Enum Predicate

enum Predicate {
    Flag(Flag),
    Match(NameValue),
    Not(Box<Predicate>),
    All(Vec<Predicate>),
    Any(Vec<Predicate>),
}

Predicate(s) in #[rustc_on_unimplemented]’s on filter. See OnUnimplementedCondition.

It is similar to the predicate in the cfg attribute, and may contain nested predicates.

Variants

Flag(Flag)

A condition like on(crate_local).

Match(NameValue)

A match, like on(Rhs = "Whatever").

Not(Box<Predicate>)

Negation, like on(not($pred)).

All(Vec<Predicate>)

True if all predicates are true, like on(all($a, $b, $c)).

Any(Vec<Predicate>)

True if any predicate is true, like on(any($a, $b, $c)).

Implementations

impl Predicate

fn parse( input: &MetaItemInner, generics: &[Symbol], ) -> Result<Self, InvalidOnClause>

fn parse_sequence( sequence: &[MetaItemInner], generics: &[Symbol], ) -> Result<Vec<Self>, InvalidOnClause>

fn eval(&self, eval: &mut impl FnMut(FlagOrNv<'_>) -> bool) -> bool

Trait Implementations

impl Debug for Predicate

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

Formats the value using the given formatter.

Layout

Note: Most layout information is completely unstable and may even differ between compilations. The only exception is types with certain repr(...) attributes. Please see the Rust Reference's “Type Layout” chapter for details on type layout guarantees.

Size: 32 bytes

Size for each variant:

• Flag: 9 bytes
• Match: 32 bytes
• Not: 16 bytes
• All: 32 bytes
• Any: 32 bytes