Struct SyntaxContext

pub struct SyntaxContext(u32);

A SyntaxContext represents a chain of pairs (ExpnId, Transparency) named “marks”.

Tuple Fields

0: u32

Implementations

impl SyntaxContext

pub const fn root() -> Self

pub const fn is_root(self) -> bool

pub(crate) const fn as_u32(self) -> u32

pub(crate) const fn from_u32(raw: u32) -> SyntaxContext

pub(crate) const fn from_u16(raw: u16) -> SyntaxContext

pub fn apply_mark( self, expn_id: ExpnId, transparency: Transparency, ) -> SyntaxContext

Extend a syntax context with a given expansion and transparency.

pub fn remove_mark(&mut self) -> ExpnId

Pulls a single mark off of the syntax context. This effectively moves the context up one macro definition level. That is, if we have a nested macro definition as follows:

macro_rules! f {
   macro_rules! g {
       ...
   }
}

and we have a SyntaxContext that is referring to something declared by an invocation of g (call it g1), calling remove_mark will result in the SyntaxContext for the invocation of f that created g1. Returns the mark that was removed.

pub fn marks(self) -> Vec<(ExpnId, Transparency)>

pub fn adjust(&mut self, expn_id: ExpnId) -> Option<ExpnId>

Adjust this context for resolution in a scope created by the given expansion. For example, consider the following three resolutions of f:

#![feature(decl_macro)]
mod foo { pub fn f() {} } // `f`'s `SyntaxContext` is empty.
m!(f);
macro m($f:ident) {
    mod bar {
        pub fn f() {} // `f`'s `SyntaxContext` has a single `ExpnId` from `m`.
        pub fn $f() {} // `$f`'s `SyntaxContext` is empty.
    }
    foo::f(); // `f`'s `SyntaxContext` has a single `ExpnId` from `m`
    //^ Since `mod foo` is outside this expansion, `adjust` removes the mark from `f`,
    //| and it resolves to `::foo::f`.
    bar::f(); // `f`'s `SyntaxContext` has a single `ExpnId` from `m`
    //^ Since `mod bar` not outside this expansion, `adjust` does not change `f`,
    //| and it resolves to `::bar::f`.
    bar::$f(); // `f`'s `SyntaxContext` is empty.
    //^ Since `mod bar` is not outside this expansion, `adjust` does not change `$f`,
    //| and it resolves to `::bar::$f`.
}

This returns the expansion whose definition scope we use to privacy check the resolution, or None if we privacy check as usual (i.e., not w.r.t. a macro definition scope).

pub(crate) fn normalize_to_macros_2_0_and_adjust( &mut self, expn_id: ExpnId, ) -> Option<ExpnId>

Like SyntaxContext::adjust, but also normalizes self to macros 2.0.

pub(crate) fn glob_adjust( &mut self, expn_id: ExpnId, glob_span: Span, ) -> Option<Option<ExpnId>>

Adjust this context for resolution in a scope created by the given expansion via a glob import with the given SyntaxContext. For example:

#![feature(decl_macro)]
m!(f);
macro m($i:ident) {
    mod foo {
        pub fn f() {} // `f`'s `SyntaxContext` has a single `ExpnId` from `m`.
        pub fn $i() {} // `$i`'s `SyntaxContext` is empty.
    }
    n!(f);
    macro n($j:ident) {
        use foo::*;
        f(); // `f`'s `SyntaxContext` has a mark from `m` and a mark from `n`
        //^ `glob_adjust` removes the mark from `n`, so this resolves to `foo::f`.
        $i(); // `$i`'s `SyntaxContext` has a mark from `n`
        //^ `glob_adjust` removes the mark from `n`, so this resolves to `foo::$i`.
        $j(); // `$j`'s `SyntaxContext` has a mark from `m`
        //^ This cannot be glob-adjusted, so this is a resolution error.
    }
}

This returns None if the context cannot be glob-adjusted. Otherwise, it returns the scope to use when privacy checking (see adjust for details).

pub(crate) fn reverse_glob_adjust( &mut self, expn_id: ExpnId, glob_span: Span, ) -> Option<Option<ExpnId>>

Undo glob_adjust if possible:

if let Some(privacy_checking_scope) = self.reverse_glob_adjust(expansion, glob_ctxt) {
    assert!(self.glob_adjust(expansion, glob_ctxt) == Some(privacy_checking_scope));
}

pub fn hygienic_eq(self, other: SyntaxContext, expn_id: ExpnId) -> bool

pub fn normalize_to_macros_2_0(self) -> SyntaxContext

pub fn normalize_to_macro_rules(self) -> SyntaxContext

pub fn outer_expn(self) -> ExpnId

pub fn outer_expn_data(self) -> ExpnData

ctxt.outer_expn_data() is equivalent to but faster than ctxt.outer_expn().expn_data().

fn outer_mark(self) -> (ExpnId, Transparency)

pub(crate) fn dollar_crate_name(self) -> Symbol

pub fn edition(self) -> Edition

Trait Implementations

impl Clone for SyntaxContext

fn clone(&self) -> SyntaxContext

Returns a copy of the value.

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

Performs copy-assignment from source.

impl Debug for SyntaxContext

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

Formats the value using the given formatter.

impl<D: SpanDecoder> Decodable<D> for SyntaxContext

fn decode(s: &mut D) -> SyntaxContext

impl<E: SpanEncoder> Encodable<E> for SyntaxContext

fn encode(&self, s: &mut E)

impl Hash for SyntaxContext

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<CTX: HashStableContext> HashStable<CTX> for SyntaxContext

fn hash_stable(&self, ctx: &mut CTX, hasher: &mut StableHasher)

impl PartialEq for SyntaxContext

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

Tests for self and other values to be equal, and is used by ==.

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

Tests for !=. The default implementation is almost always sufficient, and should not be overridden without very good reason.

impl Copy for SyntaxContext

impl Eq for SyntaxContext

impl !Ord for SyntaxContext

impl !PartialOrd for SyntaxContext

impl StructuralPartialEq for SyntaxContext

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: 4 bytes