[INFO] fetching crate zerogc-context 0.2.0-alpha.7...
[INFO] testing zerogc-context-0.2.0-alpha.7 against 1.91.0 for beta-1.92-2
[INFO] extracting crate zerogc-context 0.2.0-alpha.7 into /workspace/builds/worker-3-tc1/source
[INFO] started tweaking crates.io crate zerogc-context 0.2.0-alpha.7
[INFO] finished tweaking crates.io crate zerogc-context 0.2.0-alpha.7
[INFO] tweaked toml for crates.io crate zerogc-context 0.2.0-alpha.7 written to /workspace/builds/worker-3-tc1/source/Cargo.toml
[INFO] validating manifest of crates.io crate zerogc-context 0.2.0-alpha.7 on toolchain 1.91.0
[INFO] running `Command { std: CARGO_HOME="/workspace/cargo-home" RUSTUP_HOME="/workspace/rustup-home" "/workspace/cargo-home/bin/cargo" "+1.91.0" "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" "+1.91.0" "generate-lockfile" "--manifest-path" "Cargo.toml", kill_on_drop: false }`
[INFO] [stderr]     Updating crates.io index
[INFO] [stderr]      Locking 46 packages to latest compatible versions
[INFO] [stderr]       Adding parking_lot v0.11.2 (available: v0.12.5)
[INFO] running `Command { std: CARGO_HOME="/workspace/cargo-home" RUSTUP_HOME="/workspace/rustup-home" "/workspace/cargo-home/bin/cargo" "+1.91.0" "fetch" "--manifest-path" "Cargo.toml", kill_on_drop: false }`
[INFO] [stderr]  Downloading crates ...
[INFO] [stderr]   Downloaded darling_macro v0.13.4
[INFO] [stderr]   Downloaded darling_core v0.13.4
[INFO] [stderr]   Downloaded slog v2.8.2
[INFO] [stderr]   Downloaded inherent v1.0.13
[INFO] [stderr]   Downloaded darling v0.13.4
[INFO] [stderr]   Downloaded heck v0.3.3
[INFO] [stderr]   Downloaded proc-macro-kwargs-derive v0.1.5
[INFO] [stderr]   Downloaded proc-macro-kwargs v0.1.5
[INFO] [stderr]   Downloaded zerogc-derive v0.2.0-alpha.6
[INFO] [stderr]   Downloaded zerogc v0.2.0-alpha.7
[INFO] running `Command { std: "docker" "create" "-v" "/var/lib/crater-agent-workspace/builds/worker-3-tc1/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-3-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@sha256:4848fb76d95f26979359cc7e45710b1dbc8f3acb7aeedee7c460d7702230f228" "/opt/rustwide/cargo-home/bin/cargo" "+1.91.0" "metadata" "--no-deps" "--format-version=1", kill_on_drop: false }`
[INFO] [stdout] 1bb64c02ac347371885b460519e532d79cf1bcef5ee78668a0dfafef533c414b
[INFO] running `Command { std: "docker" "start" "-a" "1bb64c02ac347371885b460519e532d79cf1bcef5ee78668a0dfafef533c414b", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "inspect" "1bb64c02ac347371885b460519e532d79cf1bcef5ee78668a0dfafef533c414b", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "1bb64c02ac347371885b460519e532d79cf1bcef5ee78668a0dfafef533c414b", kill_on_drop: false }`
[INFO] [stdout] 1bb64c02ac347371885b460519e532d79cf1bcef5ee78668a0dfafef533c414b
[INFO] running `Command { std: "docker" "create" "-v" "/var/lib/crater-agent-workspace/builds/worker-3-tc1/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-3-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@sha256:4848fb76d95f26979359cc7e45710b1dbc8f3acb7aeedee7c460d7702230f228" "/opt/rustwide/cargo-home/bin/cargo" "+1.91.0" "build" "--frozen" "--message-format=json", kill_on_drop: false }`
[INFO] [stdout] 31c767f90719db1238833c7fecf3e5827e8d7602f1d411c77ba82d4cec84bd2f
[INFO] running `Command { std: "docker" "start" "-a" "31c767f90719db1238833c7fecf3e5827e8d7602f1d411c77ba82d4cec84bd2f", kill_on_drop: false }`
[INFO] [stderr]    Compiling syn v1.0.109
[INFO] [stderr]    Compiling indexmap v1.9.3
[INFO] [stderr]    Compiling strsim v0.10.0
[INFO] [stderr]    Compiling serde v1.0.228
[INFO] [stderr]    Compiling hashbrown v0.12.3
[INFO] [stderr]    Compiling scopeguard v1.2.0
[INFO] [stderr]    Compiling heck v0.3.3
[INFO] [stderr]    Compiling itertools v0.10.5
[INFO] [stderr]    Compiling instant v0.1.13
[INFO] [stderr]    Compiling inherent v1.0.13
[INFO] [stderr]    Compiling bumpalo v3.19.0
[INFO] [stderr]    Compiling slog v2.8.2
[INFO] [stderr]    Compiling parking_lot_core v0.8.6
[INFO] [stderr]    Compiling lock_api v0.4.14
[INFO] [stderr]    Compiling parking_lot v0.11.2
[INFO] [stderr]    Compiling erased-serde v0.3.31
[INFO] [stderr]    Compiling darling_core v0.13.4
[INFO] [stderr]    Compiling proc-macro-kwargs-derive v0.1.5
[INFO] [stderr]    Compiling proc-macro-kwargs v0.1.5
[INFO] [stdout] error[E0554]: `#![feature]` may not be used on the stable release channel
[INFO] [stdout]  --> /opt/rustwide/cargo-home/registry/src/index.crates.io-1949cf8c6b5b557f/proc-macro-kwargs-0.1.5/src/lib.rs:3:1
[INFO] [stdout]   |
[INFO] [stdout] 3 | #![feature(trait_alias)]
[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 `proc-macro-kwargs` (lib) due to 1 previous error
[INFO] [stderr] warning: build failed, waiting for other jobs to finish...
[INFO] running `Command { std: "docker" "inspect" "31c767f90719db1238833c7fecf3e5827e8d7602f1d411c77ba82d4cec84bd2f", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "31c767f90719db1238833c7fecf3e5827e8d7602f1d411c77ba82d4cec84bd2f", kill_on_drop: false }`
[INFO] [stdout] 31c767f90719db1238833c7fecf3e5827e8d7602f1d411c77ba82d4cec84bd2f