syntax_data: {"ast_node_type":"other","tokens":[{"end":55,"kind":"keyword","start":0,"text":"_use_existential_trait_ref_new_instead:"}]}
source_snippet:             _use_existential_trait_ref_new_instead: (),
context_before:             args: interner.mk_args(&trait_ref.args.as_slice()[1..]),
context_after:         }