Question about const generics

[chipsenkbeil]

I've seen some examples of using serde_as for explicitly-defined size ranges, but I'm struggling to figure out how to apply to const generics, if it's even possible.

use serde::{Serialize, Deserialize};
use serde_with::serde_as;

#[serde_as]
#[derive(Copy, Clone, PartialEq, Eq, Serialize, Deserialize)]
struct FixedMatrix<T, const ROW: usize, const COL: usize> {
    serde_as(as = "[[_; ROW]; COL]")
    data: [[T; ROW]; COL],
}

Was browsing through serde-rs/serde#1937 and saw mention of:

#[serde_with::serde_as]
#[derive(Serialize)]
struct Foo {
    #[serde_as(as = "[_; 2]")]
    bar: [String; 2],
    #[serde_as(as = "Vec<[_; 5]>")]
    foobar: Vec<[u8; 5]>,
}