I think you're missing a subtlety of my argument. I'm not saying you never need to pick a container that isn't a simple hash table, or design a DSL, or roll your own event loop, or design a hierarchy of abstractions. I've done all of those things in Golang --- even the event loop!

But in C++, those are decisions you might make in parsing a config file, or in managing a simple table of sessions, or adding an LRU cache to something. You can't get away from the decisions. I have an array of stuff, and I have to decide, "do I want a list, an slist, a vector, or a deque, and what the fuck is a deque?". 98% of the time there is one sane decision that is so close to optimal that it's not worth tinkering with.

In Go, for prosaic, routine code, those decisions have been made for you. You have to go just annoyingly enough out of your way to second-guess those decisions that you almost never do, and you're almost always better off for not having to do it.

> You can't get away from the decisions. I have an array of stuff, and I have to decide, "do I want a list, an slist, a vector, or a deque, and what the fuck is a deque?". 98% of the time there is one sane decision that is so close to optimal that it's not worth tinkering with.

I'm currently working on a project (WebRender) in which we keep using the standard library hash table in the first cut of code whenever we need an associative lookup table, and every time we use it it keeps coming up #1 in the profile. Almost every single time. We then have to switch to another, more optimized data structure, and generics really help here so that we can reuse these data structures. In fact, if we didn't have them, we'd probably be sunk.

Again, I'm not arguing that we never need custom containers.

I'm saying that some projects need custom containers all the time—to the exclusion of the built-in ones—and need to reuse the implementations of those containers.

So did we! We didn't use Golang's maps to implement limit order books; we used a red-black tree. We did not build our own, nor did we find a red-black tree that was designed for order books.

This just isn't as much of a big deal as people think it is. Go makes it a drag to use a custom container, but it doesn't make it hard, and that might be how it should be!

And you had one data type that you used with that red-black tree, so you didn't mind not being able to abstract over the types of objects you were placing in the container. But we have lots of data types that we reuse for freelists and other types of containers. We don't want to have to reimplement that code for every single type we want. That's where generics save us.

> This just isn't as much of a big deal as people think it is. Go makes it a drag to use a custom container, but it doesn't make it hard, and that might be how it should be!

I believe you that it wasn't a big deal in your case. But I disagree with your general claim. I think you're extrapolating from your use case to claim that generics aren't important (vital, in some cases). I'm saying that, in my use case, they are.