These are just typing hints, they don't break compatibility. The ability to annotate function parameters and return values has been there for a while, so PyPy c

These are just typing hints, they don't break compatibility. The ability to annotate function parameters and return values has been there for a while, so PyPy can at first just ignore these annotations and any valid python 3.5 program is also a valid PyPy program. Given that PyPy already does type-specialisation for optimisation, I assume its authors will want to make use of the type hints anyway, so we can expect, that support for this feature will land shortly in PyPy.