error:
       … while calling the 'derivationStrict' builtin
         at «nix-internal»/derivation-internal.nix:37:12:
           36|
           37|   strict = derivationStrict drvAttrs;
             |            ^
           38|

       … while evaluating derivation 'nixos-system-tomservo-26.11.20260907.9485e5e'
         whose name attribute is located at «github:nixos/nixpkgs/9485e5e151b6bcea0fef6980325ec8fb4194d30c?narHash=sha256-mu5sizob4fS6ECwiwFMIlLRn5OZt/DlY29E1xK7ArZc%3D»/pkgs/stdenv/generic/make-derivation.nix:651:11

       … while evaluating attribute 'buildCommand' of derivation 'nixos-system-tomservo-26.11.20260907.9485e5e'
         at «github:nixos/nixpkgs/9485e5e151b6bcea0fef6980325ec8fb4194d30c?narHash=sha256-mu5sizob4fS6ECwiwFMIlLRn5OZt/DlY29E1xK7ArZc%3D»/nixos/modules/system/activation/top-level.nix:63:7:
           62|       allowSubstitutes = false;
           63|       buildCommand = systemBuilder;
             |       ^
           64|

       … while evaluating the option `environment.etc."systemd/user".source':

       … while evaluating the option `systemd.user.units."sunshine.service".text':

       … while evaluating definitions from `/nix/store/f5gvqd289a6mx4r0qcwp8ch0fw7xivc1-source/nixos/modules/system/boot/systemd/user.nix':

       … while evaluating the option `systemd.user.services.sunshine.serviceConfig':

       … while evaluating definitions from `/nix/store/f5gvqd289a6mx4r0qcwp8ch0fw7xivc1-source/nixos/modules/services/networking/sunshine.nix':

       … while evaluating the option `services.sunshine.settings':

       … while evaluating definitions from `/nix/store/46dpbiczarz0bkd2d7lcng7mjr6w97vr-source/hosts/tomservo/sunshine.nix':

       (stack trace truncated; use '--show-trace' to show the full, detailed trace)

       error: cannot convert a function to JSON
       at «github:nixos/nixpkgs/9485e5e151b6bcea0fef6980325ec8fb4194d30c?narHash=sha256-mu5sizob4fS6ECwiwFMIlLRn5OZt/DlY29E1xK7ArZc%3D»/lib/lists.nix:59:15:
           58|   */
           59|   singleton = x: [ x ];
             |               ^
           60|