anchor.diff:  #
   # We need to keep around at least the latest version released with a stable
   # NixOS
  -
   let
     archs = {
  -    x86_64-linux  = "linux-x86_64";
  -    i686-linux    = "linux-i686";
  +    x86_64-linux = "linux-x86_64";
  +    i686-linux = "linux-i686";
       x86_64-darwin = "darwin-x86_64";
     };
   
  
positive.code:   checkInputs = [ git gmp openssl readline libxml2 libyaml ];
  
    genericBinary = { version, sha256s, rel ? 1 }:
    stdenv.mkDerivation rec {
      pname = "crystal-binary";
      inherit version;
  
      src = fetchurl {
        url = "https://github.com/crystal-lang/crystal/releases/download/${version}/crystal-${version}-${toString rel}-${arch}.tar.gz";
        sha256 = sha256s.${stdenv.system};
      };
  
      buildCommand = ''
        mkdir -p $out
        tar --strip-components=1 -C $out -xf ${src}
      '';
    };
  
    commonBuildInputs = extraBuildInputs: [
      boehmgc libatomic_ops pcre libevent libyaml zlib libxml2 openssl
    ] ++ extraBuildInputs
      ++ lib.optionals stdenv.isDarwin [ libiconv ];
  
    generic = (
      { version
      , sha256
      , binary
      , doCheck ? true
      , extraBuildInputs ? []
      , buildFlags ? ["all" "docs"]
      }:
        lib.fix (compiler: stdenv.mkDerivation {
          pname = "crystal";
          inherit buildFlags doCheck version;
  
          src = fetchFromGitHub {
            owner = "crystal-lang";
            repo  = "crystal";
            rev   = version;
            inherit sha256;
          };
  
          outputs = [ "out" "lib" "bin" ];
  
          postPatch = ''
            # Add dependency of crystal to docs to avoid issue on flag changes between releases
            # https://github.com/crystal-lang/crystal/pull/8792#issuecomment-614004782
            substituteInPlace Makefile \
              --replace 'docs: ## Generate standard library documentation' 'docs: crystal ## Generate standard library documentation'
  
            substituteInPlace src/crystal/system/unix/time.cr \
              --replace /usr/share/zoneinfo ${tzdata}/share/zoneinfo
  
            ln -sf spec/compiler spec/std
  
            # Dirty fix for when no sandboxing is enabled
            rm -rf /tmp/crystal
            mkdir -p /tmp/crystal
  
            substituteInPlace spec/std/file_spec.cr \
              --replace '/bin/ls' '${coreutils}/bin/ls' \
              --replace '/usr/share' '/tmp/crystal' \
              --replace '/usr' '/tmp'
  
            substituteInPlace spec/std/process_spec.cr \
              --replace '/bin/cat' '${coreutils}/bin/cat' \
              --replace '/bin/ls' '${coreutils}/bin/ls' \
              --replace '/usr/bin/env' '${coreutils}/bin/env' \
              --replace '"env"' '"${coreutils}/bin/env"' \
              --replace '"/usr"' '"/tmp"'
  
            substituteInPlace spec/std/socket/tcp_server_spec.cr \
              --replace '{% if flag?(:gnu) %}"listen: "{% else %}"bind: "{% end %}' '"bind: "'
  
            substituteInPlace spec/std/system_spec.cr \
              --replace '`hostname`' '`${hostname}/bin/hostname`'
  
            # See https://github.com/crystal-lang/crystal/pull/8640
            substituteInPlace spec/std/http/cookie_spec.cr \
              --replace '01 Jan 2020' '01 Jan #{Time.utc.year + 2}'
  
            # See https://github.com/crystal-lang/crystal/issues/8629
            substituteInPlace spec/std/socket/udp_socket_spec.cr \
              --replace 'it "joins and transmits to multicast groups"' 'pending "joins and transmits to multicast groups"'
  
            # See https://github.com/crystal-lang/crystal/pull/8699
            substituteInPlace spec/std/xml/xml_spec.cr \
              --replace 'it "handles errors"' 'pending "handles errors"'
          '';
  
          buildInputs = commonBuildInputs extraBuildInputs;
  
          nativeBuildInputs = [ binary makeWrapper which pkg-config llvmPackages.llvm ];
  
          makeFlags = [
            "CRYSTAL_CONFIG_VERSION=${version}"
          ];
  
          LLVM_CONFIG = "${llvmPackages.llvm}/bin/llvm-config";
  
          FLAGS = [
            "--release"
            "--single-module" # needed for deterministic builds
          ];
  
          # This makes sure we don't keep depending on the previous version of
          # crystal used to build this one.
          CRYSTAL_LIBRARY_PATH = "${placeholder "lib"}/crystal";
  
          # We *have* to add `which` to the PATH or crystal is unable to build
          # stuff later if which is not available.
          installPhase = ''
            runHook preInstall
  
            install -Dm755 .build/crystal $bin/bin/crystal
            wrapProgram $bin/bin/crystal \
              --suffix PATH : ${lib.makeBinPath [ pkg-config llvmPackages.clang which ]} \
              --suffix CRYSTAL_PATH : lib:$lib/crystal \
              --suffix CRYSTAL_LIBRARY_PATH : ${
                lib.makeLibraryPath (commonBuildInputs extraBuildInputs)
              }
            install -dm755 $lib/crystal
            cp -r src/* $lib/crystal/
  
            install -dm755 $out/share/doc/crystal/api
            cp -r docs/* $out/share/doc/crystal/api/
            cp -r samples $out/share/doc/crystal/
  
            install -Dm644 etc/completion.bash $out/share/bash-completion/completions/crystal
            install -Dm644 etc/completion.zsh $out/share/zsh/site-functions/_crystal
  
            install -Dm644 man/crystal.1 $out/share/man/man1/crystal.1
  
            install -Dm644 -t $out/share/licenses/crystal LICENSE README.md
  
            mkdir -p $out
            ln -s $bin/bin $out/bin
            ln -s $lib $out/lib
  
            runHook postInstall
          '';
  
          enableParallelBuilding = true;
  
          dontStrip = true;
  
          checkTarget = "compiler_spec";
  
          preCheck = ''
            export HOME=/tmp
            mkdir -p $HOME/test
  
            export LIBRARY_PATH=${lib.makeLibraryPath checkInputs}:$LIBRARY_PATH
            export PATH=${lib.makeBinPath checkInputs}:$PATH
          '';
  
          passthru.buildCrystalPackage = callPackage ./build-package.nix {
            crystal = compiler;
          };
  
          meta = with lib; {
            description = "A compiled language with Ruby like syntax and type inference";
            homepage = "https://crystal-lang.org/";
            license = licenses.asl20;
            maintainers = with maintainers; [ david50407 fabianhjr manveru peterhoeg ];
            platforms = builtins.attrNames archs;
          };
        })
    );
  
  in rec {
    binaryCrystal_0_31 = genericBinary {
      version = "0.31.1";
      sha256s = {
        x86_64-linux  = "0r8salf572xrnr4m6ll9q5hz6jj8q7ff1rljlhmqb1r26a8mi2ih";
        i686-linux    = "0hridnis5vvrswflx0q67xfg5hryhz6ivlwrb9n4pryj5d1gwjrr";
        x86_64-darwin = "1dgxgv0s3swkc5cwawzgpbc6bcd2nx4hjxc7iw2h907y1vgmbipz";
      };
    };
  
    crystal_0_31 = generic {
      version = "0.31.1";
      sha256  = "1dswxa32w16gnc6yjym12xj7ibg0g6zk3ngvl76lwdjqb1h6lwz8";
      doCheck = false; # 5 checks are failing now
      binary = binaryCrystal_0_31;
    };
  
    crystal_0_32 = generic {
      version = "0.32.1";
      sha256  = "120ndi3nhh2r52hjvhwfb49cdggr1bzdq6b8xg7irzavhjinfza6";
      binary = crystal_0_31;
    };
  
    crystal_0_33 = generic {
      version = "0.33.0";
      sha256  = "1zg0qixcws81s083wrh54hp83ng2pa8iyyafaha55mzrh8293jbi";
      binary = crystal_0_32;
    };
  
    crystal_0_34 = generic {
      version = "0.34.0";
      sha256  = "110lfpxk9jnqyznbfnilys65ixj5sdmy8pvvnlhqhc3ccvrlnmq4";
      binary = crystal_0_33;
    };
  
    crystal_0_35 = generic {
      version = "0.35.1";
      sha256  = "0p51bjl1nsvwsm64lqq421dcsxa201w7wwq8plw4r8wqarpq0g69";
      binary = crystal_0_34;
      # Needs git to build as per https://github.com/crystal-lang/crystal/issues/9789
      extraBuildInputs = [ git ];
    };
  
    crystal_0_36 = generic {
      version = "0.36.0";
      sha256  = "0s7g13mrh2jrxxrrrg4hy3gi49rp7fmpn9zg9kj4nbc8w8yir20r";
      binary = crystal_0_35;
    };
  
    crystal = crystal_0_36;
  
    crystal2nix = callPackage ./crystal2nix.nix {};
  }
  
negative.code: , fetchFromGitHub
  , fetchurl
  , lib
    # Dependencies
  , boehmgc
  , coreutils
  , git
  