My initial inclination is to agree with Stefan. At the moment, we have a
slightly leaky abstraction where the exceptions used mean that coroutines
still expose the fact that under the covers they're defined in terms of
generator semantics.

However, that leak in the abstraction reveals an underlying truth -
coroutine semantics *are* derived from generator semantics, and they *do*
share common underlying infrastructure.

We may eventually find pragmatic reasons for wanting to plug that leak and
use separately named exceptions, but unlike the situation with coroutines
themselves, I'm not currently seeing a clear gain in either usability or
comprehensibility as a payoff for the extra complexity.