I spent a bunch of time looking at https://docs.rs/winapi/0.3.7/x86_64-pc-windows-msvc/winapi/um/fileapi/struct.BY_HANDLE_FILE_INFORMATION.html, seeing that there was a Default implementation for the type, and then hitting errors when trying to call BY_HANDLE_FILE_INFORMATION::default() in code that was using winapi 0.3.7. Eventually I clicked on https://docs.rs/winapi/0.3.7/x86_64-pc-windows-msvc/src/winapi/macros.rs.html#381 and realized that the implementation is only generated if the impl-default feature is enabled. I think it would be very helpful to expose information about conditional compilation in the generated documentation somehow in order to avoid problems like this in the future.