When using the -profile flag phobos unit tests fail (Ubuntu 16.04 - DMD64 D Compiler v2.071.0) For example, when following these steps I get a failed unit test: $ cd /usr/include/dmd/phobos/std/ $ rdmd --force -I/usr/include/dmd/phobos/std -I/usr/include/dmd/phobos/core -main -unittest -profile format.d Without the -profile flag it works. I only tried the format module, others may be affected.
There have been a couple of fixes in regards with the cycle detection of Phobos, so this might have been fixed during that. I just tried it on my machine & it worked fine. Please reopen if it's still an issue on your machine.