{"ast_node_type":"other","tokens":[{"end":100,"kind":"keyword","start":0,"text":"//!"}]}
//! first by inspecting the scrutinee syntactically (which gives us `cx.known_valid_scrutinee`), and
//! We track in the algorithm whether a given place is known to contain valid data. This is done
//! then by tracking validity of each column of the matrix (which correspond to places) as we