Lib does not get copied to result

[Qubasa]

The generated rust library does not get copied to result/lib even though copyLibs is set to true
The lib.rs file used

{

  inputs = {
    naersk.url = "github:nmattia/naersk/master";
    nixpkgs.url = "github:NixOS/nixpkgs/nixpkgs-unstable";
    utils.url = "github:numtide/flake-utils";

    mozillapkgs = {
      url = "github:mozilla/nixpkgs-mozilla";
      flake = false;
    };
  };

  outputs = { self, nixpkgs, utils, naersk, mozillapkgs }:
    utils.lib.eachDefaultSystem (system:
      let
        pkgs = import nixpkgs { inherit system; };
        # Get a specific rust version
        mozilla = pkgs.callPackage (mozillapkgs + "/package-set.nix") { };
        rust = (mozilla.rustChannelOf {
          date = "2021-10-26"; # get the current date with `date -I`
          channel = "nightly";
          sha256 = "sha256-1hLbypXA+nuH7o3AHCokzSBZAvQxvef4x9+XxO3aBao==";
        }).rust;
        # Override the version used in naersk
        naersk-lib = naersk.lib."${system}".override {
          cargo = rust;
          rustc = rust;
        };
      in
      {

        defaultPackage = naersk-lib.buildPackage {
          src = ./.;
          copyLibs = true;
        };

        defaultApp = utils.lib.mkApp {
          drv = self.defaultPackage."${system}";
        };

        devShell = with pkgs; mkShell {
          buildInputs = [ cargo rustc rustfmt pre-commit rustPackages.clippy ];
          RUST_SRC_PATH = rustPlatform.rustLibSrc;
        };

      });

}