Duplicate warning on some attributes with wrong targets

[JonathanBrouwer]

The following three cases create a hard error AND a warning:

fn main() {
    #[no_mangle] || {};
}

error: `#[no_mangle]` cannot be used on a closure as it has no name
 --> src/main.rs:2:5
  |
2 |     #[no_mangle] || {};
  |     ^^^^^^^^^^^^

warning: `#[no_mangle]` attribute cannot be used on closures
 --> src/main.rs:2:5
  |
2 |     #[no_mangle] || {};
  |     ^^^^^^^^^^^^
  |
  = warning: this was previously accepted by the compiler but is being phased out; it will become a hard error in a future release!
  = help: `#[no_mangle]` can be applied to methods, functions, and statics
  = note: `#[warn(unused_attributes)]` (part of `#[warn(unused)]`) on by default

#[inline]
macro_rules! test {
    () => {}
}

error[E0518]: attribute should be applied to function or closure
 --> src/main.rs:5:1
  |
5 | #[inline]
  | ^^^^^^^^^ not a function or closure

warning: `#[inline]` attribute cannot be used on macro defs
 --> src/main.rs:5:1
  |
5 | #[inline]
  | ^^^^^^^^^
  |
  = warning: this was previously accepted by the compiler but is being phased out; it will become a hard error in a future release!
  = help: `#[inline]` can only be applied to functions
  = note: `#[warn(unused_attributes)]` (part of `#[warn(unused)]`) on by default

#[no_mangle] pub const RAH: usize = 5;

warning: `#[no_mangle]` attribute cannot be used on constants
  --> src/main.rs:10:1
   |
10 | #[no_mangle] pub const RAH: usize = 5;
   | ^^^^^^^^^^^^
   |
   = warning: this was previously accepted by the compiler but is being phased out; it will become a hard error in a future release!
   = help: `#[no_mangle]` can be applied to functions and statics
   = note: `#[warn(unused_attributes)]` (part of `#[warn(unused)]`) on by default

error: const items should never be `#[no_mangle]`
  --> src/main.rs:10:14
   |
10 | #[no_mangle] pub const RAH: usize = 5;
   |              ---------^^^^^^^^^^^^^^^^
   |              |
   |              help: try a static value: `pub static`
   |
   = note: `#[deny(no_mangle_const_items)]` on by default

@rustbot claim

[JonathanBrouwer]

@rustbot label -needs-triage +regression-from-stable-to-beta +A-diagnostics +A-attributes +T-compiler
Caused by #145085

[qidirbaev]

Are there any updates?

[JonathanBrouwer]

I'll make sure to implement the fix sometime in the next few days :)