[INFO] fetching crate syndicate 0.44.0-rc.3...
[INFO] testing syndicate-0.44.0-rc.3 against 1.90.0 for beta-1.91-3
[INFO] extracting crate syndicate 0.44.0-rc.3 into /workspace/builds/worker-2-tc1/source
[INFO] started tweaking crates.io crate syndicate 0.44.0-rc.3
[INFO] removed 0 missing examples
[INFO] finished tweaking crates.io crate syndicate 0.44.0-rc.3
[INFO] tweaked toml for crates.io crate syndicate 0.44.0-rc.3 written to /workspace/builds/worker-2-tc1/source/Cargo.toml
[INFO] validating manifest of crates.io crate syndicate 0.44.0-rc.3 on toolchain 1.90.0
[INFO] running `Command { std: CARGO_HOME="/workspace/cargo-home" RUSTUP_HOME="/workspace/rustup-home" "/workspace/cargo-home/bin/cargo" "+1.90.0" "metadata" "--manifest-path" "Cargo.toml" "--no-deps", kill_on_drop: false }`
[INFO] crate crates.io crate syndicate 0.44.0-rc.3 already has a lockfile, it will not be regenerated
[INFO] running `Command { std: CARGO_HOME="/workspace/cargo-home" RUSTUP_HOME="/workspace/rustup-home" "/workspace/cargo-home/bin/cargo" "+1.90.0" "fetch" "--manifest-path" "Cargo.toml", kill_on_drop: false }`
[INFO] [stderr]     Updating crates.io index
[INFO] [stderr]  Downloading crates ...
[INFO] [stderr]   Downloaded tokio-util v0.6.10
[INFO] [stderr]   Downloaded syndicate-schema-plugin v0.12.0-rc.1
[INFO] [stderr]   Downloaded preserves-schema v6.0.0-rc.5
[INFO] [stderr]   Downloaded tokio v1.44.1
[INFO] [stderr]   Downloaded openssl-src v300.4.2+3.4.1
[INFO] [stderr]   Downloaded preserves v5.0.0-rc.6
[INFO] running `Command { std: "docker" "create" "-v" "/var/lib/crater-agent-workspace/builds/worker-2-tc1/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-2-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:e90291280db7d1fac5b66fc6dad9f9662629e7365a55743daf9bdf73ebc4ea79" "/opt/rustwide/cargo-home/bin/cargo" "+1.90.0" "metadata" "--no-deps" "--format-version=1", kill_on_drop: false }`
[INFO] [stdout] 6dc1980607e86e3f0559bb9d27c0840000675a1ac72f10275c9a7d5979fd0438
[INFO] running `Command { std: "docker" "start" "-a" "6dc1980607e86e3f0559bb9d27c0840000675a1ac72f10275c9a7d5979fd0438", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "inspect" "6dc1980607e86e3f0559bb9d27c0840000675a1ac72f10275c9a7d5979fd0438", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "6dc1980607e86e3f0559bb9d27c0840000675a1ac72f10275c9a7d5979fd0438", kill_on_drop: false }`
[INFO] [stdout] 6dc1980607e86e3f0559bb9d27c0840000675a1ac72f10275c9a7d5979fd0438
[INFO] running `Command { std: "docker" "create" "-v" "/var/lib/crater-agent-workspace/builds/worker-2-tc1/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-2-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=warn" "-e" "RUSTDOCFLAGS=--cap-lints=warn" "-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:e90291280db7d1fac5b66fc6dad9f9662629e7365a55743daf9bdf73ebc4ea79" "/opt/rustwide/cargo-home/bin/cargo" "+1.90.0" "build" "--frozen" "--message-format=json", kill_on_drop: false }`
[INFO] [stdout] e6de3429863c077ea637a9bd0862a206a53f415ad7a92fa7fb995d83c7a6dd5e
[INFO] running `Command { std: "docker" "start" "-a" "e6de3429863c077ea637a9bd0862a206a53f415ad7a92fa7fb995d83c7a6dd5e", kill_on_drop: false }`
[INFO] [stderr]    Compiling proc-macro2 v1.0.94
[INFO] [stderr]    Compiling unicode-width v0.1.14
[INFO] [stderr]    Compiling libc v0.2.171
[INFO] [stderr]    Compiling num-traits v0.2.19
[INFO] [stderr]    Compiling heck v0.3.3
[INFO] [stderr]    Compiling aho-corasick v1.1.3
[INFO] [stderr]    Compiling bytemuck v1.22.0
[INFO] [stderr]    Compiling once_cell v1.21.1
[INFO] [stderr]    Compiling convert_case v0.4.0
[INFO] [stderr]    Compiling serde v1.0.219
[INFO] [stderr]    Compiling smallvec v1.14.0
[INFO] [stderr]    Compiling log v0.4.26
[INFO] [stderr]    Compiling digest v0.10.7
[INFO] [stderr]    Compiling iana-time-zone v0.1.61
[INFO] [stderr]    Compiling tracing-core v0.1.33
[INFO] [stderr]    Compiling thread_local v1.1.8
[INFO] [stderr]    Compiling matchers v0.0.1
[INFO] [stderr]    Compiling blake2 v0.10.6
[INFO] [stderr]    Compiling textwrap v0.11.0
[INFO] [stderr]    Compiling hmac v0.12.1
[INFO] [stderr]    Compiling tracing-log v0.1.4
[INFO] [stderr]    Compiling num-integer v0.1.46
[INFO] [stderr]    Compiling chrono v0.4.40
[INFO] [stderr]    Compiling quote v1.0.40
[INFO] [stderr]    Compiling regex-automata v0.4.9
[INFO] [stderr]    Compiling syn v2.0.100
[INFO] [stderr]    Compiling syn v1.0.109
[INFO] [stderr]    Compiling atty v0.2.14
[INFO] [stderr]    Compiling parking_lot_core v0.9.10
[INFO] [stderr]    Compiling getrandom v0.2.15
[INFO] [stderr]    Compiling num-bigint v0.4.6
[INFO] [stderr]    Compiling proc-macro-error-attr v1.0.4
[INFO] [stderr]    Compiling clap v2.34.0
[INFO] [stderr]    Compiling parking_lot v0.12.3
[INFO] [stderr]    Compiling serde_json v1.0.140
[INFO] [stderr]    Compiling tracing-serde v0.1.3
[INFO] [stderr]    Compiling proc-macro-error v1.0.4
[INFO] [stderr]    Compiling structopt-derive v0.4.18
[INFO] [stderr]    Compiling regex v1.11.1
[INFO] [stderr]    Compiling preserves v5.0.0-rc.6
[INFO] [stderr]    Compiling structopt v0.3.26
[INFO] [stderr]    Compiling tracing-attributes v0.1.28
[INFO] [stderr]    Compiling futures-macro v0.3.31
[INFO] [stderr]    Compiling tokio-macros v2.5.0
[INFO] [stderr]    Compiling pin-project-internal v1.1.10
[INFO] [stderr]    Compiling preserves-schema v6.0.0-rc.5
[INFO] [stderr]    Compiling tokio v1.44.1
[INFO] [stderr]    Compiling futures-util v0.3.31
[INFO] [stderr]    Compiling pin-project v1.1.10
[INFO] [stderr]    Compiling tracing v0.1.41
[INFO] [stderr]    Compiling tracing-subscriber v0.2.25
[INFO] [stderr]    Compiling tracing-futures v0.2.5
[INFO] [stderr]    Compiling syndicate-schema-plugin v0.12.0-rc.1
[INFO] [stderr]    Compiling futures-executor v0.3.31
[INFO] [stderr]    Compiling futures v0.3.31
[INFO] [stderr]    Compiling tokio-util v0.6.10
[INFO] [stderr]    Compiling syndicate v0.44.0-rc.3 (/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(min_specialization)]
[INFO] [stdout]   | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] For more information about this error, try `rustc --explain E0554`.
[INFO] [stdout] 
[INFO] [stderr] error: could not compile `syndicate` (lib) due to 1 previous error
[INFO] running `Command { std: "docker" "inspect" "e6de3429863c077ea637a9bd0862a206a53f415ad7a92fa7fb995d83c7a6dd5e", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "e6de3429863c077ea637a9bd0862a206a53f415ad7a92fa7fb995d83c7a6dd5e", kill_on_drop: false }`
[INFO] [stdout] e6de3429863c077ea637a9bd0862a206a53f415ad7a92fa7fb995d83c7a6dd5e
