Enum WriteError 

pub enum WriteError {
    UnknownWire {
        key: String,
        known: Vec<String>,
    },
    TypeMismatch {
        slot: String,
        expected: PortType,
        got: PortType,
    },
    CoordinateSlot {
        slot: String,
    },
    ConstSlot {
        slot: String,
    },
    FromParent {
        slot: String,
        expected: PortType,
        got: PortType,
    },
}

Error returned by Kernel::set_input and Kernel::set_input_at when the typed-write contract at the composition-substrate boundary cannot be satisfied.

Per composition_substrate.md axiom S4, “T1 + T2 ensure writes are type-checked at the boundary” — the typed-write API rejects writes whose Value variant doesn’t match the declared slot port type. This error names the rejection reason.

Variants

UnknownWire

The wire key did not resolve to a known input slot. Carries the name that was looked up; for indexed writes the index is reported instead.

Fields

key: String

The name or index looked up.

known: Vec<String>

The kernel’s input slots, as Kernel::input_names reports them and in the same order, coordinates included. Empty only where the writer does not have the list.

Coordinates are in it although writing one by name is Self::CoordinateSlot rather than a success: a caller who mistyped a coordinate meant a name this kernel has, and is not helped by a list that leaves it out. The exact match is what the other variant is for. Every engine answers alike, and a host can check the list against input_names.

TypeMismatch

The value’s port type did not match the slot’s declared port type and no auto-adapter exists to heal the mismatch. Both expected and provided port types are reported for diagnostic clarity.

Fields

slot: String

The slot written.

expected: PortType

Its declared type.

got: PortType

The value’s type.

CoordinateSlot

The slot is a coordinate, which advances through set_inputs rather than being written by name or index. Writing one here would put the coordinate prefix out of step with the values a pull is about to read.

Fields

slot: String

The coordinate named.

ConstSlot

The slot holds a const binding’s value, which only Kernel::init writes. A const is fixed for the life of the kernel; to change it, write the inputs it reads and initialize.

Fields

slot: String

The const’s slot.

FromParent

A value a binder copied from the parent scope does not satisfy the type the child declares for the input of the same name. The parent’s output and the child’s input share the name.

Fields

slot: String

The child’s input, and the parent’s output it was copied from.

expected: PortType

The type the child declares.

got: PortType

The type of the parent’s value.

Trait Implementations

impl Clone for WriteError

fn clone(&self) -> Self

Returns a duplicate of the value.

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

Performs copy-assignment from source.

impl Debug for WriteError

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

Formats the value using the given formatter.

impl Display for WriteError

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

Formats the value using the given formatter.

impl Error for WriteError

fn source(&self) -> Option<&(dyn Error + 'static)>

Returns the lower-level source of this error, if any.

fn description(&self) -> &str

👎Deprecated since 1.42.0:

use the Display impl or to_string()

fn cause(&self) -> Option<&dyn Error>

👎Deprecated since 1.33.0:

replaced by Error::source, which can support downcasting

fn provide<'a>(&'a self, request: &mut Request<'a>)

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

Provides type-based access to context intended for error reports.

impl PartialEq for WriteError

fn eq(&self, other: &Self) -> bool

Equality operator ==.

fn ne(&self, other: &Rhs) -> bool

Inequality operator !=.

impl StructuralPartialEq for WriteError