Trait impl detection fails when using associated types aliased to eachother

[Osspial]

When attempting to compile the following code, the compiler mistakenly rejects it, complaining that the Point type returned by max doesn't implement Sub<Self::D::Vector>. However, Point does implement the trait - it's just that EuclideanSpace::Diff is being aliased through Dimensionality::Vector.

Playground link

use std::ops::*;

pub trait Geometry {
    type D: Dimensionality;

    fn min(&self) -> <Self::D as Dimensionality>::Point {
        self.max() - self.dims()
    }

    fn max(&self) -> <Self::D as Dimensionality>::Point;
    
    fn dims(&self) -> <Self::D as Dimensionality>::Vector;
}

pub trait Dimensionality {
    type Point: EuclideanSpace<Diff=Self::Vector>;
    type Vector;
}

pub trait EuclideanSpace:
    Copy + Clone +
    Add<<Self as EuclideanSpace>::Diff, Output = Self> +
    Sub<<Self as EuclideanSpace>::Diff, Output = Self>
{
    type Diff;
}

Redefining fn dims as follows so that it directly returns the requested type also fails to compile, with the same error:

Playground link

fn dims(&self) -> <<Self::D as Dimensionality>::Point as EuclideanSpace>::Diff;

It seems the only way to make that code compile is to redefine Dimensionality as follows, removing the alias between EuclideanSpace::Diff and Dimensionality::Vector:

Playground link

pub trait Dimensionality {
    type Point: EuclideanSpace;
    type Vector;
}

This is happening on all versions of the compiler I've tested, one of those being stable 1.29.0.

[rkarp]

This is another duplicate of #24159, which I know all too well by now. Here's how to fix your first example:

Playground Link

[jonas-schievink]

Closing as a duplicate of #24159