Trait zerogc::GcSafe

pub unsafe trait GcSafe: Trace {
    const NEEDS_DROP: bool;
}

Indicates that a type can be safely allocated by a garbage collector.

Safety

Custom destructors must never reference garbage collected pointers. The garbage collector may have already freed the other objects before calling this type’s drop function.

Unlike java finalizers, this allows us to deallocate objects normally and avoids a second pass over the objects to check for resurrected objects.

Associated Constants

const NEEDS_DROP: bool

If this type needs a destructor run

This is usually equivalent to std::mem::needs_drop. However procedurally derived code can sometimes provide a no-op drop implementation (for safety), which would lead to a false positive with std::mem::needs_drop()

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Implementations on Foreign Types

impl GcSafe for i8

const NEEDS_DROP: bool

impl GcSafe for i16

const NEEDS_DROP: bool

impl GcSafe for i32

const NEEDS_DROP: bool

impl GcSafe for i64

const NEEDS_DROP: bool

impl GcSafe for isize

const NEEDS_DROP: bool

impl GcSafe for u8

const NEEDS_DROP: bool

impl GcSafe for u16

const NEEDS_DROP: bool

impl GcSafe for u32

const NEEDS_DROP: bool

impl GcSafe for u64

const NEEDS_DROP: bool

impl GcSafe for usize

const NEEDS_DROP: bool

impl GcSafe for f32

const NEEDS_DROP: bool

impl GcSafe for f64

const NEEDS_DROP: bool

impl GcSafe for bool

const NEEDS_DROP: bool

impl GcSafe for char

const NEEDS_DROP: bool

impl GcSafe for &'static str

const NEEDS_DROP: bool

impl<T> GcSafe for PhantomData<T>

const NEEDS_DROP: bool

impl GcSafe for ()

const NEEDS_DROP: bool

impl<I> GcSafe for (I,) where
    I: GcSafe,
    I: Trace, 

const NEEDS_DROP: bool

impl<H, I> GcSafe for (H, I) where
    H: GcSafe,
    I: GcSafe,
    H: Trace,
    I: Trace, 

const NEEDS_DROP: bool

impl<G, H, I> GcSafe for (G, H, I) where
    G: GcSafe,
    H: GcSafe,
    I: GcSafe,
    G: Trace,
    H: Trace,
    I: Trace, 

const NEEDS_DROP: bool

impl<F, G, H, I> GcSafe for (F, G, H, I) where
    F: GcSafe,
    G: GcSafe,
    H: GcSafe,
    I: GcSafe,
    F: Trace,
    G: Trace,
    H: Trace,
    I: Trace, 

const NEEDS_DROP: bool

impl<E, F, G, H, I> GcSafe for (E, F, G, H, I) where
    E: GcSafe,
    F: GcSafe,
    G: GcSafe,
    H: GcSafe,
    I: GcSafe,
    E: Trace,
    F: Trace,
    G: Trace,
    H: Trace,
    I: Trace, 

const NEEDS_DROP: bool

impl<D, E, F, G, H, I> GcSafe for (D, E, F, G, H, I) where
    D: GcSafe,
    E: GcSafe,
    F: GcSafe,
    G: GcSafe,
    H: GcSafe,
    I: GcSafe,
    D: Trace,
    E: Trace,
    F: Trace,
    G: Trace,
    H: Trace,
    I: Trace, 

const NEEDS_DROP: bool

impl<C, D, E, F, G, H, I> GcSafe for (C, D, E, F, G, H, I) where
    C: GcSafe,
    D: GcSafe,
    E: GcSafe,
    F: GcSafe,
    G: GcSafe,
    H: GcSafe,
    I: GcSafe,
    C: Trace,
    D: Trace,
    E: Trace,
    F: Trace,
    G: Trace,
    H: Trace,
    I: Trace, 

const NEEDS_DROP: bool

impl<B, C, D, E, F, G, H, I> GcSafe for (B, C, D, E, F, G, H, I) where
    B: GcSafe,
    C: GcSafe,
    D: GcSafe,
    E: GcSafe,
    F: GcSafe,
    G: GcSafe,
    H: GcSafe,
    I: GcSafe,
    B: Trace,
    C: Trace,
    D: Trace,
    E: Trace,
    F: Trace,
    G: Trace,
    H: Trace,
    I: Trace, 

const NEEDS_DROP: bool

impl<A, B, C, D, E, F, G, H, I> GcSafe for (A, B, C, D, E, F, G, H, I) where
    A: GcSafe,
    B: GcSafe,
    C: GcSafe,
    D: GcSafe,
    E: GcSafe,
    F: GcSafe,
    G: GcSafe,
    H: GcSafe,
    I: GcSafe,
    A: Trace,
    B: Trace,
    C: Trace,
    D: Trace,
    E: Trace,
    F: Trace,
    G: Trace,
    H: Trace,
    I: Trace, 

const NEEDS_DROP: bool

impl<T> GcSafe for [T; 0] where
    T: GcSafe,
    T: Trace, 

const NEEDS_DROP: bool

impl<T> GcSafe for [T; 1] where
    T: GcSafe,
    T: Trace, 

const NEEDS_DROP: bool

impl<T> GcSafe for [T; 2] where
    T: GcSafe,
    T: Trace, 

const NEEDS_DROP: bool

impl<T> GcSafe for [T; 3] where
    T: GcSafe,
    T: Trace, 

const NEEDS_DROP: bool

impl<T> GcSafe for [T; 4] where
    T: GcSafe,
    T: Trace, 

const NEEDS_DROP: bool

impl<T> GcSafe for [T; 5] where
    T: GcSafe,
    T: Trace, 

const NEEDS_DROP: bool

impl<T> GcSafe for [T; 6] where
    T: GcSafe,
    T: Trace, 

const NEEDS_DROP: bool

impl<T> GcSafe for [T; 7] where
    T: GcSafe,
    T: Trace, 

const NEEDS_DROP: bool

impl<T> GcSafe for [T; 8] where
    T: GcSafe,
    T: Trace, 

const NEEDS_DROP: bool

impl<T> GcSafe for [T; 9] where
    T: GcSafe,
    T: Trace, 

const NEEDS_DROP: bool

impl<T> GcSafe for [T; 10] where
    T: GcSafe,
    T: Trace, 

const NEEDS_DROP: bool

impl<T> GcSafe for [T; 11] where
    T: GcSafe,
    T: Trace, 

const NEEDS_DROP: bool

impl<T> GcSafe for [T; 12] where
    T: GcSafe,
    T: Trace, 

const NEEDS_DROP: bool

impl<T> GcSafe for [T; 13] where
    T: GcSafe,
    T: Trace, 

const NEEDS_DROP: bool

impl<T> GcSafe for [T; 14] where
    T: GcSafe,
    T: Trace, 

const NEEDS_DROP: bool

impl<T> GcSafe for [T; 15] where
    T: GcSafe,
    T: Trace, 

const NEEDS_DROP: bool

impl<T> GcSafe for [T; 16] where
    T: GcSafe,
    T: Trace, 

const NEEDS_DROP: bool

impl<T> GcSafe for [T; 17] where
    T: GcSafe,
    T: Trace, 

const NEEDS_DROP: bool

impl<T> GcSafe for [T; 18] where
    T: GcSafe,
    T: Trace, 

const NEEDS_DROP: bool

impl<T> GcSafe for [T; 19] where
    T: GcSafe,
    T: Trace, 

const NEEDS_DROP: bool

impl<T> GcSafe for [T; 20] where
    T: GcSafe,
    T: Trace, 

const NEEDS_DROP: bool

impl<T> GcSafe for [T; 24] where
    T: GcSafe,
    T: Trace, 

const NEEDS_DROP: bool

impl<T> GcSafe for [T; 32] where
    T: GcSafe,
    T: Trace, 

const NEEDS_DROP: bool

impl<T> GcSafe for [T; 48] where
    T: GcSafe,
    T: Trace, 

const NEEDS_DROP: bool

impl<T> GcSafe for [T; 64] where
    T: GcSafe,
    T: Trace, 

const NEEDS_DROP: bool

impl<T> GcSafe for [T; 100] where
    T: GcSafe,
    T: Trace, 

const NEEDS_DROP: bool

impl<T> GcSafe for [T; 128] where
    T: GcSafe,
    T: Trace, 

const NEEDS_DROP: bool

impl<T> GcSafe for [T; 256] where
    T: GcSafe,
    T: Trace, 

const NEEDS_DROP: bool

impl<T> GcSafe for [T; 512] where
    T: GcSafe,
    T: Trace, 

const NEEDS_DROP: bool

impl<T> GcSafe for [T; 1024] where
    T: GcSafe,
    T: Trace, 

const NEEDS_DROP: bool

impl<T> GcSafe for [T; 2048] where
    T: GcSafe,
    T: Trace, 

const NEEDS_DROP: bool

impl<T> GcSafe for [T; 4096] where
    T: GcSafe,
    T: Trace, 

const NEEDS_DROP: bool

impl<'a, T: 'a> GcSafe for &'a T where
    T: GcSafe,
    T: TraceImmutable, 

const NEEDS_DROP: bool

impl<'a, T: 'a> GcSafe for &'a mut T where
    T: GcSafe,
    T: Trace, 

const NEEDS_DROP: bool

impl<T> GcSafe for [T] where
    T: GcSafe,
    T: Trace, 

const NEEDS_DROP: bool

impl<T> GcSafe for Option<T> where
    T: GcSafe,
    T: Trace, 

const NEEDS_DROP: bool

impl<T> GcSafe for Wrapping<T> where
    T: GcSafe,
    T: Trace, 

const NEEDS_DROP: bool

impl<T> GcSafe for Vec<T> where
    T: GcSafe,
    T: Trace, 

const NEEDS_DROP: bool

impl<T> GcSafe for Box<T> where
    T: GcSafe,
    T: Trace, 

const NEEDS_DROP: bool

impl<T: TraceImmutable> GcSafe for Rc<T> where
    T: GcSafe,
    T: Trace, 

const NEEDS_DROP: bool

impl<T: TraceImmutable> GcSafe for Arc<T> where
    T: GcSafe,
    T: Trace, 

const NEEDS_DROP: bool

impl GcSafe for String

const NEEDS_DROP: bool

impl<K: TraceImmutable, V> GcSafe for HashMap<K, V> where
    K: GcSafe,
    V: GcSafe,
    K: Trace,
    V: Trace, 

const NEEDS_DROP: bool

impl<T: TraceImmutable> GcSafe for HashSet<T> where
    T: GcSafe,
    T: Trace, 

const NEEDS_DROP: bool

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Implementors

impl<'gc, T: GcSafe + 'gc, Id: CollectorId> GcSafe for Gc<'gc, T, Id>

Double-indirection is completely safe

const NEEDS_DROP: bool

impl<T> GcSafe for AssumeNotTraced<T>

const NEEDS_DROP: bool

impl<T: GcSafe + Copy> GcSafe for GcCell<T>

const NEEDS_DROP: bool

Since T is Copy, we shouldn’t need to be dropped

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