Re: WALL-E
3-D printer = Robot? I've seen a bit of press for 3-D printed houses. Just one example.
https://www.dezeen.com/2021/05/06/3d-printed-home-project-milestone-eindhoven/#:~:text=A%20boulder%2Dshaped%20concrete%20house,the%20key%20on%20April%2030.&text=The%20home%20was%20designed%20by,the%20shape%20of%20a%20boulder.
It doesn't seem a big leap that one of these rovers on Mars could have a 3-D printing arm. Water for your slurry becomes the issue.