[BUG] - Casting between integer sizes

[Jamesbarford]

Describe the bug
Sometimes casting between I32's and I64's can explode. Or give a very wrong number.

To Reproduce
This might have been fixed so is difficult/impossible to reproduce. Typically it occurs when a function argument is a different integer size from the integer being passed into the called function.

Example Program

U0 PrintInt(U16 x)
{
  "%d\n";
}

U0 Main()
{
  I64 d = 34;
  PrintInt(d); // prints an extremely large negative number
}

Expected behavior
A C-like integer conversion should happen. This is a bit vague but boils down to "do what C does" which then leads to C-like behaviour than something completely unexpected which is what happens now.