{ nixpkgs }: let pkgs = import nixpkgs { system = "x86_64-linux"; overlays = [ ]; config = { problems.handlers.a.removal = "error"; }; }; in pkgs.stdenvNoCC.mkDerivation { pname = "a"; version = "0"; meta.problems = { removal.message = "This package has been abandoned upstream and will be removed."; }; }