In reply to @theo-paris:matrix.org

Not sure if this is the right place for this but:
I was testing github.com/NixOS/nixpkgs/pull/463361 with a nixos config flake using

  nixpkgs.localSystem = {
    system = "x86_64-linux";
    useLLVM = true;
    linker = "lld";
  };

And I ran into the following error:

       … while evaluating the option `home-manager.users.theo.i18n.glibcLocales':

       … while evaluating the option `i18n.glibcLocales':

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

       error: function 'anonymous lambda' called with unexpected argument 'nativeBuildInputs'
       at /nix/store/hq30166l4qc2l2va8v4lj9fyg894wdqs-source/pkgs/build-support/fetchurl/boot.nix:10:1:
            9|
           10| {
             | ^
           11|   url ? builtins.head urls,

That's a common symptom of bootstrap issues
The bootstrap fetchurl is used in a place where the full fetchurl should be used.
It's not an issue in fetchurl itself

https://github.com/NixOS/nixpkgs/blob/master/pkgs/build-support/fetchurl/boot.nix