{"ast_node_type":"other","tokens":[{"end":100,"kind":"keyword","start":0,"text":"//!"}]}
//! the algorithm can't distinguish them from a nonempty constructor. The only known case where this
//! reason is that if we specialize by them, nothing remains to witness the emptiness; the rest of
//! could happen is the `[..]` pattern on `[!; N]` with `N > 0` so we must take care to not emit it.