Function count_to_i64 

pub(crate) fn count_to_i64(count: usize) -> i64

Converts a count of elements to i64.

Exact for every caller here: each counts the set days of a seven-element week mask, so the count is 0..=7.

Panics

Panics if the count exceeds i64::MAX, which no fixed-size mask can reach.