Struct SubtreeSkip 

pub struct SubtreeSkip { /* private fields */ }

A [Checker::should_skip_subtree] verdict, plus the following nodes it also answers for.

Most verdicts are about one node and carry no reach. The exception is a verdict a classifier can only reach by reading a run of siblings: Rust’s #[…] rows all decorate the same item, so they all get the same answer, and re-deriving it per row is O(run) work done run times. A run of 3 * depth attributes under a parent wide enough to stay inside the forward attribute-scan budget made that quadratic — 5.2 s at depth 2 000, against 0.05 s with exclude_tests off (#1446). Reporting the reach lets the walker ask the classifier once per run.

Soundness

The reach is a byte offset, and the walk visits nodes in non-decreasing start_byte order, so “starts before it” is a state the walker can test in O(1) and can never re-enter. A claim is sound when every node the walk visits inside the reach genuinely has the reported verdict.

“Visits” is the load-bearing word, and it cuts the obligation in two. A SKIP reach need only hold for the nodes it skips, since a skipped node’s descendants are never pushed. A RETAIN reach carries the heavier claim: the members’ descendants are walked, so it must be right for them too.

Implementations

impl SubtreeSkip

pub const RETAIN: Self

Keep this node. Answers for nothing else.

pub const SKIP: Self

Elide this node and its descendants. Answers for nothing else.

pub const fn of(skipped: bool) -> Self

Self::SKIP or Self::RETAIN, from a predicate’s answer.

pub const fn covering_through(self, byte: usize) -> Self

Extend this verdict to every node that starts before byte.

The caller is asserting that it read far enough to answer for all of them — see the soundness note on the type.

pub const fn is_skipped(self) -> bool

Whether this node and its descendants are elided.

pub const fn answers_for(self, start_byte: usize) -> bool

Whether this verdict already answers for a node starting at start_byte, so the classifier need not be asked again.

Trait Implementations

impl Clone for SubtreeSkip

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 SubtreeSkip

impl Debug for SubtreeSkip

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

Formats the value using the given formatter.

impl Eq for SubtreeSkip

impl PartialEq for SubtreeSkip

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

Equality operator ==.

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

Inequality operator !=.

impl StructuralPartialEq for SubtreeSkip