LDC-E2118 — A parameter on a type that takes none

For LLMs5 sections

What it means

Only a closed list of standard types takes parameters: option, result, list, set, map, interval, and money name their slots, and every other standard name stands alone. Writing a parameter on a name outside that list is rejected at the type — the parameter would otherwise travel into the lowered form unchecked by anything.

Dropping the parameter, or switching to the parametric type actually meant, fixes it. Parameters on the lawful seven keep working exactly as before.

Example

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

entity Mass;
relation weighed(m: Mass) kind empirical;
relation logged(q: Integer<Mass>) kind institutional;
rule R strict { for m: Mass; when weighed(m); then logged(3); }

Fix

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

entity Mass;
relation weighed(m: Mass) kind empirical;
relation logged(q: Integer) kind institutional;
rule R strict { for m: Mass; when weighed(m); then logged(3); }

Engine message

The engine reports this in its own wording:

example.law:7:20: error LDC-E2118: type `Integer` takes no parameter (§35, errata E-0194): the §35 table declares parametric only `Option<T>`, `Result<T, E>`, `List<T>`, `Set<T>`, `Map<K, V>`, `Interval<T>` and `Money<C>`; on other std names a parameter was lowered into CLIR and checked by nothing

Documentation for Arxo. Writings — blog.arxo.io.

Anonymous visit counts on stats.arxo.io, no cookies.