syntax_data: {"ast_node_type":"variable","tokens":[{"end":56,"kind":"keyword","start":0,"text":"let"}]}
source_snippet:                 let args = tcx.erase_regions(rcvr_args);
context_before:                 assert_eq!(name, sym::transmute);
context_after:                 Some(ty::Instance::new_raw(trait_item_id, args))