Class DetectBadNodes

Tools/clinic/libclinic/dsl_parser.py:973–992

                    # detect whether default is okay, via a denylist
                    # of disallowed ast nodes.
                    class DetectBadNodes(ast.NodeVisitor):
                        bad = False
                        def bad_node(self, node: ast.AST) -> None:
                            self.bad = True

                        # inline function call
                        visit_Call = bad_node
                        # inline if statement ("x = 3 if y else z")
                        visit_IfExp = bad_node

                        # comprehensions and generator expressions
                        visit_ListComp = visit_SetComp = bad_node
                        visit_DictComp = visit_GeneratorExp = bad_node

                        # literals for advanced types
                        visit_Dict = visit_Set = bad_node
                        visit_List = visit_Tuple = bad_node

                        # "starred": "a = [1, 2, 3]; *a"
                        visit_Starred = bad_node

                    denylist = DetectBadNodes()
                    denylist.visit(expr)