René's URL Explorer Experiment

{"@context":"https://schema.org","@type":"DiscussionForumPosting","headline":"PLS incorrectly reports error for self-assignment to local variable","articleBody":"The analyzer incorrectly flags the following (admittedly strange) code with a use-before-def error/warning.\r\n\r\n![screen shot 2018-12-26 at 10 45 46 am](https://user-images.githubusercontent.com/7040122/50454433-6d4c2b80-08fc-11e9-975c-3b431227bf41.png)\r\n\r\nThe problem is due to a somewhat hacky piece of code in `DDG.Walk(AssignmentStatement node)` that attempts to detect the case \"fob = fob\" and temporarily manipulate the scope before evaluating the RHS of the assignment. This hack is problematic for a number of reasons. For example, it doesn't properly handle other more complex expressions like \"fob = fob + 1\".\r\n\r\nI think the preferable solution is to remove the hack but modify the logic to allow _reading_ of symbols in outer scopes even if `VisibleToChildren` is false. This property should probably be renamed `WritableByChildren` since Python allows reading of symbols from outer scopes.\r\n\r\nSee the following documentation in [section 2.1 of the official Python docs](https://docs.python.org/3.7/tutorial/classes.html).\r\n\r\n![screen shot 2018-12-26 at 10 59 02 am](https://user-images.githubusercontent.com/7040122/50454574-46dac000-08fd-11e9-8b95-2f54d76c73aa.png)","author":{"url":"https://github.com/erictraut","@type":"Person","name":"erictraut"},"datePublished":"2018-12-26T19:02:04.000Z","interactionStatistic":{"@type":"InteractionCounter","interactionType":"https://schema.org/CommentAction","userInteractionCount":2},"url":"https://github.com/513/python-language-server/issues/513"}