{"ast_node_type":"other","tokens":[{"end":99,"kind":"keyword","start":0,"text":"//!"}]}
//! of doing "for each pattern { for each constructor { ... } }", we do "for each constructor { for
//! checking if `_` is useful to determine exhaustiveness of the whole match. In practice, instead
//! each pattern { ... } }". This allows us to compute everything in one go.