1A documentation comment that doesn't document anything was found.23Erroneous code example:45```compile_fail,E05856fn main() {7    // The following doc comment will fail:8    /// This is a useless doc comment!9}10```1112Documentation comments need to be followed by items, including functions,13types, modules, etc. Examples:1415```16/// I'm documenting the following struct:17struct Foo;1819/// I'm documenting the following function:20fn foo() {}21```