Some cyclic unions incorrectly reduced

[ssalbdivad]

Discussed in #1197

^{Originally posted by agladysh November 12, 2024}
A somewhat silly reduced example:

import { ArkErrors, scope } from 'arktype';

const $ = scope({
  literal: '"foo"',
  record: {
    '[string]': 'value'
  },
  value: 'literal|literal[]|record',
}).export();

const result = $.value({ });

if (result instanceof ArkErrors) {
  // Error: must be an array (was object)
  throw new Error(result.summary);
}

console.log('passed');

All three types in value seem to be necessary to reproduce the issue.

What am I doing wrong?

[ssalbdivad]

This is definitely a bug, likely to do with the way the recursive references and reduced in the union.