Just for completeness, there is one other major unstable feature that Alacritty requires. #![feature(step_trait)]. I forget the precise details, but I believe

Just for completeness, there is one other major unstable feature that Alacritty requires. #![feature(step_trait)]. I forget the precise details, but I believe this was required for using newtype wrappers as a `Range` for indexing. Specifically, the grid can be indexed as a range like grid[Line..Line]