Code review comment for lp://qastaging/~mir-team/mir/public-cookie-api

> @"* I guess gcc 4.* assume const for auto = make_unique<..> which causes
> issues when attempting to return a derived class to a base class. You cannot
> return a const unique_ptr since it cannot be std::moved"
>
> I guess you're wrong: that would make auto support implausibly broken.

Re looking at the compiler error... just looks like problem with implicit conversions? Not sure how removing the auto fixed it for me now though :(
https://jenkins.qa.ubuntu.com/job/mir-clang-vivid-amd64-build/4576/console