Tests on aarch64 + cpython3.10-dev have started failing

[mattip]

Is this due to a stale cache? For instance, here

./../builds/venv/lib/python3.10/site-packages/mypy/types.py:14: in <module>

    import mypy.nodes

../../builds/venv/lib/python3.10/site-packages/mypy/nodes.py:14: in <module>

    import mypy.strconv


../../builds/venv/lib/python3.10/site-packages/mypy/strconv.py:10: in <module>

    from mypy.visitor import NodeVisitor
../../builds/venv/lib/python3.10/site-packages/mypy/visitor.py:18: in <module>

    class ExpressionVisitor(Generic[T]):

/opt/python/3.10-dev/lib/python3.10/typing.py:287: in inner

    return cached(*args, **kwds)


/opt/python/3.10-dev/lib/python3.10/typing.py:1166: in __class_getitem__

    return _GenericAlias(cls, params)


/opt/python/3.10-dev/lib/python3.10/typing.py:874: in __init__

    self.__parameters__ = _collect_type_vars(params)

../../builds/venv/lib/python3.10/site-packages/typing_extensions.py:146: in _collect_type_vars

    if _should_collect_from_parameters(t):

../../builds/venv/lib/python3.10/site-packages/typing_extensions.py:120: in _should_collect_from_parameters

    t, (typing._GenericAlias, _types.GenericAlias, _types.UnionType)

E   AttributeError: module 'types' has no attribute 'UnionType'

[BvB93]

Is this due to a stale cache?

Seems to be so, a 3.10.0 alpha build is being used according to the log:

$ python --version
Python 3.10.0a5+

[mattip]

I deleted all the caches at https://app.travis-ci.com/github/numpy/numpy/caches, let's see if that helps

[charris]

Maybe change 3.10-dev to 3.10? I tried that a while ago and 3.10 wasn't yet available, but maybe now.