Question

what happens if an eraser is used on a smart object in photoshop?
nothing happens
an error occurs
a prompt appears to rasterize the object
it erases

Explanation:

Smart Objects in Photoshop are vector - like layers. When an eraser tool is used on them, Photoshop prompts to rasterize the object first because the eraser works on pixel - based data. Rasterizing converts the Smart Object into a regular pixel - based layer so the eraser can operate.

Answer:

A prompt appears to rasterize the object