git branch -D won't delete the branch you're on

Hello,

Minor nitpick, that is not dreadfully important, but now that we have the detached HEAD facility, is it reasonable to expect this to work?

 $ git checkout -b somebranch HEAD^
 $ git branch -d somebranch
 error: Cannot delete the branch 'testcvs' which you are currently on.

Especially given that this will work (albeit with a warning):

 $ git checkout HEAD^
 warning: you are not on ANY branch anymore.
 If you meant to create a new branch from the commit, you need -b to
 associate a new branch with the wanted checkout.  Example:
   git checkout -b <new_branch_name> HEAD^

Andy