syntax_data: {"ast_node_type":"other","tokens":[{"end":65,"kind":"keyword","start":0,"text":"///"}]}
source_snippet:     /// Used to generate new `AttrId`s. Every `AttrId` is unique.
context_before:     proc_macro_quoted_spans: AppendOnlyVec<Span>,
context_after:     pub attr_id_generator: AttrIdGenerator,