This reverts commit b7d8c6188986f62573b9516fe27fdd0c7df1aaf9. And This reverts commit 2d40f179124f874aca4cf1145fdbc42fb8fb17f3. It caused a build failure i'll need to reproduce. ` error: could not convert ‘Rule’ from ‘llvm::Regex’ to ‘llvm::Expected<llvm::Regex>’`