error: union `CmsgIter` is never used
  --> library/std/src/sys/net/connection/socket/unix.rs:71:11
   |
71 | pub union CmsgIter<'buf> {
   |           ^^^^^^^^

error: struct `CmsgIterInner` is never constructed
  --> library/std/src/sys/net/connection/socket/unix.rs:78:8
   |
78 | struct CmsgIterInner<'buf> {
   |        ^^^^^^^^^^^^^

error: struct `CmsgBuf` is never constructed
  --> library/std/src/sys/net/connection/socket/unix.rs:86:12
   |
86 | pub struct CmsgBuf<'buf>(&'buf mut [u8]);
   |            ^^^^^^^

error: associated functions `new` and `new_unchecked` are never used
  --> library/std/src/sys/net/connection/socket/unix.rs:90:12
   |
88 | impl<'buf> CmsgBuf<'buf> {
   | ------------------------ associated functions in this implementation
89 |     // fails if buf isn't aligned to alignof(cmsghdr)
90 |     pub fn new(buf: &'buf mut [u8]) -> io::Result<Self> {
   |            ^^^
...
98 |     pub unsafe fn new_unchecked(buf: &'buf mut [u8]) -> Self {
   |                   ^^^^^^^^^^^^^

error: methods `recv_msg` and `send_msg` are never used
   --> library/std/src/sys/net/connection/socket/unix.rs:423:12
    |
128 | impl Socket {
    | ----------- methods in this implementation
...
423 |     pub fn recv_msg<'a, 'b, T>(
    |            ^^^^^^^^
...
486 |     pub fn send_msg<T>(
    |            ^^^^^^^^