It didn't make the class implicitly shared, but required an additional heap allocation on construction and copy, as it used 'only' QScopedPointer. As it's private API the pimpl is also not needed for BC reasons. So inline the data members, and some trivial accessors. As a by-product of removing the copy special member functions, we gain nothrow move special member functions. Interestingly, the memory layout of a QList<QMimeMagicRule> (replacing which is the topic of a future patch) doesn't change due to this change, because the type that formerly fit QList very well now is too large. But copying the type outside QList now no longer allocates memory. Saves more than 2.5KiB in text size on optimized GCC 5.3 Linux AMD64 builds. Change-Id: Ie3588cb5693227da6f1bfa196db924e075a750b3 Reviewed-by: David Faure <david.faure@kdab.com>