sema_playground.swift.response

[
  {
    key.kind: source.lang.swift.ref.var.global,
    key.offset: 25,
    key.length: 1
  }
]
[
  {
    key.line: 1,
    key.column: 5,
    key.filepath: sema_playground.swift,
    key.severity: source.diagnostic.severity.error,
    key.description: "cannot declare entity named '$blah'; the '$' prefix is reserved for implicitly-synthesized declarations",
    key.diagnostic_stage: source.diagnostic.stage.swift.sema
  }
]