syntax_data: {"ast_node_type":"other","tokens":[{"end":81,"kind":"keyword","start":0,"text":"//"}]}
source_snippet:                                     // instead of simply using `field_def.ident`,
context_before:                                     // HACK(eddyb) this mimics `path_append`,
context_after:                                     // just to be able to handle disambiguators.