this derivation will be built:
  /nix/store/rs327fghwky70idddplp1x21jb5w1s7f-treefmt-check.drv
building '/nix/store/rs327fghwky70idddplp1x21jb5w1s7f-treefmt-check.drv'
treefmt-check> tribuchet: building on jamie
treefmt-check> treefmt v2.5.0traversed 28 files
treefmt-check> emitted 17 files for processing
treefmt-check> formatted 17 files (1 changed) in 225ms
treefmt-check>  M src/instantiate.rs
treefmt-check> diff --git a/src/instantiate.rs b/src/instantiate.rs
treefmt-check> index dabd8f5..132fec4 100644
treefmt-check> --- a/src/instantiate.rs
treefmt-check> +++ b/src/instantiate.rs
treefmt-check> @@ -215,13 +215,22 @@ mod tests {
treefmt-check>      fn build_flake_expression_single_attr_has_resolution_logic() {
treefmt-check>          let expr = build_flake_expression("/nix/store/x", "sha256-abc", "samba");
treefmt-check>          // Must contain all three fallback branches.
treefmt-check> -        assert!(expr.contains("f ? samba"), "missing top-level check: {expr}");
treefmt-check> -        assert!(expr.contains("f ? packages"), "missing packages branch: {expr}");
treefmt-check> +        assert!(
treefmt-check> +            expr.contains("f ? samba"),
treefmt-check> +            "missing top-level check: {expr}"
treefmt-check> +        );
treefmt-check> +        assert!(
treefmt-check> +            expr.contains("f ? packages"),
treefmt-check> +            "missing packages branch: {expr}"
treefmt-check> +        );
treefmt-check>          assert!(
treefmt-check>              expr.contains("f ? legacyPackages"),
treefmt-check>              "missing legacyPackages branch: {expr}"
treefmt-check>          );
treefmt-check> -        assert!(expr.contains("builtins.currentSystem"), "missing system: {expr}");
treefmt-check> +        assert!(
treefmt-check> +            expr.contains("builtins.currentSystem"),
treefmt-check> +            "missing system: {expr}"
treefmt-check> +        );
treefmt-check>      }
treefmt-check>  
treefmt-check>      #[test]
treefmt-check> @@ -230,12 +239,25 @@ mod tests {
treefmt-check>          // must also go through resolution — the top-level `f ? <attr>` branch
treefmt-check>          // handles the already-qualified case without a separate code path.
treefmt-check>          let expr = build_flake_expression("/nix/store/x", "sha256-abc", "foo.unwrapped");
treefmt-check> -        assert!(expr.contains("f ? foo.unwrapped"), "missing top-level check: {expr}");
treefmt-check> -        assert!(expr.contains("f ? packages"), "missing packages branch: {expr}");
treefmt-check> -        assert!(expr.contains("f ? legacyPackages"), "missing legacyPackages branch: {expr}");
treefmt-check> +        assert!(
treefmt-check> +            expr.contains("f ? foo.unwrapped"),
treefmt-check> +            "missing top-level check: {expr}"
treefmt-check> +        );
treefmt-check> +        assert!(
treefmt-check> +            expr.contains("f ? packages"),
treefmt-check> +            "missing packages branch: {expr}"
treefmt-check> +        );
treefmt-check> +        assert!(
treefmt-check> +            expr.contains("f ? legacyPackages"),
treefmt-check> +            "missing legacyPackages branch: {expr}"
treefmt-check> +        );
treefmt-check>          // A fully-qualified path works the same way; f ? packages.x86_64-linux.samba
treefmt-check>          // will succeed in branch 1 so branches 2 and 3 are never reached.
treefmt-check> -        let expr2 = build_flake_expression("/nix/store/x", "sha256-abc", "packages.x86_64-linux.samba");
treefmt-check> -        assert!(expr2.contains("f ? packages.x86_64-linux.samba"), "missing top-level check: {expr2}");
treefmt-check> +        let expr2 =
treefmt-check> +            build_flake_expression("/nix/store/x", "sha256-abc", "packages.x86_64-linux.samba");
treefmt-check> +        assert!(
treefmt-check> +            expr2.contains("f ? packages.x86_64-linux.samba"),
treefmt-check> +            "missing top-level check: {expr2}"
treefmt-check> +        );
treefmt-check>      }
treefmt-check>  }
error: Cannot build '/nix/store/rs327fghwky70idddplp1x21jb5w1s7f-treefmt-check.drv'.
       Reason: builder failed with exit code 1.
       Output paths:
         /nix/store/kw5zr0ia4s67bc0s4ly2ycsxyb73ly3n-treefmt-check
       Last 25 log lines:
       > -        assert!(expr.contains("f ? legacyPackages"), "missing legacyPackages branch: {expr}");
       > +        assert!(
       > +            expr.contains("f ? foo.unwrapped"),
       > +            "missing top-level check: {expr}"
       > +        );
       > +        assert!(
       > +            expr.contains("f ? packages"),
       > +            "missing packages branch: {expr}"
       > +        );
       > +        assert!(
       > +            expr.contains("f ? legacyPackages"),
       > +            "missing legacyPackages branch: {expr}"
       > +        );
       >          // A fully-qualified path works the same way; f ? packages.x86_64-linux.samba
       >          // will succeed in branch 1 so branches 2 and 3 are never reached.
       > -        let expr2 = build_flake_expression("/nix/store/x", "sha256-abc", "packages.x86_64-linux.samba");
       > -        assert!(expr2.contains("f ? packages.x86_64-linux.samba"), "missing top-level check: {expr2}");
       > +        let expr2 =
       > +            build_flake_expression("/nix/store/x", "sha256-abc", "packages.x86_64-linux.samba");
       > +        assert!(
       > +            expr2.contains("f ? packages.x86_64-linux.samba"),
       > +            "missing top-level check: {expr2}"
       > +        );
       >      }
       >  }
       For full logs, run:
         nix log /nix/store/rs327fghwky70idddplp1x21jb5w1s7f-treefmt-check.drv