syntax_data: {"ast_node_type":"other","tokens":[{"end":28,"kind":"keyword","start":0,"text":"///"}]}
source_snippet:     /// must be implemented.
context_before:     /// List of functions from `#[rustc_must_implement_one_of]` attribute one of which
context_after:     pub must_implement_one_of: Option<Box<[Ident]>>,