basic devshell with clang: error: The option 'language.c.__ignoreNulls' does not exist

[ppenguin]

Describe the bug

When building a (pretty basic) devshell that has language.c = pkgs.clang (or similar) defined,
I get an error: The option 'language.c.__ignoreNulls' does not exist

To Reproduce

Steps to reproduce the behavior:

1. Make the following devshell definition in the flake.nix instantiated from the devshell template:

        pkgs.devshell.mkShell {
          # imports = [ (pkgs.devshell.importTOML ./devshell.toml) ];
          imports = [ "${devshell}/extra/language/c.nix" ];
          name = "flutter";
          language.c = pkgs.llvmPackages_15.clangUseLLVM;
          packages = [ pkgs.flutter ];
        };
   

2. Observe the error:

      direnv: loading ~/devel/playgnd/flutter/devshelltst/.envrc                                         
      direnv: using flake --show-trace
      error: The option `language.c.__ignoreNulls' does not exist. Definition values:
         - In `<unknown-file>': true
   

Expected behavior

To get a flutter devshell with a clang c++ env.

System information

nixos amd64

Additional context