[INFO] fetching crate ark-ff-optimized 0.4.1...
[INFO] checking ark-ff-optimized-0.4.1 against 1.95.0 for pr-155915
[INFO] extracting crate ark-ff-optimized 0.4.1 into /workspace/builds/worker-5-tc1/source
[INFO] started tweaking crates.io crate ark-ff-optimized 0.4.1
[INFO] finished tweaking crates.io crate ark-ff-optimized 0.4.1
[INFO] tweaked toml for crates.io crate ark-ff-optimized 0.4.1 written to /workspace/builds/worker-5-tc1/source/Cargo.toml
[INFO] validating manifest of crates.io crate ark-ff-optimized 0.4.1 on toolchain 1.95.0
[INFO] running `Command { std: CARGO_HOME="/workspace/cargo-home" RUSTUP_HOME="/workspace/rustup-home" "/workspace/cargo-home/bin/cargo" "+1.95.0" "metadata" "--manifest-path" "Cargo.toml" "--no-deps", kill_on_drop: false }`
[INFO] running `Command { std: CARGO_HOME="/workspace/cargo-home" RUSTUP_HOME="/workspace/rustup-home" "/workspace/cargo-home/bin/cargo" "+1.95.0" "generate-lockfile" "--manifest-path" "Cargo.toml", kill_on_drop: false }`
[INFO] [stderr]     Blocking waiting for file lock on package cache
[INFO] [stderr]     Updating crates.io index
[INFO] [stderr]     Blocking waiting for file lock on package cache
[INFO] [stderr]      Locking 108 packages to latest compatible versions
[INFO] [stderr]       Adding ark-algebra-bench-templates v0.4.2 (available: v0.6.0)
[INFO] [stderr]       Adding ark-algebra-test-templates v0.4.2 (available: v0.6.0)
[INFO] [stderr]       Adding ark-ff v0.4.2 (available: v0.6.0)
[INFO] [stderr]       Adding ark-serialize v0.4.2 (available: v0.6.0)
[INFO] [stderr]       Adding ark-std v0.4.0 (available: v0.6.0)
[INFO] [stderr]       Adding generic-array v0.14.7 (available: v0.14.9)
[INFO] running `Command { std: CARGO_HOME="/workspace/cargo-home" RUSTUP_HOME="/workspace/rustup-home" "/workspace/cargo-home/bin/cargo" "+1.95.0" "fetch" "--manifest-path" "Cargo.toml", kill_on_drop: false }`
[INFO] [stderr]  Downloading crates ...
[INFO] [stderr]   Downloaded ark-algebra-test-templates v0.4.2
[INFO] [stderr]   Downloaded ark-algebra-bench-templates v0.4.2
[INFO] running `Command { std: "docker" "create" "-v" "/var/lib/crater-agent-workspace/builds/worker-5-tc1/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-5-tc1/source:/opt/rustwide/workdir:ro,Z" "-v" "/var/lib/crater-agent-workspace/cargo-home:/opt/rustwide/cargo-home:ro,Z" "-v" "/var/lib/crater-agent-workspace/rustup-home:/opt/rustwide/rustup-home:ro,Z" "-e" "SOURCE_DIR=/opt/rustwide/workdir" "-e" "CARGO_TARGET_DIR=/opt/rustwide/target" "-e" "CARGO_HOME=/opt/rustwide/cargo-home" "-e" "RUSTUP_HOME=/opt/rustwide/rustup-home" "-w" "/opt/rustwide/workdir" "-m" "1610612736" "--user" "0:0" "--network" "none" "ghcr.io/rust-lang/crates-build-env/linux@sha256:d429b63d4308055ea97f60fb1d3dfca48854a00942f1bd2ad806beaf015945ec" "/opt/rustwide/cargo-home/bin/cargo" "+1.95.0" "metadata" "--no-deps" "--format-version=1", kill_on_drop: false }`
[INFO] [stdout] 4b9a6abac417f6d23763c5574e96c69a5b06d8e976aa5262e75c25f596657753
[INFO] running `Command { std: "docker" "start" "-a" "4b9a6abac417f6d23763c5574e96c69a5b06d8e976aa5262e75c25f596657753", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "inspect" "4b9a6abac417f6d23763c5574e96c69a5b06d8e976aa5262e75c25f596657753", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "4b9a6abac417f6d23763c5574e96c69a5b06d8e976aa5262e75c25f596657753", kill_on_drop: false }`
[INFO] [stdout] 4b9a6abac417f6d23763c5574e96c69a5b06d8e976aa5262e75c25f596657753
[INFO] running `Command { std: "docker" "create" "-v" "/var/lib/crater-agent-workspace/builds/worker-5-tc1/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-5-tc1/source:/opt/rustwide/workdir:ro,Z" "-v" "/var/lib/crater-agent-workspace/cargo-home:/opt/rustwide/cargo-home:ro,Z" "-v" "/var/lib/crater-agent-workspace/rustup-home:/opt/rustwide/rustup-home:ro,Z" "-e" "SOURCE_DIR=/opt/rustwide/workdir" "-e" "CARGO_TARGET_DIR=/opt/rustwide/target" "-e" "CARGO_INCREMENTAL=0" "-e" "RUST_BACKTRACE=full" "-e" "RUSTFLAGS=--cap-lints=forbid" "-e" "RUSTDOCFLAGS=--cap-lints=forbid" "-e" "CARGO_HOME=/opt/rustwide/cargo-home" "-e" "RUSTUP_HOME=/opt/rustwide/rustup-home" "-w" "/opt/rustwide/workdir" "-m" "1610612736" "--user" "0:0" "--network" "none" "ghcr.io/rust-lang/crates-build-env/linux@sha256:d429b63d4308055ea97f60fb1d3dfca48854a00942f1bd2ad806beaf015945ec" "/opt/rustwide/cargo-home/bin/cargo" "+1.95.0" "check" "--frozen" "--all" "--all-targets" "--message-format=json", kill_on_drop: false }`
[INFO] [stdout] c47c0c0e304dd0b803f8d5a8735dad56e16087893a6faa93b594b2e72caaf59f
[INFO] running `Command { std: "docker" "start" "-a" "c47c0c0e304dd0b803f8d5a8735dad56e16087893a6faa93b594b2e72caaf59f", kill_on_drop: false }`
[INFO] [stderr]    Compiling syn v2.0.117
[INFO] [stderr]    Compiling syn v1.0.109
[INFO] [stderr]     Checking crypto-common v0.1.7
[INFO] [stderr]     Checking once_cell v1.21.4
[INFO] [stderr]    Compiling indexmap v1.9.3
[INFO] [stderr]    Compiling libc v0.2.186
[INFO] [stderr]     Checking serde_json v1.0.149
[INFO] [stderr]     Checking regex-syntax v0.8.10
[INFO] [stderr]     Checking digest v0.10.7
[INFO] [stderr]     Checking plotters v0.3.7
[INFO] [stderr]     Checking sha2 v0.10.9
[INFO] [stderr]     Checking clap v3.2.25
[INFO] [stderr]     Checking regex-automata v0.4.14
[INFO] [stderr]     Checking atty v0.2.14
[INFO] [stderr]     Checking regex v1.12.3
[INFO] [stderr]    Compiling ark-serialize-derive v0.4.2
[INFO] [stderr]    Compiling ark-ff-macros v0.4.2
[INFO] [stderr]    Compiling derivative v2.2.0
[INFO] [stderr]    Compiling ark-ff-asm v0.4.2
[INFO] [stderr]    Compiling zerocopy-derive v0.8.48
[INFO] [stderr]    Compiling zeroize_derive v1.4.3
[INFO] [stderr]    Compiling serde_derive v1.0.228
[INFO] [stderr]     Checking zeroize v1.8.2
[INFO] [stderr]     Checking zerocopy v0.8.48
[INFO] [stderr]     Checking serde v1.0.228
[INFO] [stderr]     Checking tinytemplate v1.2.1
[INFO] [stderr]     Checking ppv-lite86 v0.2.21
[INFO] [stderr]     Checking ahash v0.8.12
[INFO] [stderr]     Checking half v2.7.1
[INFO] [stderr]     Checking hashbrown v0.13.2
[INFO] [stderr]     Checking rand_chacha v0.3.1
[INFO] [stderr]     Checking ciborium-ll v0.2.2
[INFO] [stderr]     Checking ciborium v0.2.2
[INFO] [stderr]     Checking rand v0.8.6
[INFO] [stderr]     Checking criterion v0.4.0
[INFO] [stderr]     Checking ark-std v0.4.0
[INFO] [stderr]     Checking ark-serialize v0.4.2
[INFO] [stderr]     Checking ark-ff v0.4.2
[INFO] [stderr]     Checking ark-poly v0.4.2
[INFO] [stderr]     Checking ark-ff-optimized v0.4.1 (/opt/rustwide/workdir)
[INFO] [stdout] error[E0554]: `#![feature]` may not be used on the stable release channel
[INFO] [stdout]  --> src/lib.rs:2:1
[INFO] [stdout]   |
[INFO] [stdout] 2 | #![feature(const_mut_refs, const_trait_impl)]
[INFO] [stdout]   | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
[INFO] [stdout]   |
[INFO] [stdout]   = help: the feature `const_mut_refs` has been stable since `1.83.0` and no longer requires an attribute to enable
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: the feature `const_mut_refs` has been stable since 1.83.0 and no longer requires an attribute to enable
[INFO] [stdout]  --> src/lib.rs:2:12
[INFO] [stdout]   |
[INFO] [stdout] 2 | #![feature(const_mut_refs, const_trait_impl)]
[INFO] [stdout]   |            ^^^^^^^^^^^^^^
[INFO] [stdout]   |
[INFO] [stdout]   = note: `#[warn(stable_features)]` on by default
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: `#[must_use]` attribute cannot be used on trait methods in impl blocks
[INFO] [stdout]    --> src/fp31.rs:601:5
[INFO] [stdout]     |
[INFO] [stdout] 601 |     #[must_use]
[INFO] [stdout]     |     ^^^^^^^^^^^
[INFO] [stdout]     |
[INFO] [stdout]     = warning: this was previously accepted by the compiler but is being phased out; it will become a hard error in a future release!
[INFO] [stdout]     = help: `#[must_use]` can be applied to data types, foreign functions, functions, inherent methods, provided trait methods, required trait methods, and traits
[INFO] [stdout]     = note: `#[warn(unused_attributes)]` (part of `#[warn(unused)]`) on by default
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] For more information about this error, try `rustc --explain E0554`.
[INFO] [stdout] 
[INFO] [stderr] error: could not compile `ark-ff-optimized` (lib) due to 1 previous error; 2 warnings emitted
[INFO] [stderr] warning: build failed, waiting for other jobs to finish...
[INFO] running `Command { std: "docker" "inspect" "c47c0c0e304dd0b803f8d5a8735dad56e16087893a6faa93b594b2e72caaf59f", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "c47c0c0e304dd0b803f8d5a8735dad56e16087893a6faa93b594b2e72caaf59f", kill_on_drop: false }`
[INFO] [stdout] c47c0c0e304dd0b803f8d5a8735dad56e16087893a6faa93b594b2e72caaf59f
