Trait FromSlot 

pub trait FromSlot: Sized {
    const NATIVE_KIND: NativeKind;

    // Required method
    fn from_slot(bits: u64) -> Self;
}

Read a typed value from an 8-byte raw-bits slot.

The associated constant Self::NATIVE_KIND declares which kind the slot must have. The marshal-layer dispatcher guarantees the contract by reading arg_kinds() at registration and only invoking the body with matching slot bits — from_slot impls therefore do not invoke the deleted tag_bits dispatch.

Required Associated Constants

const NATIVE_KIND: NativeKind

Required Methods

fn from_slot(bits: u64) -> Self

SAFETY contract (enforced by the marshal-layer wrapper, not by this trait method): bits must have been produced by a slot that was statically proven to have kind NATIVE_KIND.

Dyn Compatibility

This trait is not dyn compatible.

In older versions of Rust, dyn compatibility was called "object safety".

Implementations on Foreign Types

impl FromSlot for Option<f64>

const NATIVE_KIND: NativeKind = NativeKind::NullableFloat64

fn from_slot(bits: u64) -> Self

impl FromSlot for bool

const NATIVE_KIND: NativeKind = NativeKind::Bool

fn from_slot(bits: u64) -> Self

impl FromSlot for f64

const NATIVE_KIND: NativeKind = NativeKind::Float64

fn from_slot(bits: u64) -> Self

impl FromSlot for i64

const NATIVE_KIND: NativeKind = NativeKind::Int64

fn from_slot(bits: u64) -> Self

impl FromSlot for Arc<String>

Read an Arc<String> from a heap-pointer slot.

The slot owns one strong reference; cloning it for the body’s use requires incrementing the refcount. The marshal wrapper does not take ownership of the slot — it stays valid for the duration of the call. The body receives an independent strong reference.

const NATIVE_KIND: NativeKind = NativeKind::String

fn from_slot(bits: u64) -> Self

impl FromSlot for Arc<Vec<f64>>

Read an Arc<Vec<f64>> from a NativeKind::Ptr(HeapKind::TypedArray) slot whose payload is *mut TypedArray<f64>. V3-S5 ckpt-5-prime²c Migration shape (a) — replaces the pre-migration FromSlot for Arc<AlignedTypedBuffer> entry.

const NATIVE_KIND: NativeKind

fn from_slot(bits: u64) -> Self

impl FromSlot for Arc<Vec<i64>>

Read an Arc<Vec<i64>> from a NativeKind::Ptr(HeapKind::TypedArray) slot whose payload is *mut TypedArray<i64>. V3-S5 ckpt-5-prime²c Migration shape (a) — replaces the pre-migration FromSlot for Arc<TypedBuffer<i64>> entry.

const NATIVE_KIND: NativeKind

fn from_slot(bits: u64) -> Self

impl FromSlot for Arc<Vec<u8>>

Read an Arc<Vec<u8>> from a NativeKind::Ptr(HeapKind::TypedArray) slot whose payload is *mut TypedArray<u8>. V3-S5 ckpt-5-prime²c Migration shape (a) — replaces the pre-migration FromSlot for Arc<TypedBuffer<u8>> entry.

Note: the pre-migration Bool-vs-U8 Rust-type-collision residual carries forward — Array<bool> lowers to *mut TypedArray<u8> per the v2 carrier shape (bool is stored as u8 with the dispatch-level Bool stamp at stamp_elem_type). A body declaring Arc<Vec<u8>> and being handed an Array<bool> slot will read raw bytes correctly but cannot distinguish “Array” from “Array” at this boundary. Resolution when a Bool consumer surfaces.

const NATIVE_KIND: NativeKind

fn from_slot(bits: u64) -> Self

impl FromSlot for Arc<DataTable>

where Self: Sized,

Read the inner Arc<DataTable> from a NativeKind::Ptr(HeapKind::DataTable) slot.

const NATIVE_KIND: NativeKind

fn from_slot(bits: u64) -> Self

impl FromSlot for Arc<IoHandleData>

where Self: Sized,

Read the inner Arc<IoHandleData> from a NativeKind::Ptr(HeapKind::IoHandle) slot.

const NATIVE_KIND: NativeKind

fn from_slot(bits: u64) -> Self

impl FromSlot for Vec<(Arc<String>, Arc<HeapValue>)>

Read a Vec<(Arc<String>, Arc<HeapValue>)> from a NativeKind::Ptr(HeapKind::HashMap) slot.

Body-type pattern: bodies declaring args: Vec<(Arc<String>, Arc<HeapValue>)> receive an owned pair-list with insertion order preserved and polymorphic-typed values. Each element is an opaque Arc<HeapValue>; the body is responsible for pattern-matching the inner kind per the option ε contract. No element-kind constraint at the marshal boundary.

const NATIVE_KIND: NativeKind

fn from_slot(bits: u64) -> Self

impl FromSlot for Vec<(Arc<String>, Arc<String>)>

Read a Vec<(Arc<String>, Arc<String>)> from a NativeKind::Ptr(HeapKind::HashMap) slot.

Body-type pattern: bodies declaring args: Vec<(Arc<String>, Arc<String>)> receive an owned pair-list with insertion order preserved. Each value is expected to be HeapValue::String(_); mismatch panics as the spec-permitted consistency check (docs/runtime-v2-spec.md).

const NATIVE_KIND: NativeKind

fn from_slot(bits: u64) -> Self

impl FromSlot for Vec<i64>

Read a Vec<i64> from a NativeKind::Ptr(HeapKind::TypedArray) slot whose payload is *mut TypedArray<i64>. V3-S5 ckpt-5-prime²c (2026-05-15): rewritten for the v2-raw flat-struct carrier. Owns-clone semantics.

const NATIVE_KIND: NativeKind

fn from_slot(bits: u64) -> Self

impl FromSlot for Vec<u8>

Read a Vec<u8> from a NativeKind::Ptr(HeapKind::TypedArray) slot whose payload is *mut TypedArray<u8>.

V3-S5 ckpt-5-prime²c (2026-05-15): rewritten for the v2-raw flat-struct carrier. Slot bits are a raw *mut TypedArray<u8> pointer; element-data is copied into a fresh Vec<u8> (owns-clone semantics — body receives an owned vector independent of the slot’s refcount share).

const NATIVE_KIND: NativeKind

fn from_slot(bits: u64) -> Self

impl FromSlot for Vec<Arc<HeapValue>>

Read a Vec<Arc<HeapValue>> from a NativeKind::Ptr(HeapKind::TypedArray) slot.

V3-S5 ckpt-5-prime²c (2026-05-15) SURFACE-AND-STOP: the materialize_heap_arcs helper (deleted alongside this comment block) re-wrapped each strict-typed element into a HeapValue::* Arc by pattern-matching the deleted TypedArrayData enum. The new *mut TypedArray<T> flat-struct carrier needs a per-T dispatcher (one impl per element width: *const StringObj, *const DecimalObj, TypedObjectPtr, char, etc.) plus a parallel element-kind discriminator in the marshal layer to know which T the slot was constructed for. The element discriminator already exists at the VM level (stamp_elem_type at crates/shape-vm/src/executor/v2_handlers/array.rs) but isn’t yet exposed at the marshal-FromSlot boundary.

Adding this dispatcher is the Round 2 Vec<Arc<HeapValue>> rewire follow-up; pairs with the from_typed_array_<T> constructor wave at crates/shape-value/src/slot.rs:142 and the matching ckpt-6 JIT FFI String/Decimal build work. Until that lands, the marshal-FromSlot panics with a structured error pointing at the follow-up — any stdlib body declaring Vec<Arc<HeapValue>> and reaching this from_slot is currently dead at the marshal boundary (consistent with V3-S5 ckpt-5’s wholesale HeapValue::TypedArray outer-arm deletion).

const NATIVE_KIND: NativeKind

fn from_slot(_bits: u64) -> Self

impl FromSlot for Vec<Arc<String>>

Read a Vec<Arc<String>> from a NativeKind::Ptr(HeapKind::TypedArray) slot whose payload is *mut TypedArray<*const StringObj>. V3-S5 ckpt-5-prime²c (2026-05-15): rewritten for the v2-raw flat-struct carrier (each element is a raw *const StringObj — the per-element allocator-managed v2 string carrier per crates/shape-value/src/v2/ string_obj.rs). Each element string is copied into a fresh Arc<String> (owns-clone semantics — body receives an owned vector of independent Arcs).

const NATIVE_KIND: NativeKind

fn from_slot(bits: u64) -> Self

Implementors