{ ... }: let /* Returns true if it is being evaluated using restrict-eval, false if not. It's more robust than using `builtins.getEnv` since it isn't fooled by `env -i`. See https://github.com/NixOS/nix/issues/6579 for a description of the behavior. Precise cause in the evaluator / store implementation is unclear. Type: bool */ inRestrictedEval = builtins.pathExists (toString ./guinea-pig + "/."); in { inherit inRestrictedEval; }