Per Cory's comments, that looks like an 'acceptable' failure. The idea being, Swift isn't needed for a production deploy (so all of the actual code must use lazy loading). But, for developers, Swift is required to run the unit-tests to prevent integration/regression bugs.
> Was swift removed from the pip-requires file?
Not that I'm aware of.
Per Cory's comments, that looks like an 'acceptable' failure. The idea being, Swift isn't needed for a production deploy (so all of the actual code must use lazy loading). But, for developers, Swift is required to run the unit-tests to prevent integration/ regression bugs.