{"ast_node_type":"other","tokens":[{"end":46,"kind":"keyword","start":0,"text":"///"}]}
/// - Input: `[a, x, b, y]`. Output: `[a, x]`.
/// - Input: `[b, a, x]`. Output: `[b, a, x]`.
fn pare_down(candidates: &mut Vec<usize>, closure: &BitMatrix<usize, usize>) {