On Tue, Oct 9, 2012 at 1:14 PM, Guido van Rossum <gu...@python.org> wrote: > Maybe we should do something more drastic and always create a new, > unique constant whenever a literal occurs as an argument of 'is' or > 'is not'? Then such code would never work, leading people to examine > their code more closely. I betcha we have people who could change the > bytecode compiler easily enough to do that. (I'm not seriously > proposing this, except as a threat of what we could do if the > SyntaxWarning is rejected. :-)
That wouldn't guarantee that the code would never work, merely that the 'is' checks would be never true. Dangerous if the condition is a guard for an unusual condition. A unit test could of course catch it, but that assumes that everyone who writes "if x is 0" has tests probing both branches of that check... ChrisA -- http://mail.python.org/mailman/listinfo/python-list
