如果我正在阅读 http://darcs.haskell.org/cabal-install/Distribution/Client/HttpUtils。 hs 正确，您应该可以将环境变量HTTP_PROXY设置为无效值（有效吗？），使其直接运行。

If I'm reading http://darcs.haskell.org/cabal-install/Distribution/Client/HttpUtils.hs correctly, you should be able to set the environment variable HTTP_PROXY to an invalid value (would "" work?) to get it to go direct.