Trait RTree::Point not implemented for a struct, though it is

help
1

RStar can create RTree index on any structure that implements RTreeObject.

Here's a piece of module, and it compiles correctly inside the crate where it sits:

use geo::{Point, LineString};
use rstar::{RTreeObject, AABB, RTree};
use serde::{Serialize, Deserialize};

#[derive(Serialize, Deserialize, Debug, Clone)]
pub struct LeapEdge {
	pub geom: LineString<f32>,
}

impl RTreeObject for LeapEdge {
	type Envelope = AABB<Point<f32>>;
	fn envelope(&self) -> Self::Envelope {
		self.geom.envelope()
	}
}

pub struct MyIndex {
    rtree: RTree<LeapEdge>
}

But when I try to import LeapEdge and declare RTree<LeapEdge> in another crate, it is imported correctly, but fails to compile:

use crate1::leap::LeapEdge;

pub struct MyIndex {
    rtree: RTree<LeapEdge>
}

Error:

    rtree: RTree<LeapEdge>
           ^^^^^^^^^^^^^^^ the trait `Point` is not implemented for `LeapEdge`

(trait Point is rstar::Point)

Importing all possible traits from rtstar didn't help.

What am I doing wrong?

2

The error message looks pretty clear to me, you are not implementing the trait Point. In the code you posted above I can only see an implementation of RTreeObject for LeadEdge, not Point.

3

When I tried adding that implementation in the crate #1, the error message was "conflicting implementations of trait Point".

So, now when I keep everything in crate 1 and have functions that instantiate objects there, everything works -- not just compiles, but creates an new RTree in crate 2.

error[E0119]: conflicting implementations of trait `RTreeObject` for type `LeapEdge`
  --> src/leap.rs:26:1
   |
26 | impl RTreeObject for LeapEdge {
   | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
   |
   = note: conflicting implementation in crate `rstar`:
           - impl<P> RTreeObject for P
             where P: rstar::Point;

I think it's blanket implementation.

4

: deleted former response/query - sorry, i quickly skimmed through and didn't notice you talk about published crates...

5

This is saying that RTreeObject is automatically implemented for any type that implements Point. So if you implemented Point you can't and don't need to implement RTreeObject for your type.

6

I found what was wrong: two crates had different versions of rstar and geo. One had geo=0.25 & rstar=0.10, another one had 0.25 & 0.11, and there's a bug with rstar updates being imcompatible with geo versions.

7

If anyone runs into this, here's the Github ticket.