The trouble with symbolic links

One of the things I appreciate in Rust is that where there are special cases somebody takes the time to think about whether in fact there's some more general principle of which the special case was just the easy to observe part, the tip of the iceberg so to say, and to provide for the general principle, rather than just the special case.

Example: If you're a Rust beginner you learn that Option's None and Result's Error can be passed back up to your caller where appropriate with the '?' try operator and this seems like a special case, you can't go around treating an integer, or a file handle, or some other kind of thing this way. Or can you? In fact the general principle is the (nightly gated) Try trait, and Option and Result merely implement Try (they're allowed to do this even in stable Rust because Rust internally isn't subject to its own stability rules or it'd be recursively impossible to develop anything)

Another example: In languages with ad hoc polymorphism ("Function overloading") it's obvious that "LWN.net".contains("LWN") and "LWN.net".contains('.') are both reasonable things to write so you just overload the function to do either. Rust doesn't have ad hoc polymorphism, so it must decide what type that parameter is such that both "LWN" and '.' match or else provide two functions with different names. The resulting trait Pattern once again represents a more general principle - any pattern which could match parts of a string, and so in Rust you can also write "LWN.net".contains(char::is_alphabetic) because hey, char::is_alphabetic is a function which matches parts of a string so why not.

I think SUID just isn't one of those things, it's a profoundly special case, and so we should immediately be prejudiced against it as a design feature of the operating system. Rather than everything just falling out naturally, as we'd like for a general solution, SUID means everywhere we need to handle this differently. If you've just written a bunch of low level code there's a good chance that if I remind you that SUID exists you'll need to go back and add a bunch of conditional branches to handle that...