build-std compilation fails depending on custom target's file name when compiling wasm32 with target-feature atomics

[Kyykek]

Problem

Cargo fails to compile custom target with build-std (std, panic_abort) depending on the file name of the json target spec (see steps below). Source code.
The target.json files used for this were copies of the wasm32-unknown-unknown target spec with added "features": "+atomics,+bulk-memory". The problem also persists when using rustflags.

Steps

(All steps are with build-std in the config.toml file and target-feature being set one way or another)

compare target files

diff target.json wasm32-target.json

<no output>

wasm-target.json

cargo +nightly build --target=wasm32-target.json

Finished dev [unoptimized + debuginfo] target(s) in 0.05s

target.json

cargo +nightly build --target=target.json

error: `futex_condvar::Condvar::new` is not yet stable as a const fn
   --> [HOME_DIR]/.rustup/toolchains/nightly-x86_64-unknown-linux-gnu/lib/rustlib/src/rust/library/std/src/sync/condvar.rs:127:26
    |
127 |         Condvar { inner: sys::Condvar::new() }
    |                          ^^^^^^^^^^^^^^^^^^^

error: `futex_mutex::Mutex::new` is not yet stable as a const fn
   --> [HOME_DIR]/.rustup/toolchains/nightly-x86_64-unknown-linux-gnu/lib/rustlib/src/rust/library/std/src/sync/mutex.rs:230:24
    |
230 |         Mutex { inner: sys::Mutex::new(), poison: poison::Flag::new(), data: UnsafeCell::new(t) }
    |                        ^^^^^^^^^^^^^^^^^

error: `sys_common::once::futex::Once::new` is not yet stable as a const fn
  --> [HOME_DIR]/.rustup/toolchains/nightly-x86_64-unknown-linux-gnu/lib/rustlib/src/rust/library/std/src/sync/once.rs:76:23
   |
76 |         Once { inner: sys::Once::new() }
   |                       ^^^^^^^^^^^^^^^^

error: `futex_rwlock::RwLock::new` is not yet stable as a const fn
   --> [HOME_DIR]/.rustup/toolchains/nightly-x86_64-unknown-linux-gnu/lib/rustlib/src/rust/library/std/src/sync/rwlock.rs:161:25
    |
161 |         RwLock { inner: sys::RwLock::new(), poison: poison::Flag::new(), data: UnsafeCell::new(t) }
    |                         ^^^^^^^^^^^^^^^^^^

Possible Solution(s)

No response

Notes

Tested with a few nightly versions of the last week.

Version

cargo 1.76.0-nightly (71cd3a926 2023-11-20)
release: 1.76.0-nightly
commit-hash: 71cd3a926f0cf41eeaf9f2a7f2194b2aff85b0f6
commit-date: 2023-11-20
host: x86_64-unknown-linux-gnu
libgit2: 1.7.1 (sys:0.18.1 vendored)
libcurl: 8.4.0-DEV (sys:0.4.68+curl-8.4.0 vendored ssl:OpenSSL/1.1.1u)
ssl: OpenSSL 1.1.1u  30 May 2023
os: Debian 12 (bookworm) [64-bit]

[ehuss]

Thanks for the report! This is a known issue tracked in rust-lang/rust#104761. You'll need to mirror a related target name for now.

[Kyykek]

Thanks for the report! This is a known issue tracked in rust-lang/rust#104761. You'll need to mirror a related target name for now.

Thank you very much! I expected this to be the case but couldn't find it anywhere :D