#![cfg_attr(..., feature)]` not respected

[bjorn3]

Summary

See title

Reproducer

I tried this code:

#![cfg_attr(not(cg_gcc), feature(intrinsics))]

#[cfg(not(cg_gcc))]
extern "rust-intrinsic" {
    fn copy_nonoverlapping<T>(src: &T, dst: &mut T, count: usize);
}

Does the code make use of any (1.49) nightly feature ?

• Nightly

Godbolt link

No response

Actual behavior

<source>:17:1: error: intrinsics are subject to change. add `#![feature(intrinsics)]` to the crate attributes to enable. [E0658]
   17 | extern "rust-intrinsic" {
      | ^~~~~~

Expected behavior

It compiles

GCC Version

gccrs (Compiler-Explorer-Build-gcc--binutils-2.44) 15.2.0