{"ast_node_type":"other","tokens":[{"end":78,"kind":"keyword","start":0,"text":"///"}]}
    /// Invert a bijective mapping, i.e. `invert(map)[y] = x` if `map[x] = y`,
impl<I: Idx, J: Idx> IndexSlice<I, J> {
    /// assuming the values in `self` are a permutation of `0..self.len()`.