[INFO] fetching crate cowrc 0.0.4...
[INFO] testing cowrc-0.0.4 against 1.54.0 for beta-1.55-1
[INFO] extracting crate cowrc 0.0.4 into /workspace/builds/worker-63/source
[INFO] validating manifest of crates.io crate cowrc 0.0.4 on toolchain 1.54.0
[INFO] running `Command { std: "/workspace/cargo-home/bin/cargo" "+1.54.0" "metadata" "--manifest-path" "Cargo.toml" "--no-deps", kill_on_drop: false }`
[INFO] started tweaking crates.io crate cowrc 0.0.4
[INFO] finished tweaking crates.io crate cowrc 0.0.4
[INFO] tweaked toml for crates.io crate cowrc 0.0.4 written to /workspace/builds/worker-63/source/Cargo.toml
[INFO] running `Command { std: "/workspace/cargo-home/bin/cargo" "+1.54.0" "generate-lockfile" "--manifest-path" "Cargo.toml" "-Zno-index-update", kill_on_drop: false }`
[INFO] running `Command { std: "/workspace/cargo-home/bin/cargo" "+1.54.0" "fetch" "--manifest-path" "Cargo.toml", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "create" "-v" "/var/lib/crater-agent-workspace/builds/worker-63/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-63/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@sha256:34b6a614d2c27851fe6cbf88fbd1137609cefab8b10d0615aaeb6fd47975d74e" "/opt/rustwide/cargo-home/bin/cargo" "+1.54.0" "metadata" "--no-deps" "--format-version=1", kill_on_drop: false }`
[INFO] [stdout] aa766c2a596399ac38f1b9cb603c5087493e640921be975253f41d52453f9183
[INFO] running `Command { std: "docker" "start" "-a" "aa766c2a596399ac38f1b9cb603c5087493e640921be975253f41d52453f9183", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "inspect" "aa766c2a596399ac38f1b9cb603c5087493e640921be975253f41d52453f9183", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "aa766c2a596399ac38f1b9cb603c5087493e640921be975253f41d52453f9183", kill_on_drop: false }`
[INFO] [stdout] aa766c2a596399ac38f1b9cb603c5087493e640921be975253f41d52453f9183
[INFO] running `Command { std: "docker" "create" "-v" "/var/lib/crater-agent-workspace/builds/worker-63/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-63/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" "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@sha256:34b6a614d2c27851fe6cbf88fbd1137609cefab8b10d0615aaeb6fd47975d74e" "/opt/rustwide/cargo-home/bin/cargo" "+1.54.0" "build" "--frozen" "--message-format=json", kill_on_drop: false }`
[INFO] [stdout] 211f35a9344b712df3033b55bc87f97a58ece333be02ae22b992ea56f0aae798
[INFO] running `Command { std: "docker" "start" "-a" "211f35a9344b712df3033b55bc87f97a58ece333be02ae22b992ea56f0aae798", kill_on_drop: false }`
[INFO] [stderr]     Blocking waiting for file lock on package cache
[INFO] [stderr]    Compiling cowrc v0.0.4 (/opt/rustwide/workdir)
[INFO] [stdout] error[E0554]: `#![feature]` may not be used on the stable release channel
[INFO] [stdout]  --> src/lib.rs:1:1
[INFO] [stdout]   |
[INFO] [stdout] 1 | #![feature(alloc)]
[INFO] [stdout]   | ^^^^^^^^^^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] error[E0599]: no method named `make_unique` found for struct `Rc<T>` in the current scope
[INFO] [stdout]   --> src/lib.rs:42:16
[INFO] [stdout]    |
[INFO] [stdout] 42 |         self.v.make_unique()
[INFO] [stdout]    |                ^^^^^^^^^^^ method not found in `Rc<T>`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] error[E0599]: no method named `make_unique` found for struct `Arc<T>` in the current scope
[INFO] [stdout]   --> src/lib.rs:55:16
[INFO] [stdout]    |
[INFO] [stdout] 55 |         self.v.make_unique()
[INFO] [stdout]    |                ^^^^^^^^^^^ method not found in `Arc<T>`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] error: aborting due to 3 previous errors
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] Some errors have detailed explanations: E0554, E0599.
[INFO] [stdout] 
[INFO] [stdout] For more information about an error, try `rustc --explain E0554`.
[INFO] [stdout] 
[INFO] [stderr] error: could not compile `cowrc`
[INFO] [stderr] 
[INFO] [stderr] To learn more, run the command again with --verbose.
[INFO] running `Command { std: "docker" "inspect" "211f35a9344b712df3033b55bc87f97a58ece333be02ae22b992ea56f0aae798", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "211f35a9344b712df3033b55bc87f97a58ece333be02ae22b992ea56f0aae798", kill_on_drop: false }`
[INFO] [stdout] 211f35a9344b712df3033b55bc87f97a58ece333be02ae22b992ea56f0aae798
