The PR https://github.com/dlang/tools/pull/194 got reverted due to a regression. As rdmd is a widely used tool reviving it would have a positive impact on many people. FWIW it seems that integrating rdmd into dmd is still far ahead in the future.
Duplicate of 16431 which has moved to https://github.com/dlang/tools/issues/413 *** This issue has been marked as a duplicate of issue 16431 ***