anchor.diff:  
   in
   stdenv.mkDerivation {
  -  name = "swift-${version}";
  +  name = "swift-${versions.swift}";
   
     nativeBuildInputs = [
       autoconf
  
positive.code: }:
  
  let
    version = "5.4.2";
  
    # These dependency versions can be found in utils/update_checkout/update-checkout-config.json.
    swiftArgumentParserVersion = "0.3.0";
    yamsVersion = "3.0.1";
    swiftFormatVersion = "0.50400.0";
  
    fetchSwiftRelease = { repo, sha256, fetchSubmodules ? false }:
      fetchFromGitHub {
        owner = "apple";
        inherit repo sha256 fetchSubmodules;
        rev = "swift-${version}-RELEASE";
        name = "${repo}-${version}-src";
      };
  
    # Sources based on utils/update_checkout/update_checkout-config.json.
    sources = {
      swift = fetchSwiftRelease {
        repo = "swift";
        sha256 = "0qrkqkwpmk312fi12kwwyihin01qb7sphhdz5c6an8j1rjfd9wbv";
      };
      cmark = fetchSwiftRelease {
        repo = "swift-cmark";
  
negative.code:     cp -r ${sources.toolsSupportCore} swift-tools-support-core
      cp -r ${sources.swiftpm} swiftpm
      cp -r ${sources.syntax} swift-syntax
      cp -r ${sources.corelibsXctest} swift-corelibs-xctest
      cp -r ${sources.corelibsFoundation} swift-corelibs-foundation
      cp -r ${sources.corelibsLibdispatch} swift-corelibs-libdispatch
      cp -r ${sources.yams} yams
      cp -r ${sources.indexstoreDb} indexstore-db
      cp -r ${sources.sourcekitLsp} sourcekit-lsp
      cp -r ${sources.format} swift-format
      cp -r ${sources.crypto} swift-crypto
      cp -r ${sources.llvmProject} llvm-project
  
      chmod -R u+w .
  