forEach on same path as repeat fails with "No such struct field" error

[johngrimes]

ViewDefinitions that use forEach to access the same path being recursively traversed by repeat fail with a Spark AnalysisException.

Reproduction

{
  "resourceType": "ViewDefinition",
  "resource": "CodeSystem",
  "status": "active",
  "select": [
    {
      "column": [{"name": "cs_id", "path": "id"}]
    },
    {
      "repeat": ["concept"],
      "column": [{"name": "parent_code", "path": "code"}],
      "select": [
        {
          "forEach": "concept",
          "column": [{"name": "code", "path": "code"}]
        }
      ]
    }
  ]
}

Expected behaviour

The view should produce rows showing parent-child relationships in the CodeSystem concept hierarchy, with parent_code containing the code of each concept and code containing the codes of its direct children.

Actual behaviour

Returns HTTP 500 with:

[FIELD_NOT_FOUND] No such struct field `concept` in `id`, `code`, `display`, `definition`, `designation`, `property`, `_fid`. SQLSTATE: 42704