure

impl Debug for PredicateFailure

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

Formats the value using the given formatter.

impl Eq for PredicateFailure

impl Hash for PredicateFailure

fn hash<__H: Hasher>(&self, state: &mut __H)

Feeds this value into the given Hasher.

fn hash_slice<H>(data: &[Self], state: &mut H)

where H: Hasher, Self: Sized,

Feeds a slice of this type into the given Hasher.

impl PartialEq for PredicateFailure

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

Equality operator ==.

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

Inequality operator !=.

impl StructuralPartialEq for PredicateFailure