QTextStream is in a corrupted state after reading to end and seeking to 0 - and calling pos() can then corrupt it more

Consider the attached program which is meant to analyze some very basic statistics on the GPL-3 file. However, the pos() call returns -1 instead of the real offset.

In the actual code which this test case is extracted from, and using the file which triggered the condition, I didn't get -1 but a random position in the file which was much later than the position it should have been. And the pos() reset the file position so that the subsequent readLine() calls started with a partial line.

I also tried inserting resetStatus(), reset(), or even reopening the file and then reassigning the IO device, with no changes in behavior.