Up until recently, LLDB would always use a ClangASTContext, regardless which language was specified in DWARF. While this is not a perfect solution for Rust programs, it at least enabled LLDB to step through them and display variable contents. Until there is a proper Rust language plugin for LLDB, we'd like to keep this behavior so that user can keep using LLDB with the restricted but useful feature set available up until a few months ago.
If you could commit that for me, that'd be great! I might be interested in getting commit access when work on a Rust plugin has begun, but for now I'm good without. Thanks again for your help throughout the process.