Vertices appear with a slight Y offset?

[FredYeye]

Hi! I'm having this strange issue where drawing some simple things with openGL appear to get a tiny Y offset (tenth of a pixel or so?). I'm asking here and not submitting an issue because... well, i don't know if this is winit's doing 🤷 so gotta start somewhere here.

I've made a repo that creates a window and draws a square to demonstrate the problem: https://github.com/FredYeye/offset-vertices

Picture of running the program:

As you can see if you zoom in, the box gets interpolated on the top and bottom. For now i figured out a really dumb fix, I shift everything up by adding a tiny Y offset in the translation matrix (shader.vert, line 21)...
Anyone have any idea of where this offset is coming from?

[kchibisov]

winit has nothing to do with OpenGL or can affect OpenGL in any way(it has zero graphics code). Consult the OpenGL documentation/standard on that matter.