They could. The halting problem is solved (well, worked around) by adding a complete type system, which the compiler is free to implement. But with respect to

They could. The halting problem is solved (well, worked around) by adding a complete type system, which the compiler is free to implement. But with respect to this discussion the compiler does not need to solve the halting problem. It can assume the program always halts. It makes no difference if the program actually halts or not.