LDC-E1305 — Required-field and lowering errors

What it means

This is an error family for missing required payload fields, invalid closed field values, and unsupported lowering combinations. The message identifies the declaration and field; the code alone does not mean “missing bearer”. Unsupported quantifier domains use E1321; unsupported match patterns use E0205. The example below demonstrates one member of this family.

A duty binds someone: the head must name the bearer who owes the performance, alongside the goal that counts as performing. A duty head with no bearer states an obligation nobody carries, so the compiler stops at the head and asks who owes it.

This code also rejects a revision operation whose kind is outside the closed §32.1 set: replace, insert, repeal, and renumber. Such an operation cannot be discarded while the command reports success. Other uses of this code include required-field and lowering diagnostics. Severity is always error; the engine message identifies the rejected field or operation.

The repair is one field: name the bearer, usually a variable the rule already binds. A duty with its bearer and its goal lowers 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 Tenant;
relation trig(t: Tenant) kind empirical;
relation done(t: Tenant) kind institutional;
rule R defeasible {
    for t: Tenant;
    when trig(t);
    then duty D {
        beneficiary t;
        achieve done(t) during [@2026-01-01, infinity);
    };
}

Fix

Arxo Law

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

entity Tenant;
relation trig(t: Tenant) kind empirical;
relation done(t: Tenant) kind institutional;
rule R defeasible {
    for t: Tenant;
    when trig(t);
    then duty D {
        bearer t;
        beneficiary t;
        achieve done(t) during [@2026-01-01, infinity);
    };
}

Engine message

The engine reports this in its own wording:

Output

example.law:11:10: error LDC-E1305: duty "D" without bearer (§123)

Related

For a §85 calendar declaration, this error also reports missing required snapshot fields: timezone, valid (authoring period), datasetHash (content_hash), timezoneDbSnapshot (timezone_db), or a missing source (sourceArtifacts must contain at least one item). Rejected field values do not count as present. Compilation refuses to emit the incomplete snapshot.

• Duties — what a duty head must carry.
• LDC-E1302 — what exceptions a norm head may carry.