Struct CastFusionRule 

pub struct CastFusionRule { /* private fields */ }

Cast(src→dst) → Op(dst) ≡ Op(src) when the consumer has a kernel for src.

Only fires when the cast has exactly one consumer (MVP: avoids the DAG complication of partial fan-out elimination). Multi- consumer Cast handling is a follow-up: rewrite one consumer and keep the cast alive for the others.

Implementations

impl CastFusionRule

pub fn new(capabilities: CapabilityPredicate) -> Self

Build the rule with a capability predicate. The predicate closes over whatever capability source the caller has (a binding table, a route picker, a static manifest). The rule itself stays decoupled from those internals.

Trait Implementations

impl Rule for CastFusionRule

fn name(&self) -> &'static str

Stable, human-readable name. Shows up in panic messages and debug traces.

fn family(&self) -> RuleFamily

Which family this rule belongs to. Determines pass ordering.

fn matches(&self, graph: &Graph, id: NodeId) -> bool

Whether this rule can rewrite the node at id. Should be pure — same inputs, same answer. Called once per node per pass; the first matching rule wins.

fn rewrite( &self, graph: &mut Graph, id: NodeId, remap: &mut HashMap<NodeId, NodeId>, )

Apply the rewrite: append fresh nodes to the graph, declare any side-effect roots if the rewrite emits side-effecting ops, and write remap.insert(id, replacement_id) so the driver can redirect consumer edges. Calling this method implies matches returned true for the same (graph, id) — rewriters can rely on the structure the matcher checked for.