syntax_data: {"ast_node_type":"other","tokens":[{"end":87,"kind":"keyword","start":0,"text":"//"}]}
source_snippet:             // which doesn't redact this span (but that would mean passing in even more
context_before:             // from a foreign crate; we could also take into account `-Zmacro-backtrace`,
context_after:             // args to this function, lol).