Compiling graph v0.0.1 (file:///Users/benjyw/src/pants/src/rust/engine/graph)
error[E0658]: `impl Trait` in return position is experimental (see issue #34511)
   --> graph/src/lib.rs:437:8
    |
437 |   ) -> impl Iterator<Item = hashing::Digest> + 'g {
    |        ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^

error[E0658]: use of unstable library feature 'option_ref_mut_cloned' (see issue #43738)
   --> graph/src/lib.rs:180:61
    |
180 |       if let Some(mut entry) = self.pg.node_weight_mut(*id).cloned() {
    |                                                             ^^^^^^

error: aborting due to 2 previous errors

error: Could not compile `graph`.
warning: build failed, waiting for other jobs to finish...
error: build failed

Failed to build native engine.