duplicated_attributes false positive: cfg expressions

[dtolnay]

Lint Name

duplicated_attributes

Reproducer

#[cfg(any(
    all(
        target_os = "linux",
        any(
            target_arch = "aarch64",
            target_arch = "arm",
            target_arch = "hexagon",
            target_arch = "powerpc",
            target_arch = "powerpc64",
            target_arch = "s390x",
            target_arch = "riscv64",
            target_arch = "riscv32"
        )
    ),
    all(
        target_os = "android",
        any(target_arch = "aarch64", target_arch = "arm")
    ),
))]
pub type c_char = u8;

$ cargo clippy
warning: duplicated attribute
  --> src/main.rs:17:13
   |
17 |         any(target_arch = "aarch64", target_arch = "arm")
   |             ^^^^^^^^^^^^^^^^^^^^^^^
   |
note: first defined here
  --> src/main.rs:5:13
   |
5  |             target_arch = "aarch64",
   |             ^^^^^^^^^^^^^^^^^^^^^^^
help: remove this attribute
  --> src/main.rs:17:13
   |
17 |         any(target_arch = "aarch64", target_arch = "arm")
   |             ^^^^^^^^^^^^^^^^^^^^^^^
   = help: for further information visit https://rust-lang.github.io/rust-clippy/master/index.html#duplicated_attributes
   = note: `#[warn(clippy::duplicated_attributes)]` on by default

warning: duplicated attribute
  --> src/main.rs:17:38
   |
17 |         any(target_arch = "aarch64", target_arch = "arm")
   |                                      ^^^^^^^^^^^^^^^^^^^
   |
note: first defined here
  --> src/main.rs:6:13
   |
6  |             target_arch = "arm",
   |             ^^^^^^^^^^^^^^^^^^^
help: remove this attribute
  --> src/main.rs:17:38
   |
17 |         any(target_arch = "aarch64", target_arch = "arm")
   |                                      ^^^^^^^^^^^^^^^^^^^
   = help: for further information visit https://rust-lang.github.io/rust-clippy/master/index.html#duplicated_attributes

Clippy just says "remove this attribute" but doing so would violate the intended meaning of the program.

The case shown as an example of the intended purpose of this lint in https://rust-lang.github.io/rust-clippy/master/index.html#/duplicated_attributes (#[allow(dead_code)] #[allow(dead_code)]) seems like a quite different thing than this one.

Version

rustc 1.79.0-nightly (85e449a32 2024-03-22)
binary: rustc
commit-hash: 85e449a3237e82c9ade8936a82bd4fc64cfe1057
commit-date: 2024-03-22
host: x86_64-unknown-linux-gnu
release: 1.79.0-nightly
LLVM version: 18.1.2

Additional Labels

No response

[dtolnay]

@GuillaumeGomez @blyxyas (the lint is new from #12378)

[GuillaumeGomez]

You're right, it should not check cfg like this.

[SteveLauC]

Here is another false positive case found in Nix:

https://github.com/nix-rust/nix/blob/01cd697b82087730b00bafa60e25fd53b025cfdd/src/sys/statfs.rs#L77-L79

#[cfg(any(
    target_os = "freebsd",
    target_os = "android",
    all(target_os = "linux", target_arch = "s390x"),
    all(target_os = "linux", target_env = "musl"),
    all(target_os = "linux", target_env = "ohos"),
    all(
        target_os = "linux",
        not(any(target_arch = "s390x", target_env = "musl"))
    ),
))]
#[derive(Eq, Copy, Clone, PartialEq, Debug)]
pub struct FsType(pub fs_type_t);

Clippy suggests me to remove these "duplicate" linux attributes even though that they are actually not the same thing.

Full log here: https://github.com/nix-rust/nix/blob/01cd697b82087730b00bafa60e25fd53b025cfdd/src/sys/statfs.rs#L77-L79

[tamird]

There's also a false positive when using https://crates.io/crates/test-case.

#[test_case("pointer", false, None, 42)]
#[test_case("pointer", true, None, 21)]
#[test_case("struct_flavors", false, None, 1)]
#[test_case("struct_flavors", true, None, 2)]
fn relocation_tests(
    program: &str,
    with_relocations: bool,
    required_kernel_version: Option<(KernelVersion, &str)>,
    expected: u64,
) {
  ...
}

help: remove this attribute
  --> test/integration-test/src/tests/btf_relocations.rs:23:30
   |
23 | #[test_case("pointer", true, None, 21)]
   |                              ^^^^
   = help: for further information visit https://rust-lang.github.io/rust-clippy/master/index.html#duplicated_attributes

warning: duplicated attribute
  --> test/integration-test/src/tests/btf_relocations.rs:24:38
   |
24 | #[test_case("struct_flavors", false, None, 1)]
   |                                      ^^^^
   |
note: first defined here
  --> test/integration-test/src/tests/btf_relocations.rs:12:40
   |
12 | #[test_case("enum_unsigned_32", false, None, 0xAAAAAAAA)]
   |                                        ^^^^
help: remove this attribute
  --> test/integration-test/src/tests/btf_relocations.rs:24:38
   |
24 | #[test_case("struct_flavors", false, None, 1)]
   |                                      ^^^^
   = help: for further information visit https://rust-lang.github.io/rust-clippy/master/index.html#duplicated_attributes

warning: duplicated attribute
  --> test/integration-test/src/tests/btf_relocations.rs:25:37
   |
25 | #[test_case("struct_flavors", true, None, 2)]
   |                                     ^^^^
   |
note: first defined here
  --> test/integration-test/src/tests/btf_relocations.rs:12:40
   |
12 | #[test_case("enum_unsigned_32", false, None, 0xAAAAAAAA)]
   |                                        ^^^^
help: remove this attribute
  --> test/integration-test/src/tests/btf_relocations.rs:25:37
   |
25 | #[test_case("struct_flavors", true, None, 2)]
   |                                     ^^^^
   = help: for further information visit https://rust-lang.github.io/rust-clippy/master/index.html#duplicated_attributes

warning: `integration-test` (lib test) generated 9 warnings

[GuillaumeGomez]

Normally #12555 should fix both your cases since it's a late pass expansion, but please double-check @tamird once it's merged and the new clippy version published.

[tamird]

@GuillaumeGomez it'd be helpful if you pinged this issue when a new nightly is out with this fix.