Need help understanding which type constraints to use for num_enum

Hello,
I am fairly new to Rust and I am trying to convert a snippet of Rust code into a version that's up to date with the current crate version, as well as change it slightly to operate on the self instead of defining a new free function

Here's a link to the code

#[derive(Debug, Copy, Clone, FromPrimitive)]
enum Direction {
    NORTH = 0,
    SOUTH,
    EAST,
    WEST,
}

fn turn(d: Direction) -> Direction {
    match FromPrimitive::from_u8(d as u8 + 1) {
        Some(d2) => d2,
        None => FromPrimitive::from_u8(0).unwrap(),
    }
}

I figured out how to update the exact function with crate num_enum version 0.7.3

use num_enum::{FromPrimitive, TryFromPrimitive};

//#[derive(Debug, Copy, Clone, FromPrimitive)]
#[derive(Debug, Default, Copy, Clone, TryFromPrimitive)]
#[repr(u8)]
enum Direction {
    #[default]
    NORTH = 0,
    SOUTH,
    EAST,
    WEST,
}

fn turn(d: Direction) -> Direction {
    match TryFromPrimitive::try_from_primitive(d as u8 + 1) {
        Ok(res) => res,
        Err(_) => Direction::default(),
    }
}

But I'm having some trouble with defining it on the self instead. Here's what I've tried so far:

//impl<T> Direction where T: From<Direction> + Add<u8> {
impl<T: Add<u8>> Direction where T: From<Direction>  {
    fn next(self) -> Self {
        //let test = <Direction as Into<T>>::into(self) + 1u8;
        let test = <Direction as Into<T>>::into(self);
        //let test = self.into() + 1u8;
        self
    }
}

I added the T type param when rustc suggested let test = <Direction as Into<T>>::into(self); when I tried to do let test = self.into() + 1u8;. Of course, I don't expect rustc to give a suggestion for each step. Specifically, I'm confused about the error: the type parameter T is not constrained by the impl trait, self type, or predicates as I thought that the Add<u8> on that line would constrain it.

Source: View source