Earlier quoted context omitted.
That's an interesting point. From a strictly theoretical perspective you're right. I think it's that generics are more abstract and have a higher blast radius. Eg, you add an argument to a method, you need to update usage of that method. You add a generic to a class, you need to update everywhere that class is used. The fact that arguments are less abstract also I believe tends to prevent them from bubbling all the w…
> you add an argument to a method, you need to update usage of that method. You add a generic to a class, you need to update everywhere that class is used. You're talking about two different things here, though. What if you add a generic parameter to a function? It'll often be inferred at existing call sites, but worst case, same as any other change to a function's signature.
In the worst case, adding a nongeneric parameter to a function could have the same impact. I've never heard of that happening though. I'm trying to express how I've observed things working in practice, not the theoretical boundaries of what could happen here.
So lets say you add a concrete parameter to a method. You update the usages. Somewhere the output gets stored in an existing class. So you add a new field to this class of the correct type. You're done.
Let's say you do the same with a generic. Now when you add that field to that class, it also has to be generic over that type. Now you need to update all the places where that class was used.
If your code is overly generic throughout, the likelihood of this having secondary or tertiary effects and having a runaway refactor becomes pretty darn high.
Being too abstract will always get you in trouble, and it'll probably look pretty similar. I'm just saying it's very easy to do with generics and harder to do with less abstract techniques.