Re: [PATCH] rust: clarify the language unstable features in use

[kernel test robot <lkp@intel.com>]

Hi Miguel,

kernel test robot noticed the following build errors:

[auto build test ERROR on e6ea10d5dbe082c54add289b44f08c9fcfe658af]

url:    https://github.com/intel-lab-lkp/linux/commits/Miguel-Ojeda/rust-clarify-the-language-unstable-features-in-use/20250328-051650
base:   e6ea10d5dbe082c54add289b44f08c9fcfe658af
patch link:    https://lore.kernel.org/r/20250327211302.286313-1-ojeda%40kernel.org
patch subject: [PATCH] rust: clarify the language unstable features in use
config: x86_64-rhel-9.4-rust (https://download.01.org/0day-ci/archive/20250328/202503280805.Oq84ECdB-lkp@intel.com/config)
compiler: clang version 18.1.8 (https://github.com/llvm/llvm-project 3b5b5c1ec4a3095ab096dd780e84d7ab81f3d7ff)
rustc: rustc 1.78.0 (9b00956e5 2024-04-29)
reproduce (this is a W=1 build): (https://download.01.org/0day-ci/archive/20250328/202503280805.Oq84ECdB-lkp@intel.com/reproduce)

If you fix the issue in a separate patch/commit (i.e. not just a new version of
the same patch/commit), kindly add following tags
| Reported-by: kernel test robot <lkp@intel.com>
| Closes: https://lore.kernel.org/oe-kbuild-all/202503280805.Oq84ECdB-lkp@intel.com/

All errors (new ones prefixed by >>):

   PATH=/opt/cross/clang-18/bin:/usr/local/bin:/usr/sbin:/usr/bin:/sbin:/bin
   INFO PATH=/opt/cross/rustc-1.78.0-bindgen-0.65.1/cargo/bin:/opt/cross/clang-18/bin:/usr/local/bin:/usr/sbin:/usr/bin:/sbin:/bin
   /usr/bin/timeout -k 100 12h /usr/bin/make W=1 --keep-going LLVM=1 -j32 -C source O=/kbuild/obj/consumer/x86_64-rhel-9.4-rust ARCH=x86_64 SHELL=/bin/bash rustfmtcheck
   make: Entering directory '/kbuild/src/consumer'
   make[1]: Entering directory '/kbuild/obj/consumer/x86_64-rhel-9.4-rust'
>> Diff in rust/kernel/lib.rs at line 12:
    //! do so first instead of bypassing this crate.
    
    #![no_std]
   -
    // Please see https://github.com/Rust-for-Linux/linux/issues/2 for details on
    // the unstable features in use.
    
   Diff in rust/kernel/lib.rs at line 19:
    // Stable since Rust 1.79.0.
    #![feature(inline_const)]
   -
    // Stable since Rust 1.81.0.
    #![feature(lint_reasons)]
   -
    // Stable since Rust 1.82.0.
    #![feature(raw_ref_op)]
   -
    // Stable since Rust 1.83.0.
    #![feature(const_maybe_uninit_as_mut_ptr)]
    #![feature(const_mut_refs)]
   Diff in rust/kernel/lib.rs at line 31:
    #![feature(const_ptr_write)]
    #![feature(const_refs_to_cell)]
   -
    // Expected to become stable.
    #![feature(arbitrary_self_types)]
   -
    // `feature(derive_coerce_pointee)` is the one expected to become stable.
    #![cfg_attr(CONFIG_RUSTC_HAS_COERCE_POINTEE, feature(derive_coerce_pointee))]
    #![cfg_attr(not(CONFIG_RUSTC_HAS_COERCE_POINTEE), feature(coerce_unsized))]
   make[2]: *** [Makefile:1811: rustfmt] Error 123
   make[2]: Target 'rustfmtcheck' not remade because of errors.
   make[1]: Leaving directory '/kbuild/obj/consumer/x86_64-rhel-9.4-rust'
   make[1]: *** [Makefile:251: __sub-make] Error 2
   make[1]: Target 'rustfmtcheck' not remade because of errors.
   make: *** [Makefile:251: __sub-make] Error 2
   make: Target 'rustfmtcheck' not remade because of errors.
   make: Leaving directory '/kbuild/src/consumer'

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https://github.com/intel/lkp-tests/wiki