As the other comments have already mentioned, it interferes with itself, so you still observe the same interference patterns [0] [1]. Which admittedly seems impossible at first, but so does the rest of quantum physics.

[0]: https://www.feynmanlectures.caltech.edu/III_01.html#Ch1-S5

[1]: https://en.wikipedia.org/wiki/Wave%E2%80%93particle_duality#...