Demonstrating missing buildInputs issue in Nixpkgs 20.03

BuildDependsIssue.hs

module Main where

main :: IO ()
main = putStrLn "Hello, Haskell!"

Makefile

19-09-buildDepends:
	nix eval -f shell.nix --json "drv-19-09.env.buildInputs"
	nix eval -f shell.nix --json "drv-19-09.env.nativeBuildInputs"

20-03-buildDepends:
	nix eval -f shell.nix --json "drv-20-03.env.buildInputs"
	nix eval -f shell.nix --json "drv-20-03.env.nativeBuildInputs"

19-09-buildTools:
	nix eval -f shell.nix --json "drvFix-19-09.env.buildInputs"
	nix eval -f shell.nix --json "drvFix-19-09.env.nativeBuildInputs"

20-03-buildTools:
	nix eval -f shell.nix --json "drvFix-20-03.env.buildInputs"
	nix eval -f shell.nix --json "drvFix-20-03.env.nativeBuildInputs"

minimal-env-issue.cabal

cabal-version:       >=1.10
-- Initial package description 'minimal-env-issue.cabal' generated by
-- 'cabal init'.  For further documentation, see
-- http://haskell.org/cabal/users-guide/

name:                minimal-env-issue
version:             0.1.0.0
-- synopsis:
-- description:
-- bug-reports:
-- license:
-- copyright:
-- category:
build-type:          Simple
extra-source-files:

executable minimal-env-issue
  main-is:             BuildDependsIssue.hs
  -- other-modules:
  -- other-extensions:
  build-depends:       base >=4.12 && <4.13
  -- hs-source-dirs:
  default-language:    Haskell2010

Setup.hs

import Distribution.Simple
main = defaultMain

shell.nix

{}:

let
  pkgs-19-09 = import (fetchGit (import ./version-working.nix)) { };

  pkgs-20-03 = import (fetchGit (import ./version-broken.nix)) { };

  drv = pkgs:
    pkgs.haskell.lib.addBuildDepends
      (pkgs.haskellPackages.callCabal2nix "minimal-env-issue" ./. {})
      (with pkgs.haskellPackages; [ ghcid ] ++ (with pkgs; [ minio ]));

  drvFix = pkgs:
    pkgs.haskell.lib.addBuildTools
      (pkgs.haskellPackages.callCabal2nix "minimal-env-issue" ./. {})
      (with pkgs.haskellPackages; [ ghcid ] ++ (with pkgs; [ minio ]));
in
rec {
  drv-19-09    = drv pkgs-19-09;
  drv-20-03    = drv pkgs-20-03;
  drvFix-19-09 = drvFix pkgs-19-09;
  drvFix-20-03 = drvFix pkgs-20-03;
}

version-broken.nix

{
  url = "git@github.com:/NixOS/nixpkgs";
  rev = "33c19df80d98ee48c8bb23e0736d8cc9be04ab31";
  ref = "release-20.03";
}

version-working.nix

{
  url = "git@github.com:/NixOS/nixpkgs";
  rev = "d011e4749457af484adf2e90062c83a44ad072a4";
  ref = "release-19.09";
}