Struct LuaLClosure 

pub struct LuaLClosure {
    pub proto: GcRef<LuaProto>,
    pub upvals: Box<[Cell<GcRef<UpVal>>]>,
}

Fields

proto: GcRef<LuaProto>

upvals: Box<[Cell<GcRef<UpVal>>]>

Each upvalue slot is held in a Cell so that debug.upvaluejoin can replace an entry with another closure’s slot without rebuilding the (shared) closure. GcRef<UpVal> is Copy (thin wrapper over Gc<UpVal>), so a plain Cell is sufficient and skips RefCell borrow tracking on every upvalue read — critical for the upvalue_get hot path.

The slice is Box<[_]>, not Vec<_>: the upvalue count is fixed at closure creation (proto.upvalues.len()) and never grows or shrinks afterwards (set_upval is a Cell::set into an existing slot, not a resize). Dropping the Vec capacity word shrinks LuaLClosure by one pointer and makes buffer_bytes an exact GC-accounting figure.

Implementations

impl LuaLClosure

pub fn placeholder() -> Self

pub fn upval(&self, i: usize) -> GcRef<UpVal>

Returns the upvalue slot at index i. Cheap (Copy of a one-pointer GcRef<UpVal>).

pub fn set_upval(&self, i: usize, new: GcRef<UpVal>)

Replaces the upvalue slot at index i with new. Used by debug.upvaluejoin to share an upvalue between two closures.

pub fn buffer_bytes(&self) -> usize

Bytes owned outside the GcBox header/object allocation.

Box<[_]> has no separate capacity; len is the exact slot count, which is also the faithful GC-accounting figure.

Trait Implementations

impl Debug for LuaLClosure

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

Formats the value using the given formatter.

impl Trace for LuaLClosure

LuaLClosure — Lua closure carrying a Proto and its captured upvalues.

fn type_name(&self) -> &'static str

Concrete Rust type name for diagnostic/testC telemetry (Heap::type_name_count). Collector behavior must not branch on this. The default covers container blanket impls, which are never GC-boxed directly; concrete runtime types override it with std::any::type_name::<Self>().

fn trace(&self, m: &mut Marker)