Theano/Theano — pull request #1691 by SuperElectric (2014-01-08 12:03:39+00:00)
Title: Bugfix in sparse.hstack(), sparse.vstack()

There was a bug that would cause sparse.hstack() and vstack() to crash when called without a dtype arg. It was calling scalar.upcast(arglist), instead of scalar.upcast(*arglist). This is a simple 2-line fix.