If the object is shared, instead of detaching, copy characters from "this" to a new object except for the chacters that would be erased, this is more efficient than detaching (which would copy the whole data then erase). - Extend tst_QString::removeIf() to catch a corner-case (that I saw with tst_QByteArray::removeIf()). - Add q_uninitialized_remove_copy_if, which works like std::remove_copy_if but for uninitialized memory like q_uninitialized_relocate_n (but copies rather than relocates/moves). With the same static_assert from q_relocate_overlap_n that the type destructor is non-throwing. Added q_uninitialized_remove_copy_if in this commit rather than a separate one so that it's unittested by its usage in eraseIf(). [ChangeLog][QtCore][QString, QByteArray] Removing characters from a currently shared string or byte array is now done more efficiently Task-number: QTBUG-106181 Task-number: QTBUG-106183 Change-Id: Icc0ed31633cef71d482b97e0d2d20d763163d383 Reviewed-by: Thiago Macieira <thiago.macieira@intel.com>