indexIn() could hit UB if `from` < 0, so handle that case too. (This also makes using noexcept for that method more correct wrt the Lakos rule). While I think that passing valid indexes to a method is the responsibility of the caller and that the existing API in Qt where a negative index is interpretted as "search from the end" is hard-to-use/bad API, not handling `from < 0` this way will most likely not pass review (c.f. commit 81538c5219b92356c52233a80845847145795d6f on gerrit). I'd rather get this over with so that an indexIn(QSV) overload can be added... Change-Id: Id85d18c901c82d9652804ecff7bfe7c71c10a63c Reviewed-by: Thiago Macieira <thiago.macieira@intel.com>