Struct Chain 

pub struct Chain { /* private fields */ }

The residual chain: every step of how you got there.

When a pipeline propagates through ?, each layer records what it computed. If a boundary is reached, the chain shows the full path — not just where you stopped, but every step on the way.

Implementations

impl Chain

pub fn new() -> Self

pub fn record(&mut self, label: &'static str, value: &dyn Debug)

Record a successful interior step.

pub fn record_boundary(&mut self, label: &'static str, value: &dyn Debug)

Record the residual at the boundary — the last step before propagation.

pub fn entries(&self) -> &[ChainEntry]

The entries in order, from first layer to the boundary.

pub fn depth(&self) -> usize

How many layers completed before the boundary.

Trait Implementations

impl Clone for Chain

fn clone(&self) -> Chain

Returns a duplicate of the value.

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

Performs copy-assignment from source.

impl Debug for Chain

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

Formats the value using the given formatter.

impl Default for Chain

fn default() -> Chain

Returns the “default value” for a type.

impl Display for Chain

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

Formats the value using the given formatter.