On the way to remove most packages depending on Python2.7, I failed to remove virtual/python-singledispatch. The following packages still pull in virtual/python-singledispatch although they are not installed for Python2.7. dev-python/mergedict dev-python/numba dev-python/rpy net-misc/livestreamer net-misc/streamlink www-servers/tornado
It is not a bug for packages to depend a virtual which may be more than one package. Even if it the language itself. See all the perl virtuals for reference