This isn't a bug report, but rather a helpful tool that might save folks moving from annotations to attributes a lot of time.

Rector has a tool that can automatically migrate annotations to attributes, so long as you provide the class mapping for it.

Here's a sample script I set up that (crudely) does the migration from annotations to attributes:

https://gist.github.com/BusterNeece/230f1bf619740b0564b88a69978de82c

It's not perfect, but it gets you to a really good starting point and takes care of a task that is extremely boring to do otherwise.

Edit: See below for a link to a repo that does this in an improved manner!