I've asked the same question on StackOverflow, but it seems to me that it is opinion based and will be ignored. So I ask for advice here:
Since PEP 526 -- Syntax for Variable Annotations <https://www.python.org/dev/peps/pep-0526/> was approved, in Python 3.6+ it is possible to provide type hint information in the form *x: int*, also the PEP says "However, annotating a local variable will cause the interpreter to always make it local to the scope and leaves the variable uninitialized". Therefore in Python 3.6+ it is syntactically legal to write: def outer(): x: int def inner(): nonlocal x x = 10 inner() print(x) while the above snippet is semantically more equivalent to: def outer(): #x def inner(): nonlocal x x = 10 inner() print(x) Which is obviously a *SyntaxError: no binding for nonlocal 'x' found`*, sorry for the pun. Also there is nothing said about this style in PEP 8 and Python 3.6 docs. So should I consider this as a bug, or an implementation detail (side effect), or a wart, or a feature? To clarify the purpose of the question - we can not come to a consensus and I would like to hear your opinion and possible pitfalls, if any, if we choose to use this form in our codebase. With kind regards, -gdg -- https://mail.python.org/mailman/listinfo/python-list
