winapi broken in recent nightly

[retep998]

error: attempt to shift left with overflow
   --> src\macros.rs:350:29
    |
350 |                   let mask = ((1 << ($r.end - $r.start)) - 1) << $r.start;
    |                               ^^^^^^^^^^^^^^^^^^^^^^^^^^
    | 
   ::: src\shared\d3dukmdt.rs:257:1
    |
257 | / BITFIELD!{D3DDDICB_LOCK2FLAGS Value: UINT [
258 | |     Reserved set_Reserved[0..32],
259 | | ]}
    | |__- in this macro invocation
    |
    = note: `#[deny(const_err)]` on by default

Using rustc 1.40.0-nightly (7979016af 2019-10-20)

[jonas-schievink]

cc @oli-obk

[Centril]

and cc @wesleywiser

[wesleywiser]

I assume in this context UINT is a 32-bit unsigned integer? If so, the lint appears to be triggering correctly. This has likely started triggering because of some recent improvements to the ConstProp pass.

I believe this behavior is covered under RFC 1129 so this is expected behavior.

If you want to continue using this code as is, you can either add #![warn(const_err)] or #![allow(const_err)] to the appropriate module.

This won't break crates dependent on winapi since cargo passes --cap-lints allow to rustc when compiling dependencies.

[oli-obk]

It may also have started getting reported due to #65320 which makes sure that we report const_err even if the code causing the lint to trigger is part of a macro from another crate.

Closing as wontfix because this is the expected behaviour and is easily silenced by an allow attribute.