A new image of the OnePlus 7 has leaked online confirming previous leaks of a notch-less fullscreen display. We also do not see any punch-hole for the selfie camera indicating the possibility of a slider mechanism. However, the display orientation throws up a speculation as to whether or not OnePlus is building support for inverted displays into Oxygen OS.
https://www.notebookcheck.net/New-OnePlus-7-image-leak-confirms-fullscreen-display-devoid-of-any-notch-or-punch-hole.410251.0.html