New submission from Isaac Elliott: In Python 3.5 and 3.6 (at least), the language reference presents a grammar that disallows assignment to literals.
For example, `(a for 1 in [1,2,3])` is a syntax error, as is `(1, a) = (2, 3)`. However the grammar doesn't prevent assignment to subscripted or sliced literals. For example neither `(a for [1,2,3][0] in [1,2,3])` nor `([1,2,3][0], a) = (2, 3)` are considered syntax errors. Similar behavior is exhibited for slices. The problem is that the `target_list` production (https://docs.python.org/3.5/reference/simple_stmts.html#grammar-token-target_list) reuses the `subscription` and `slicing` productions which both use the `primary` production, allowing literals on their left side. ---------- messages: 300740 nosy: Isaac Elliott priority: normal severity: normal status: open title: Assigning to subscript/slice of literal is permitted type: behavior versions: Python 3.5, Python 3.6 _______________________________________ Python tracker <rep...@bugs.python.org> <http://bugs.python.org/issue31263> _______________________________________ _______________________________________________ Python-bugs-list mailing list Unsubscribe: https://mail.python.org/mailman/options/python-bugs-list/archive%40mail-archive.com
