[][src]Struct rustc_span::span_encoding::Span

pub struct Span {
    base_or_index: u32,
    len_or_tag: u16,
    ctxt_or_zero: u16,
}

A compressed span.

SpanData is 12 bytes, which is a bit too big to stick everywhere. Span is a form that only takes up 8 bytes, with less space for the length and context. The vast majority (99.9%+) of SpanData instances will fit within those 8 bytes; any SpanData whose fields don't fit into a Span are stored in a separate interner table, and the Span will index into that table. Interning is rare enough that the cost is low, but common enough that the code is exercised regularly.

An earlier version of this code used only 4 bytes for Span, but that was slower because only 80--90% of spans could be stored inline (even less in very large crates) and so the interner was used a lot more.

Inline (compressed) format:

Interned format:

The inline form uses 0 for the tag value (rather than 1) so that we don't need to mask out the tag bit when getting the length, and so that the dummy span can be all zeroes.

Notes about the choice of field sizes:

Fields

base_or_index: u32len_or_tag: u16ctxt_or_zero: u16

Implementations

impl Span[src]

pub fn fresh_expansion(self, expn_data: ExpnData) -> Span[src]

Creates a fresh expansion with given properties. Expansions are normally created by macros, but in some cases expansions are created for other compiler-generated code to set per-span properties like allowed unstable features. The returned span belongs to the created expansion and has the new properties, but its location is inherited from the current span.

pub fn fresh_expansion_with_transparency(
    self,
    expn_data: ExpnData,
    transparency: Transparency
) -> Span
[src]

impl Span[src]

pub fn new(lo: BytePos, hi: BytePos, ctxt: SyntaxContext) -> Self[src]

pub fn data(self) -> SpanData[src]

impl Span[src]

pub fn lo(self) -> BytePos[src]

pub fn with_lo(self, lo: BytePos) -> Span[src]

pub fn hi(self) -> BytePos[src]

pub fn with_hi(self, hi: BytePos) -> Span[src]

pub fn ctxt(self) -> SyntaxContext[src]

pub fn with_ctxt(self, ctxt: SyntaxContext) -> Span[src]

pub fn is_dummy(self) -> bool[src]

Returns true if this is a dummy span with any hygienic context.

pub fn from_expansion(self) -> bool[src]

Returns true if this span comes from a macro or desugaring.

pub fn in_derive_expansion(self) -> bool[src]

Returns true if span originates in a derive-macro's expansion.

pub fn with_root_ctxt(lo: BytePos, hi: BytePos) -> Span[src]

pub fn shrink_to_lo(self) -> Span[src]

Returns a new span representing an empty span at the beginning of this span

pub fn shrink_to_hi(self) -> Span[src]

Returns a new span representing an empty span at the end of this span.

pub fn is_empty(&self) -> bool[src]

Returns true if hi == lo

pub fn substitute_dummy(self, other: Span) -> Span[src]

Returns self if self is not the dummy span, and other otherwise.

pub fn contains(self, other: Span) -> bool[src]

Returns true if self fully encloses other.

pub fn overlaps(self, other: Span) -> bool[src]

Returns true if self touches other.

pub fn source_equal(&self, other: &Span) -> bool[src]

Returns true if the spans are equal with regards to the source text.

Use this instead of == when either span could be generated code, and you only care that they point to the same bytes of source text.

pub fn trim_start(self, other: Span) -> Option<Span>[src]

Returns Some(span), where the start is trimmed by the end of other.

pub fn source_callsite(self) -> Span[src]

Returns the source span -- this is either the supplied span, or the span for the macro callsite that expanded to it.

pub fn parent(self) -> Option<Span>[src]

The Span for the tokens in the previous macro expansion from which self was generated, if any.

pub fn edition(self) -> Edition[src]

Edition of the crate from which this span came.

pub fn rust_2015(&self) -> bool[src]

pub fn rust_2018(&self) -> bool[src]

pub fn source_callee(self) -> Option<ExpnData>[src]

Returns the source callee.

Returns None if the supplied span has no expansion trace, else returns the ExpnData for the macro definition corresponding to the source callsite.

pub fn allows_unstable(&self, feature: Symbol) -> bool[src]

Checks if a span is "internal" to a macro in which #[unstable] items can be used (that is, a macro marked with #[allow_internal_unstable]).

pub fn is_desugaring(&self, kind: DesugaringKind) -> bool[src]

Checks if this span arises from a compiler desugaring of kind kind.

pub fn desugaring_kind(&self) -> Option<DesugaringKind>[src]

Returns the compiler desugaring that created this span, or None if this span is not from a desugaring.

pub fn allows_unsafe(&self) -> bool[src]

Checks if a span is "internal" to a macro in which unsafe can be used without triggering the unsafe_code lint

pub fn macro_backtrace(self) -> impl Iterator<Item = ExpnData>[src]

pub fn to(self, end: Span) -> Span[src]

Returns a Span that would enclose both self and end.

    ____             ___
    self lorem ipsum end
    ^^^^^^^^^^^^^^^^^^^^

pub fn between(self, end: Span) -> Span[src]

Returns a Span between the end of self to the beginning of end.

    ____             ___
    self lorem ipsum end
        ^^^^^^^^^^^^^

pub fn until(self, end: Span) -> Span[src]

Returns a Span from the beginning of self until the beginning of end.

    ____             ___
    self lorem ipsum end
    ^^^^^^^^^^^^^^^^^

pub fn from_inner(self, inner: InnerSpan) -> Span[src]

pub fn with_def_site_ctxt(self, expn_id: ExpnId) -> Span[src]

Equivalent of Span::def_site from the proc macro API, except that the location is taken from the self span.

pub fn with_call_site_ctxt(&self, expn_id: ExpnId) -> Span[src]

Equivalent of Span::call_site from the proc macro API, except that the location is taken from the self span.

pub fn with_mixed_site_ctxt(&self, expn_id: ExpnId) -> Span[src]

Equivalent of Span::mixed_site from the proc macro API, except that the location is taken from the self span.

pub fn with_ctxt_from_mark(
    self,
    expn_id: ExpnId,
    transparency: Transparency
) -> Span
[src]

Produces a span with the same location as self and context produced by a macro with the given ID and transparency, assuming that macro was defined directly and not produced by some other macro (which is the case for built-in and procedural macros).

pub fn apply_mark(self, expn_id: ExpnId, transparency: Transparency) -> Span[src]

pub fn remove_mark(&mut self) -> ExpnId[src]

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

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

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

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

pub fn normalize_to_macros_2_0(self) -> Span[src]

pub fn normalize_to_macro_rules(self) -> Span[src]

Trait Implementations

impl Clone for Span[src]

impl Copy for Span[src]

impl Debug for Span[src]

impl<D: Decoder> Decodable<D> for Span[src]

impl Default for Span[src]

impl<E: Encoder> Encodable<E> for Span[src]

impl Eq for Span[src]

impl From<Span> for MultiSpan[src]

impl Hash for Span[src]

impl<CTX> HashStable<CTX> for Span where
    CTX: HashStableContext
[src]

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

Hashes a span in a stable way. We can't directly hash the span's BytePos fields (that would be similar to hashing pointers, since those are just offsets into the SourceMap). Instead, we hash the (file name, line, column) triple, which stays the same even if the containing SourceFile has moved within the SourceMap. Also note that we are hashing byte offsets for the column, not unicode codepoint offsets. For the purpose of the hash that's sufficient. Also, hashing filenames is expensive so we avoid doing it twice when the span starts and ends in the same file, which is almost always the case.

impl Ord for Span[src]

impl PartialEq<Span> for Span[src]

impl PartialOrd<Span> for Span[src]

impl !Send for Span[src]

impl StructuralEq for Span[src]

impl StructuralPartialEq for Span[src]

impl !Sync for Span[src]

Auto Trait Implementations

impl RefUnwindSafe for Span

impl Unpin for Span

impl UnwindSafe for Span

Blanket Implementations

impl<T> Any for T where
    T: 'static + ?Sized
[src]

impl<T> Borrow<T> for T where
    T: ?Sized
[src]

impl<T> BorrowMut<T> for T where
    T: ?Sized
[src]

impl<T> From<T> for T[src]

impl<T, U> Into<U> for T where
    U: From<T>, 
[src]

impl<T> ToOwned for T where
    T: Clone
[src]

type Owned = T

The resulting type after obtaining ownership.

impl<T, U> TryFrom<U> for T where
    U: Into<T>, 
[src]

type Error = Infallible

The type returned in the event of a conversion error.

impl<T, U> TryInto<U> for T where
    U: TryFrom<T>, 
[src]

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

The type returned in the event of a conversion error.