This is a bit of a special case in that I'm wary about providing a std::mutex which sounds like it's "the mutex" for rust, when in fact it's the last thing you should resort to.

I think what with the std facade this will end up finding its own place, but for now it may want to continue to live in unstable while it still exists.

I think we should continue moving things out of unstable. If it needs a better name, that's fine, but there is no reason for stop energy on this patch.

If we must move it, let's please add it to std::os with a very very clear warning that you are not supposed to use it.

Maybe something like std::internals could replace unstable?

Ahh, that's right. I forgot it's not the public mutex. std::internals definitely sounds like a more appropriate name for it.

Let's not start with std::internals because that's basically the same thing as std::unstable. Perhaps the best location is std::rt for now.

Ok, I'll move it to std::rt did you still want a re-export under std::unstable?

I think it's fine to move it out of std::unstable permanently. You'll need to reword the commit message for the breaking change, however.

@alexcrichton Moved it to rt and added a proper commit message.

Could you expand a bit on the rationale for why this module is moving? It's useful to put it directly in the commit message rather than indirectly through some links.

@alexcrichton Done.

(needs a rebase)

Could you also put a newline before "This is to cleanout..."

@alexcrichton Done.

Oops, didn't see that this failed. I'll get this fixed.

@alexcrichton Fixed the failing build. Tests pass on my end.

Needs another rebase.

@huonw Sorry, didn't get a notification on this PR. Rebased.