Custom Nix Shell with specific Erlang and Elixir

elixir.nix

{ sources ? import ./sources.nix, pkgs ? import sources.nixpkgs { } }:

with pkgs;

let

  erlang = pkgs.erlang.override {
    version = "26.0-rc2";
    sha256 = "1xqzdqniv6af7cajd3agnqdi12n4fy644p8z07k7r24cp1lz7y03";
  };

  elixir = (beam.packagesWith erlang).elixir.override {
    version = "1.14.4";
    sha256 = "1dwvln654c85v498f1vymbwh38mij1w2kz3nwf9q5bab5ajk8plr";
  };

in buildEnv {
  name = "builder";
  paths = [
    erlang
    elixir
  ];
}

shell.nix

{ pkgs ? import <nixpkgs> { } }:

with pkgs;
let
  inherit (lib) optional optionals;
in mkShell {
  buildInputs = [ (import ./elixir.nix { inherit pkgs; }) ];
}

[nix-shell:~]$ elixir --version
Erlang/OTP 26 [RELEASE CANDIDATE 2] [erts-14.0] [source] [64-bit] [smp:16:16] [ds:16:16:10] [async-threads:1] [jit:ns]

Elixir 1.14.4 (compiled with Erlang/OTP 26)