On Win7 64bit with Python 3.5.1 (64bit) and PyQt5 (Qt 5.6) and PyCharm Community 2016.1.4 I get the "unresolved reference" warning in PyCharm for
from PyQt5 import QtWidgets
while if I run the script it runs just fine. Re-indexing doesn't help but funnily this works:
without warning (and runs too). PyCharm seems to get something wrong.