我执行以下操作：
$ stack exec site clean
Removing _site...
Removing _cache...
Removing _cache/tmp...
接着：
$ stack exec site build
Initialising...
Creating store...
Creating provider...
Running rules...
Checking for out-of-date items
Compiling
updated css/default.css
updated images/haskell-logo.png
[ERROR] Hakyll.Core.Compiler.cached: You are trying to (perhaps indirectly) use `cached` on a non-existing resource: there is no file backing index.html
我怎样才能真正清理我的 hakyll 网站以使其构建？
（这里有更多代码：Hakyll 站点的根是什么？）