Some return values can be assigned to a `const auto`, somewhere `dir` is mutated so the whole result has to be assigned to a non `const` variable and once only dir is used, so structured binding isn't used there.
Some return values can be assigned to a `const auto`, somewhere `dir` is mutated so the whole result has to be assigned to a non `const` variable and once only dir is used, so structured binding isn't used there.