The compiler has deep assumptions about exclusive ownership and moves, which affects destructors and deallocation of objects.

It doesn't actually depend on the borrow checker. All lifetime labels are discarded after being checked. Code generation has no idea about borrow checking. Once the code is checked, it is compiled just like C or C++ would, just assuming the code is valid and doesn't use dangling pointers.

Borrow checker doesn't affect program behavior. It either stops compilation or does nothing at all. It's like an external static analysis tool.