roguelike-tutorial | Following along with The Complete Roguelike Tutorial | Genomics library

I'm making a toy roguelike and have a Level structure for storing the game map, for which the most naive implementation is a 2D vector.

I'm following this tutorial which uses a Vector of Vectors, but states that for performance gains it's also possible to use a single Vector of size MAP_HEIGHT * MAP_WIDTH, and to access a tile at (x, y) one can simply access map[y * MAP_WIDTH + x].

I'm trying to implement this faster method but using getters and setters is clunky, and public fields aren't that great either. I'd much prefer it to feel like a 2D vector.

In order to do that I need to implement the Index trait for my class, but I'm not sure how to get the result I want. Maybe by nesting the impls? I really no idea.

Here is my code with a terrible attempt at implementing Index for my structure, which obviously won't work for my purposes because it's one dimensional: