Struct SyntaxContext 

pub struct SyntaxContext {
    private_use_as_methods_instead: u32 is 0..=536870911,
}

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

See https://rustc-dev-guide.rust-lang.org/macro-expansion.html for more explanation.

Fields

private_use_as_methods_instead: u32 is 0..=536870911

Implementations

impl SyntaxContext

pub const MAX_AS_U32: u32 = 0x1FFF_FFFF

Maximum value the index can take, as a u32.

pub const MAX: Self

Maximum value the index can take.

pub const ZERO: Self

Zero value of the index.

pub const fn from_usize(value: usize) -> Self

Creates a new index from a given usize.

Panics

Will panic if value exceeds MAX.

pub const fn from_u32(value: u32) -> Self

Creates a new index from a given u32.

Panics

Will panic if value exceeds MAX.

pub const fn from_u16(value: u16) -> Self

Creates a new index from a given u16.

Panics

Will panic if value exceeds MAX.

pub const unsafe fn from_u32_unchecked(value: u32) -> Self

Creates a new index from a given u32.

Safety

The provided value must be less than or equal to the maximum value for the newtype. Providing a value outside this range is undefined due to layout restrictions.

Prefer using from_u32.

pub const fn index(self) -> usize

Extracts the value of this index as a usize.

pub const fn as_u32(self) -> u32

Extracts the value of this index as a u32.

pub const fn as_usize(self) -> usize

Extracts the value of this index as a usize.

impl SyntaxContext

pub const fn root() -> SyntaxContext

pub const fn is_root(self) -> bool

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 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 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 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

See SyntaxContextData::outer_expn

pub fn outer_expn_data(self) -> ExpnData

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

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

pub fn edition(self) -> Edition

pub fn in_external_macro(self, sm: &SourceMap) -> bool

Returns whether this context originates in a foreign crate’s external macro.

This is used to test whether a lint should not even begin to figure out whether it should be reported on the current node.

impl SyntaxContext

fn stable_hash_internal( self, data: Option<&HygieneData>, hcx: &mut impl StableHashCtxt, hasher: &mut StableHasher, )

Trait Implementations

impl !Ord for SyntaxContext

impl !PartialOrd for SyntaxContext

impl Add<usize> for SyntaxContext

type Output = SyntaxContext

The resulting type after applying the + operator.

fn add(self, other: usize) -> Self

Performs the + operation.

impl AddAssign<usize> for SyntaxContext

fn add_assign(&mut self, other: usize)

Performs the += operation.

impl Clone for SyntaxContext

fn clone(&self) -> Self

Returns a duplicate of the value.

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

Performs copy-assignment from source.

impl Copy for SyntaxContext

impl Debug for SyntaxContext

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

Formats the value using the given formatter.

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

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

impl Default for SyntaxContext

fn default() -> Self

Returns the “default value” for a type.

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

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

impl Eq for SyntaxContext

impl From<SyntaxContext> for u32

fn from(v: SyntaxContext) -> u32

Converts to this type from the input type.

impl From<SyntaxContext> for usize

fn from(v: SyntaxContext) -> usize

Converts to this type from the input type.

impl From<u32> for SyntaxContext

fn from(value: u32) -> Self

Converts to this type from the input type.

impl From<usize> for SyntaxContext

fn from(value: usize) -> Self

Converts to this type from the input type.

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 HygieneRemapper<SyntaxContext> for SyntaxContextRemapper<'_>

fn len(&self) -> usize

fn first_non_det_index_mut(&mut self) -> &mut Option<SyntaxContext>

fn first_non_det_index(&self) -> u32

fn stable_hash( &self, ctxt: SyntaxContext, hcx: &mut impl StableHashCtxt, hasher: &mut StableHasher, )

fn commit_end_of_determinism(&mut self)

where T: From<u32>,

fn remapping_results<TRemappedKey>( &self, hcx: &mut impl StableHashCtxt, ) -> HygieneRemappingResults<T, TRemappedKey>

where T: RemappableIdx + From<u32>,

impl Idx for SyntaxContext

fn new(value: usize) -> Self

fn index(self) -> usize

fn increment_by(&mut self, amount: usize)

fn plus(self, amount: usize) -> Self

impl PartialEq for SyntaxContext

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

Equality operator ==.

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

Inequality operator !=.

impl StableHash for SyntaxContext

fn stable_hash<Hcx: StableHashCtxt>( &self, hcx: &mut Hcx, hasher: &mut StableHasher, )

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