anchor.diff:    cxxForHost="${stdenv.cc}/bin/${stdenv.cc.targetPrefix}c++";
     releaseDir = "target/${rustTarget}/${buildType}";
   
  +  # Specify the stdenv's `diff` by abspath to ensure that the user's build
  +  # inputs do not cause us to find the wrong `diff`.
  +  diff = "${diffutils}/bin/diff";
  +
   in
   
   stdenv.mkDerivation (args // {
  
positive.code:     srcLockfile=$NIX_BUILD_TOP/$sourceRoot/Cargo.lock
  
      echo "Validating consistency between $srcLockfile and $cargoDepsLockfile"
      if ! diff $srcLockfile $cargoDepsLockfile; then
  
        # If the diff failed, first double-check that the file exists, so we can
        # give a friendlier error msg.
  
negative.code: { stdenv
  , buildPackages
  , cacert
  , cargo
  , diffutils
  , fetchCargoTarball
  , git
  , rust
  , rustc
  , windows
  }:
  
  { name ? "${args.pname}-${args.version}"
  , cargoSha256 ? "unset"
  