ref: 9b2d009acc6761a5b9328a69773e20f5ee530b15
parent: bdddb0fe46050fc184e0146819e9840611a0e44d
author: Ori Bernstein <orib@google.com>
date: Fri Aug 3 13:20:53 EDT 2012
Don't die if types have no constraints.
An empty constraint set is equivalent to no constraints implemented,
not a segfault. Treat it as such.