{"ast_node_type":"other","tokens":[{"end":44,"kind":"keyword","start":0,"text":"//"}]}
                // `Pin::new_unchecked(...)`
                let iter = self.expr_ident_mut(head_span, iter_ident, async_iter_pat_id);
                let iter = self.arena.alloc(self.expr_call_lang_item_fn_mut(