{"ast_node_type":"other","tokens":[{"end":79,"kind":"keyword","start":0,"text":"///"}]}
/// operations are done via `TyCtxt`. A `TyCtxt` is obtained for a `GlobalCtxt`
/// `GlobalCtxt`, and in practice `TyCtxt` is passed around everywhere, and all
/// by calling `enter` with a closure `f`. That function creates both the