Struct ShadowFrameGuard 

pub struct ShadowFrameGuard { /* private fields */ }

A frame claimed from Rust, released when dropped.

The RAII shape is what makes “write past your frame” unrepresentable from Rust: Self::set and Self::clear are bounds-checked against the width the frame was pushed with, and the only way to restore top is to drop the guard — so a frame cannot outlive its slots or be popped twice.

Implementations

impl ShadowFrameGuard

pub fn set(&mut self, index: usize, r: GcRef)

Root r in slot index.

Panics

If index is outside the frame. Writing another frame’s slot would make the collector’s view of that frame wrong, which is not a condition the caller could detect afterwards.

pub fn clear(&mut self, index: usize)

Un-root slot index. A dead slot must not keep its object reachable, and since swept storage is reusable a stale slot could name a live object of an entirely different type.

Panics

If index is outside the frame.

pub fn base_ptr(&self) -> *mut *mut GcHeader

This frame’s first slot, for a caller that wants to observe the slot memory the way generated code addresses it.

Trait Implementations

impl Drop for ShadowFrameGuard

fn drop(&mut self)

Executes the destructor for this type.

fn pin_drop(self: Pin<&mut Self>)

🔬This is a nightly-only experimental API. (pin_ergonomics)

Execute the destructor for this type, but different to Drop::drop, it requires self to be pinned.