def visit_default(self, node: LN) -> Iterator[Line]:
        """Default `visit_*()` implementation. Recurses to children of `node`."""
        if isinstance(node, Leaf):
            any_open_brackets = self.current_line.bracket_tracker.any_open_brackets()
            for comment in generate_comments(node):
                if any_open_brackets:
                    # any comment within brackets is subject to splitting
                    self.current_line.append(comment)
                elif comment.type == token.COMMENT:
                    # regular trailing comment
                    self.current_line.append(comment)
                    yield from self.line()

                else:
                    # regular standalone comment
                    yield from self.line()

                    self.current_line.append(comment)
                    yield from self.line()

            if any_open_brackets:
                node.prefix = ""
            if node.type not in WHITESPACE:
                self.current_line.append(node)
        yield from super().visit_default(node)
Default `visit_*()` implementation. Recurses to children of `node`.
src/black/linegen.py