Import nix package without default.nix

Hi! I’m trying to import this package in my shell.nix

As you can see, it don’t have default.nix, but have release.nix, so I’m trying

let  proto3-suite-src = import (
        fetchTarball ""
     proto3-suite = pkgs'.callPackage (proto3-suite-src + "/release.nix") {};

But nix-shell still tries to evaluate default.nix for some reason:

opening file '/nix/store/8hja5xada0m86p4r5ljlhqvi49i7i27m-source/default.nix': No such file
 or directory

What’s wrong there and how to import packages like this?

This should work:

with import <nixpkgs> {};

  proto3-suite-src = fetchTarball "";
  proto3-suite = import (proto3-suite-src + "/release.nix") {};
in mkShell {
  buildInputs = [ proto3-suite.proto3-suite-linux ];

Thanks a lot! It worked!