syntax_data: {"ast_node_type":"other","tokens":[{"end":46,"kind":"keyword","start":0,"text":"//"}]}
source_snippet:                     // The signature should be
context_before:                 hir::CoroutineKind::Desugared(hir::CoroutineDesugaring::AsyncGen, _) => {
context_after:                     // `AsyncIterator::poll_next(_, &mut Context<'_>) -> Poll<Option<Output>>`