What happened to Collection protocol recently that this no longer compiles?

[xwu (Xiaodi Wu)]

Protocol conformance stopped working in Xcode 13

All right, so there's a few things I can help with here. I could just tell you straight-up what you need to do to fix this error, but I'm going to try to do you one better by teaching you the skills you'll need to understand and address the problem yourself going forward, step by step. First, how do you understand the error you've been given? Notice that there's a series of error messages that look similar and complain about the same missing requirement, but that not all of them refer to Range…