syntax_data: {"ast_node_type":"variable","tokens":[{"end":95,"kind":"keyword","start":0,"text":"let"}]}
source_snippet:                     let rpitit_def_id = tcx.associated_item(def_id).trait_item_def_id.unwrap();
context_before:                     let impl_def_id = tcx.local_parent(def_id);
context_after:                     let args = ty::GenericArgs::identity_for_item(tcx, def_id).rebase_onto(