This clang tidy check checks for classes that violate the rule of five and zero as specified in CppCoreGuidelines: https://github.com/isocpp/CppCoreGuidelines/blob/master/CppCoreGuidelines.md#c21-if-you-define-or-delete-any-default-operation-define-or-delete-them-all.
If a class defines or deletes a default operation then it should define or delete them all.
Since this is an implementation detail, perhaps it can be moved into the source file instead of made a public member of the check?