syntax_data: {"ast_node_type":"other","tokens":[{"end":36,"kind":"keyword","start":0,"text":"Coroutine(GenericArgsRef<'tcx>),"}]}
source_snippet:     Coroutine(GenericArgsRef<'tcx>),
context_before:     Closure(GenericArgsRef<'tcx>),
context_after:     CoroutineClosure(GenericArgsRef<'tcx>),