syntax_data: {"ast_node_type":"other","tokens":[{"end":30,"kind":"keyword","start":0,"text":"if"}]}
source_snippet:                 if is_return {
context_before:             CoroutineKind::Desugared(CoroutineDesugaring::AsyncGen, _) => {
context_after:                     let ty::Adt(_poll_adt, args) = *self.old_yield_ty.kind() else { bug!() };