pub struct SyntaxContext(u32);
Expand description

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

Tuple Fields§

§0: u32

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impl SyntaxContext

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pub const fn root() -> Self

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

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

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

Extend a syntax context with a given expansion and transparency.

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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.

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

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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).

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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.

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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).

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

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pub fn normalize_to_macros_2_0(self) -> SyntaxContext

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pub fn normalize_to_macro_rules(self) -> SyntaxContext

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pub fn outer_expn(self) -> ExpnId

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pub fn outer_expn_data(self) -> ExpnData

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

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

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pub fn dollar_crate_name(self) -> Symbol

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pub fn edition(self) -> Edition

Trait Implementations§

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impl Clone for SyntaxContext

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fn clone(&self) -> SyntaxContext

Returns a copy of the value. Read more
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fn clone_from(&mut self, source: &Self)

Performs copy-assignment from source. Read more
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impl Debug for SyntaxContext

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

Formats the value using the given formatter. Read more
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impl<D: Decoder> Decodable<D> for SyntaxContext

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default fn decode(_: &mut D) -> Self

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

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default fn encode(&self, _: &mut E)

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impl Hash for SyntaxContext

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

Feeds this value into the given Hasher. Read more
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fn hash_slice<H>(data: &[Self], state: &mut H)where
    H: Hasher,
    Self: Sized,

Feeds a slice of this type into the given Hasher. Read more
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impl<CTX: HashStableContext> HashStable<CTX> for SyntaxContext

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

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impl Ord for SyntaxContext

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fn cmp(&self, other: &SyntaxContext) -> Ordering

This method returns an Ordering between self and other. Read more
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fn max(self, other: Self) -> Selfwhere
    Self: Sized,

Compares and returns the maximum of two values. Read more
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fn min(self, other: Self) -> Selfwhere
    Self: Sized,

Compares and returns the minimum of two values. Read more
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fn clamp(self, min: Self, max: Self) -> Selfwhere
    Self: Sized + PartialOrd<Self>,

Restrict a value to a certain interval. Read more
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impl PartialEq<SyntaxContext> for SyntaxContext

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

This method tests for self and other values to be equal, and is used by ==.
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fn ne(&self, other: &Rhs) -> bool

This method tests for !=. The default implementation is almost always sufficient, and should not be overridden without very good reason.
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impl PartialOrd<SyntaxContext> for SyntaxContext

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fn partial_cmp(&self, other: &SyntaxContext) -> Option<Ordering>

This method returns an ordering between self and other values if one exists. Read more
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fn lt(&self, other: &Rhs) -> bool

This method tests less than (for self and other) and is used by the < operator. Read more
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fn le(&self, other: &Rhs) -> bool

This method tests less than or equal to (for self and other) and is used by the <= operator. Read more
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fn gt(&self, other: &Rhs) -> bool

This method tests greater than (for self and other) and is used by the > operator. Read more
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fn ge(&self, other: &Rhs) -> bool

This method tests greater than or equal to (for self and other) and is used by the >= operator. Read more
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impl Copy for SyntaxContext

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impl Eq for SyntaxContext

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impl StructuralEq for SyntaxContext

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impl StructuralPartialEq for SyntaxContext

Auto Trait Implementations§

Blanket Implementations§

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impl<T> Any for Twhere
    T: 'static + ?Sized,

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fn type_id(&self) -> TypeId

Gets the TypeId of self. Read more
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impl<T> Borrow<T> for Twhere
    T: ?Sized,

const: unstable · source§

fn borrow(&self) -> &T

Immutably borrows from an owned value. Read more
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impl<T> BorrowMut<T> for Twhere
    T: ?Sized,

const: unstable · source§

fn borrow_mut(&mut self) -> &mut T

Mutably borrows from an owned value. Read more
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impl<T> From<T> for T

const: unstable · source§

fn from(t: T) -> T

Returns the argument unchanged.

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impl<T, U> Into<U> for Twhere
    U: From<T>,

const: unstable · source§

fn into(self) -> U

Calls U::from(self).

That is, this conversion is whatever the implementation of From<T> for U chooses to do.

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impl<T> ToOwned for Twhere
    T: Clone,

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type Owned = T

The resulting type after obtaining ownership.
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fn to_owned(&self) -> T

Creates owned data from borrowed data, usually by cloning. Read more
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fn clone_into(&self, target: &mut T)

Uses borrowed data to replace owned data, usually by cloning. Read more
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impl<T, U> TryFrom<U> for Twhere
    U: Into<T>,

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type Error = Infallible

The type returned in the event of a conversion error.
const: unstable · source§

fn try_from(value: U) -> Result<T, <T as TryFrom<U>>::Error>

Performs the conversion.
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impl<T, U> TryInto<U> for Twhere
    U: TryFrom<T>,

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type Error = <U as TryFrom<T>>::Error

The type returned in the event of a conversion error.
const: unstable · source§

fn try_into(self) -> Result<U, <U as TryFrom<T>>::Error>

Performs the conversion.

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