syntax_data: {"ast_node_type":"other","tokens":[{"end":39,"kind":"keyword","start":0,"text":"///"}]}
source_snippet:     /// aka. `interner.parent(def_id)`.
context_before:     /// `TraitRef` containing this associated type, which is in `interner.associated_item(def_id).container`,
context_after:     pub def_id: I::DefId,