Housing with a mall

Have you noticed the vast area and parking lot at the Walmart Shopping Center in North America? I think we should make better use of that space. 

Instead of reducing any part of it, we could construct an apartment building on top of it. Walmart could take charge of the project, and their employees and customers could live there. Since everyone would buy their needs from Walmart, the company would have fixed customers, including others from the city and could earn rent as well. Employees would prefer to stay close to work, saving time, money and energy on travel. 

The basement could be reserved for apartment renters' parking spots, so they wouldn't occupy other shoppers' parking lots. 

Not just Walmart, other shopping malls like Canadian Super Store, Costco, Dollarama, and Metro could also consider constructing such apartments on top of their 3/4 stories shopping centers. This solution wouldn't require any extra space to address the housing problem.

These apartments won't cause extra traffic on the roads for shopping and working (For the employees).