How to refer to Swift's `Clock` type in a generic type parameter constraint?

[Danny]

Implicitly imported types & namespace priority

_Concurrency.Task is the correct invocation. the underscore is part of the module name, do not fear the underscore just because it’s there. however, you may eventually experience some source breakage once the core team decides to drop the underscore, similar to _Distributed -> Distributed. but this would also happen if you used the typealias.