An attempt to use index on a type which doesn't implement the std::ops::Index
trait was performed.
Erroneous code example:
0u8[2]; // error: cannot index into a value of type `u8`
To be able to index into a type it needs to implement the std::ops::Index
trait. Example:
let v: Vec<u8> = vec![0, 1, 2, 3]; // The `Vec` type implements the `Index` trait so you can do: println!("{}", v[2]);