As an aside, it's just silly to make the repository a bunch of checked-in patches. Git already does revision control. You don't need to do revision control in your revision control.
I wanted everything in one repo and this worked well enough. For presenting to rust compiler team I forked the repos in question and made branches for review with the patches.
Disagree. This was incredibly easy to test in a Bazel monorepo due to the ability to inject patch files into 3rd party dependencies (https://bazel.build/rules/lib/globals/module#parameters-13).