Trait SingleAttributeParser

pub(crate) trait SingleAttributeParser: 'static {
    const PATH: &'static [Symbol];

    // Required methods
    fn on_duplicate(cx: &AcceptContext<'_>, first_span: Span);
    fn convert(
        cx: &AcceptContext<'_>,
        args: &ArgParser<'_>,
    ) -> Option<AttributeKind>;
}

Alternative to AttributeParser that automatically handles state management. A slightly simpler and more restricted way to convert attributes. Assumes that an attribute can only appear a single time on an item, and errors when it sees more.

Single<T> where T: SingleAttributeParser implements AttributeParser.

SingleAttributeParser can only convert attributes one-to-one, and cannot combine multiple attributes together like is necessary for #[stable()] and #[unstable()] for example.

Required Associated Constants

const PATH: &'static [Symbol]

Required Methods

fn on_duplicate(cx: &AcceptContext<'_>, first_span: Span)

Caled when a duplicate attribute is found.

first_span is the span of the first occurrence of this attribute.

fn convert( cx: &AcceptContext<'_>, args: &ArgParser<'_>, ) -> Option<AttributeKind>

Converts a single syntactical attribute to a single semantic attribute, or AttributeKind

Dyn Compatibility

This trait is not dyn compatible.

In older versions of Rust, dyn compatibility was called "object safety", so this trait is not object safe.

Implementors

impl SingleAttributeParser for DeprecationParser

const PATH: &'static [Symbol]

impl SingleAttributeParser for RustcMacroEdition2021Parser

const PATH: &'static [Symbol]

impl SingleAttributeParser for ConstStabilityIndirectParser

const PATH: &'static [Symbol]

impl SingleAttributeParser for TransparencyParser

const PATH: &'static [Symbol]