Enum Slot 

pub enum Slot {
    Agg(u32),
    AggSet(Vec<u32>),
    Other,
}

Abstract value at a stack or local slot during the analysis.

Per-path refinement (#463 follow-up — precision pass): a slot can hold a set of allocation sites, not just one, because two branches of an if/match can each push a distinct MakeRecord / MakeTuple value onto the stack and the join point’s “either- or” semantics must be modeled without losing tracking. The 3-variant shape keeps the singleton case zero-alloc — Slot::Agg is plain 8 bytes inline — and only branch-merges allocate.

Variants

Agg(u32)

Holds a single tracked aggregate (a record from Op::MakeRecord or a tuple from Op::MakeTuple) allocated at this pc. As long as every consumer reads this slot via a field / element read (GetField / GetElem), Pop, or a StoreLocal/LoadLocal round-trip, the site stays a stack-alloc candidate. The escape rules are identical for both aggregate kinds — only the codegen opcode differs — so the analysis tracks them with one variant keyed on the alloc pc.

AggSet(Vec<u32>)

Holds one of N tracked aggregates, depending on which branch reached this program point. Produced at join points where distinct Agg(p) and Agg(q) flow together; the set remains tracked across the merge so the eventual consumer (e.g. Return under Policy::RequestScope) decides whether any site leaks. Invariant: vec is sorted, dedup’d, length ≥ 2 — Slot::from_sites normalizes single-element / empty inputs.

Other

Anything else — primitives, already-escaped aggregates, values produced by ops we don’t model precisely. Treated as not-a-tracked-aggregate for escape purposes.

Trait Implementations

impl Clone for Slot

fn clone(&self) -> Slot

Returns a duplicate of the value.

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

Performs copy-assignment from source.

impl Debug for Slot

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

Formats the value using the given formatter.

impl Eq for Slot

impl Hash for Slot

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 PartialEq for Slot

fn eq(&self, other: &Slot) -> 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 StructuralPartialEq for Slot