Caused by commit 01301b0b34, which made
vector.resize(vector.size()) not to detach, which was used by fill() and
assumed that detaching happened. The test does not test the resize()
behavior, only that fill() is not broken anymore.
[ChangeLog][QtCore][QVector] Fixed a regression that caused fill() not
to detach, corrupting shared copies.
Fixes: QTBUG-77058
Change-Id: I6aed4df6a12e43c3ac8efffd15b1b527a8007bf3
Reviewed-by: Marc Mutz <marc.mutz@kdab.com>
8abbbb4c48