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