Double dict unpacking does not parse

[not-raspberry]

$ python -c "a = {'a': 1}
b = {'b': 2}
print(dict(**a, **b))
"
{'a': 1, 'b': 2}

$ mypy -c "a = {'a': 1}
b = {'b': 2}
print(dict(**a, **b))
"
<string>:3: error: Parse error before **

$ python --version
Python 3.5.2

$ mypy --version
mypy 0.4.5

[not-raspberry]

#2086