https://issues.dlang.org/show_bug.cgi?id=22511
--- Comment #2 from Dlang Bot <dlang-bot@dlang.rocks> --- @omerfirmak created dlang/phobos pull request #8318 "Merge PR #8315 & #8316 in to `stable`" fixing this issue: - Fix Issue 22511 - Add explicit copy ctor for Nullable https://github.com/dlang/phobos/pull/8318 --