Regression in that some imports are considered unused, but only when building docs

[retep998]

rustc 1.28.0-nightly (f28c7aef7 2018-06-19)
binary: rustc
commit-hash: f28c7aef7fbff1909c2d0257186cd7a5f0c6aa4b
commit-date: 2018-06-19
host: x86_64-pc-windows-msvc
release: 1.28.0-nightly
LLVM version: 6.0

Output of cargo doc

> cargo doc --all-features
   Compiling winapi v0.3.5 (file:///C:/Users/Peter/Code/winapi-rs)
 Documenting winapi v0.3.5 (file:///C:/Users/Peter/Code/winapi-rs)
error: unused import: `IsEqualGUID`
 --> src\shared\devpropdef.rs:8:29
  |
8 | use shared::guiddef::{GUID, IsEqualGUID};
  |                             ^^^^^^^^^^^
  |
note: lint level defined here
 --> src\lib.rs:8:9
  |
8 | #![deny(unused, unused_qualifications)]
  |         ^^^^^^
  = note: #[deny(unused_imports)] implied by #[deny(unused)]

error: unused import: `USB_ENDPOINT_DIRECTION_MASK`
  --> src\shared\usb.rs:10:59
   |
10 |     PUSB_CONFIGURATION_DESCRIPTOR, USB_DEVICE_DESCRIPTOR, USB_ENDPOINT_DIRECTION_MASK,
   |                                                           ^^^^^^^^^^^^^^^^^^^^^^^^^^^

error: unused imports: `FILE_ANY_ACCESS`, `METHOD_BUFFERED`, `METHOD_NEITHER`
  --> src\shared\usbiodef.rs:13:20
   |
13 | use um::winioctl::{FILE_ANY_ACCESS, FILE_DEVICE_UNKNOWN, METHOD_BUFFERED, METHOD_NEITHER};
   |                    ^^^^^^^^^^^^^^^                       ^^^^^^^^^^^^^^^  ^^^^^^^^^^^^^^

error: unused import: `c_short`
 --> src\shared\windowsx.rs:8:21
  |
8 | use ctypes::{c_int, c_short};
  |                     ^^^^^^^

error: unused imports: `DWORD`, `HIWORD`, `LOWORD`
 --> src\shared\windowsx.rs:9:25
  |
9 | use shared::minwindef::{DWORD, HIWORD, LOWORD, LPARAM};
  |                         ^^^^^  ^^^^^^  ^^^^^^

error: unused import: `um::winbase::LocalFree`
 --> src\um\accctrl.rs:9:5
  |
9 | use um::winbase::LocalFree;
  |     ^^^^^^^^^^^^^^^^^^^^^^

error: unused import: `IMAGE_BITMAP`
  --> src\um\commctrl.rs:22:22
   |
22 |     CB_DELETESTRING, IMAGE_BITMAP, LPSCROLLINFO, LPTRACKMOUSEEVENT, NMHDR,
   |                      ^^^^^^^^^^^^

error: unused import: `shared::winerror::SEVERITY_ERROR`
  --> src\um\dwrite.rs:13:5
   |
13 | use shared::winerror::SEVERITY_ERROR;
   |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^

error: unused imports: `FLOAT`, `HIWORD`, `LOWORD`
  --> src\um\dxva2api.rs:12:38
   |
12 | use shared::minwindef::{BOOL, DWORD, FLOAT, HIWORD, LOWORD, UCHAR, UINT, USHORT};
   |                                      ^^^^^  ^^^^^^  ^^^^^^

error: unused import: `PUCHAR`
  --> src\um\evntcons.rs:11:25
   |
11 | use shared::minwindef::{PUCHAR, PULONG, PUSHORT, UCHAR, ULONG, USHORT};
   |                         ^^^^^^

error: unused import: `IsEqualIID`
 --> src\um\propkeydef.rs:7:23
  |
7 | use shared::guiddef::{IsEqualIID};
  |                       ^^^^^^^^^^

error: unused import: `SEVERITY_ERROR`
  --> src\um\wincodec.rs:21:5
   |
21 |     SEVERITY_ERROR
   |     ^^^^^^^^^^^^^^

error: unused import: `LOBYTE`
  --> src\um\wingdi.rs:11:71
   |
11 |     BOOL, BYTE, DWORD, FLOAT, HGLOBAL, HMETAFILE, HMODULE, HRGN, INT, LOBYTE, LPARAM, LPBYTE,
   |                                                                       ^^^^^^

error: unused imports: `FALSE`, `TRUE`
  --> src\um\wininet.rs:11:18
   |
11 |     BOOL, DWORD, FALSE, FILETIME, INT, LPBYTE,
   |                  ^^^^^
12 |     LPCVOID, LPDWORD, LPVOID, PBYTE, PDWORD, TRUE, WORD,
   |                                              ^^^^

error: unused imports: `HIWORD`, `LOWORD`, `MAKELONG`
  --> src\um\winsock2.rs:16:27
   |
16 |     BOOL, DWORD, FARPROC, HIWORD, INT, LOWORD, LPDWORD, LPHANDLE, LPINT, LPVOID, MAKELONG, UINT,
   |                           ^^^^^^       ^^^^^^                                    ^^^^^^^^

error: unused imports: `HIWORD`, `LOWORD`
  --> src\um\winuser.rs:16:41
   |
16 |     ATOM, BOOL, BYTE, DWORD, HINSTANCE, HIWORD, HKL, HMODULE, HRGN, HWINSTA, INT, LOWORD, LPARAM,
   |                                         ^^^^^^                                    ^^^^^^

error: Compilation failed, aborting rustdoc

error: Could not document `winapi`.

There is nothing in winapi which is conditional on whether the crate is being built as documentation, and these unused imports do not occur when building winapi normally, nor have they ever occurred when building documentation before. This is a very recent regression.

[QuietMisdreavus]

Duplicate of #51661