{
  "id": "C021",
  "synthetic": true,
  "checked_at": "2026-10-24",
  "input": {
    "variables": {
      "DEMO": "fixture",
      "EMPTY": ""
    },
    "expressions": [
      "demo$DEMO",
      "demo$$DEMO",
      "${MISSING:?must-set}",
      "${EMPTY:?must-set}",
      "${DEMO:?must-set}"
    ],
    "expected": [
      "demofixture",
      "demo$DEMO",
      "required-error",
      "required-error",
      "fixture"
    ],
    "actual_compose": false
  }
}