{"ast_node_type":"variable","tokens":[{"end":66,"kind":"keyword","start":0,"text":"let"}]}
                let b_offset = a_size.align_to(b.align(self).abi);
                let (a_size, b_size) = (a.size(self), b.size(self));
                assert!(b_offset.bytes() > 0); // in `operand_field` we use the offset to tell apart the fields