pkgs.lib.callPackageWith <Nixpkgs_subset> ( x: x ) {}
My intuition tells me that the <Nixpkgs_subset> that callPackageWith will be called with is based on the same Nixpkgs set imported at the top (i.e., pkgs). Is this correct?
I will eventually sit down with pen and paper to write out what happens exactly during the 2 calls (i.e., the import and the callPackage one), because I have all the pieces right now, but the endless recursive function calls and Nix laziness keeps throwing me off.