> On the other hand, 3 months + 2 lightyears is ill-typed, because the right-hand side is of type Length. You can change ‘years’ to ‘lightyears’ in the example

> On the other hand, 3 months + 2 lightyears is ill-typed, because the right-hand side is of type Length. You can change ‘years’ to ‘lightyears’ in the example above to see the resulting compiler error. Why not both? Make lightyears both Length and Time