LDC-E1339 — Instance without a label

What it means

Every instance carries a human-readable label: generated norms descend from the instance, and readers must be able to tell whose they are. An instance with no label would emit anonymous norms, so the compiler stops at the instance and asks for the label.

The repair is one line: add the label. Labeled instances expand exactly as written.

Example

Arxo Law

language "law.core" version "0.2";
package demo.diagnostics version "0.1.0";
namespace "urn:law:demo:diagnostics";

entity Person;
entity Choice;
entity SpecialChoice : Choice;
entity Other;
const Selected: SpecialChoice = entity_ref("urn:choice:selected");
const Wrong: Other = entity_ref("urn:choice:wrong");
relation eligible(p: Person, choice: Choice) kind empirical;
relation applicable(p: Person, choice: Choice) kind institutional;
expansion fixed {
    params { subject: binder; choice: value; ground: relation(subject, choice); result: relation(subject, choice); }
    emit rule self/result defeasible {
        for subject;
        when ground(subject, choice);
        then result(subject, choice);
        scope from self; effective from self; labels from self; source from self;
    }
}
expand fixed Result {
    bind subject = person: Person;
    choice = Selected;
    ground = eligible;
    result = applicable;
    effective [@2026-01-01, @2027-01-01);
}

Fix

Arxo Law

language "law.core" version "0.2";
package demo.diagnostics version "0.1.0";
namespace "urn:law:demo:diagnostics";

entity Person;
entity Choice;
entity SpecialChoice : Choice;
entity Other;
const Selected: SpecialChoice = entity_ref("urn:choice:selected");
const Wrong: Other = entity_ref("urn:choice:wrong");
relation eligible(p: Person, choice: Choice) kind empirical;
relation applicable(p: Person, choice: Choice) kind institutional;
expansion fixed {
    params { subject: binder; choice: value; ground: relation(subject, choice); result: relation(subject, choice); }
    emit rule self/result defeasible {
        for subject;
        when ground(subject, choice);
        then result(subject, choice);
        scope from self; effective from self; labels from self; source from self;
    }
}
expand fixed Result {
    label en official "Fixed option";
    bind subject = person: Person;
    choice = Selected;
    ground = eligible;
    result = applicable;
    effective [@2026-01-01, @2027-01-01);
}

Engine message

The engine reports this in its own wording:

Output

example.law:22:14: error LDC-E1339: expand Result: the instance has no label

Related

• LDC-E1337 — the instance must honor the definition contract.
• LDC-E1338 — the instance name must be fresh.