shell.nix exetubables don't seem to be made available after selecting shell.nix

[bbarker]

I'd like to be able to use the Dhall LSP Server extension with dependencies made available via a shell.nix file.

To Reproduce I created a shell.nix file with the contents:

{ pkgs ? import <nixpkgs> {} }:
  pkgs.mkShell {
    # nativeBuildInputs is usually what you want -- tools you need to run
    nativeBuildInputs = [ pkgs.dhall-lsp-server ];
}

However, after selecting the Nix environment and reloading VS Code, I still get this error:

No `dhall-lsp-server` executable is available in the VSCode PATH.
You might need to install [Dhall LSP server](https://github.com/PanAeon/dhall-lsp-server).
Also you might want to set an absolute path to the `dhall-lsp-server` executable in the plugin settings.

In the vs code terminal, I can confirm the dhall-lsp-server executable is available after running nix-shell shell.nix.

Expected behavior I would expect VS Code to be able to find the dhall-lsp-server executable.

Environment:

• OS:

   Linux beb82dell0 5.4.0-90-generic #101-Ubuntu SMP Fri Oct 15 20:00:55 UTC 2021 x86_64 x86_64 x86_64 GNU/Linux
  $ lsb_release -a
  No LSB modules are available.
  Distributor ID: Ubuntu
  Description:    Ubuntu 20.04.3 LTS
  Release:    20.04
  Codename:   focal

• VS Code

  Version: 1.54.3
  Commit: 2b9aebd5354a3629c3aba0a5f5df49f43d6689f8
  Date: 2021-03-15T10:55:24.277Z
  Electron: 11.3.0
  Chrome: 87.0.4280.141
  Node.js: 12.18.3
  V8: 8.7.220.31-electron.0
  OS: Linux x64 5.4.0-90-generic

[bbarker]

It looks like I also needed dhall from Nix: nativeBuildInputs = [ pkgs.dhall pkgs.dhall-lsp-server ];