incorrect `useless_deprecated` error on nightly

[davidhewitt]

Code

I tried this code:

unsafe extern "C" {
    #[deprecated]
    static FOO: std::ffi::c_int;
}

fn main() {
    dbg!(unsafe { FOO });
}

I expected to see this happen: successful build, with warning about use of deprecated FOO.

Instead, this happened: build failed, hard error on use of useless_deprecated.

Note that the hard error seems incorrect to me, the warning works fine and always did. cc @JonathanBrouwer @jdonszelmann it looks to me like #145085 is the likely cause.

warning: use of deprecated static `FOO`
 --> src/main.rs:8:19
  |
8 |     dbg!(unsafe { FOO });
  |                   ^^^
  |
  = note: `#[warn(deprecated)]` on by default

error: `#[deprecated]` attribute cannot be used on foreign statics
 --> src/main.rs:3:5
  |
3 |     #[deprecated]
  |     ^^^^^^^^^^^^^
  |
  = warning: this was previously accepted by the compiler but is being phased out; it will become a hard error in a future release!
  = help: `#[deprecated]` can be applied to functions, data types, modules, unions, constants, statics, macro defs, type aliases, use statements, struct fields, traits, associated types, associated consts, enum variants, inherent impl blocks, crates
  = note: `#[deny(useless_deprecated)]` on by default

Version it worked on

It most recently worked on: nightly-2025-08-14, stable 1.89

Version with regression

rustc --version --verbose:

rustc 1.91.0-nightly (898aff704 2025-08-14)
binary: rustc
commit-hash: 898aff704d6f0d00343f21d31b8b9bfac8e43007
commit-date: 2025-08-14
host: aarch64-apple-darwin
release: 1.91.0-nightly
LLVM version: 21.1.0

@rustbot modify labels: +regression-from-stable-to-nightly -regression-untriaged

[JonathanBrouwer]

@rustbot claim
Will take a look and fix this either tonight or tomorrow, this is indeed a bug, thanks for finding it!