syntax_data: {"ast_node_type":"other","tokens":[{"end":54,"kind":"keyword","start":0,"text":"///"}]}
source_snippet:     /// `trait_def_id` MUST BE the `DefId` of a trait.
context_before:     ///
context_after:     pub fn all_impls(self, trait_def_id: DefId) -> impl Iterator<Item = DefId> {