this derivation will be built:
  /nix/store/7qmjjdyzlp8mdf8yay5cfvm123cnprn8-iets-fmt-0.2.0.drv
error: build of '/nix/store/7qmjjdyzlp8mdf8yay5cfvm123cnprn8-iets-fmt-0.2.0.drv' on 'grpc://farm.numtide.com:50051?connect-timeout=21&system=aarch64-linux&token-file=/run/nix-farm-client/farm-token' failed: Cannot build '/nix/store/7qmjjdyzlp8mdf8yay5cfvm123cnprn8-iets-fmt-0.2.0.drv'.
       Reason: builder failed with exit code 1.
       Output paths:
         /nix/store/2pzjjq88sm76mbxs27z24wmmrqfby611-iets-fmt-0.2.0
       Last 25 log lines:
       > Running phase: configurePhase
       > default configurePhase, nothing to do
       > Running phase: buildPhase
       > +++ command cargo --version
       > cargo 1.99.0 (5f94df478 2026-08-27)
       > +++ command cargo fmt -- --check
       > Diff in /build/source/src/compile/mod.rs:73:
       >  /// Intermediate attrpath-merged binding tree, mirroring Nix's `addAttr`.
       >  /// Every variable reference is a `Var` or an `inherit` name.
       >  fn var_uses(ast: &Ast) -> FxHashMap<Sym, Vec<u32>> {
       > -    let vars = ast.exprs.iter().zip(&ast.spans).filter_map(|(e, s)| match e {
       > -        Expr::Var(v) => Some((*v, s)),
       > -        _ => None,
       > -    });
       > +    let vars = ast
       > +        .exprs
       > +        .iter()
       > +        .zip(&ast.spans)
       > +        .filter_map(|(e, s)| match e {
       > +            Expr::Var(v) => Some((*v, s)),
       > +            _ => None,
       > +        });
       >      let inherits = ast.names.iter().map(|(v, s)| (*v, s));
       >      let mut m: FxHashMap<Sym, Vec<u32>> = FxHashMap::default();
       >      for (v, s) in vars.chain(inherits) {
       For full logs, run:
         nix log /nix/store/7qmjjdyzlp8mdf8yay5cfvm123cnprn8-iets-fmt-0.2.0.drv
error: Cannot build '/nix/store/7qmjjdyzlp8mdf8yay5cfvm123cnprn8-iets-fmt-0.2.0.drv'.
       Reason: builder failed with exit code 1.
       Output paths:
         /nix/store/2pzjjq88sm76mbxs27z24wmmrqfby611-iets-fmt-0.2.0