Enum TypeRelation 

pub enum TypeRelation {
    SameType(&'static [PortRef]),
    SameElementType(&'static [PortRef]),
    BroadcastShape {
        in0: PortRef,
        in1: PortRef,
        out: PortRef,
    },
    Elementwise {
        input: PortRef,
        output: PortRef,
    },
    ReduceOver {
        input: PortRef,
        output: PortRef,
    },
    Custom {
        name: &'static str,
        run: fn(&CustomRelationCtx<'_>) -> RelationResult,
    },
}

One type relation declared on an op. The TypeSolver instantiates each as a constraint node linked to its participating type variables via back-edges.

Variants

SameType(&'static [PortRef])

All listed ports share the SAME concrete TypeNode. Implements Julia’s “diagonal variable” rule - a port declared Tensor that participates in SameType([in0, in1, out0]) collapses to ONE element type across all three positions, regardless of the bound’s permissiveness.

SameElementType(&'static [PortRef])

All listed Tensor-typed ports share the same ELEMENT type. Shapes may differ (broadcasting is a separate concern). Add(x: Tensor, y: Tensor) -> Tensor uses this.

BroadcastShape

The output is the broadcast of two tensor inputs. Composes with SameElementType to express Add / Mul / Sub / Div fully.

Fields

in0: PortRef

First broadcast operand.

in1: PortRef

Second broadcast operand.

out: PortRef

Output (shape = broadcast(in0.shape, in1.shape)).

Elementwise

Output preserves the input’s TypeNode entirely. Used by element-wise unary ops (Sqrt, Neg, Abs, Relu, etc.): shape preserved, element type preserved.

Fields

input: PortRef

Input.

output: PortRef

Output.

ReduceOver

Output is a reduction over the input: same element type, reduced shape (driven by op attributes like axes). ReduceSum / ReduceMean / ReduceMax use this.

Fields

input: PortRef

Input tensor being reduced.

output: PortRef

Output tensor (lower rank or same rank with size-1 axes).

Custom

Escape hatch for ops that don’t fit a predicate. The custom function receives the current TypeNodes for participating ports and returns a RelationResult.

Use sparingly - Reshape, Gather, Concat, Cast, and any op with attribute-driven type changes need this.

Fields

name: &'static str

Stable identifier for diagnostics.

run: fn(&CustomRelationCtx<'_>) -> RelationResult

Solver entry point. Receives the participating ports’ current resolutions (Option<&TypeNode>); narrows them or returns Failed.

Trait Implementations

impl Debug for TypeRelation

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

Formats the value using the given formatter.