[INFO] fetching crate json_derive 0.0.1-alpha1...
[INFO] checking json_derive-0.0.1-alpha1 against try#7b3565da729099dbe807466fcd118fb2815986e0 for pr-81789
[INFO] extracting crate json_derive 0.0.1-alpha1 into /workspace/builds/worker-6/source
[INFO] validating manifest of crates.io crate json_derive 0.0.1-alpha1 on toolchain 7b3565da729099dbe807466fcd118fb2815986e0
[INFO] running `Command { std: "/workspace/cargo-home/bin/cargo" "+7b3565da729099dbe807466fcd118fb2815986e0" "metadata" "--manifest-path" "Cargo.toml" "--no-deps", kill_on_drop: false }`
[INFO] started tweaking crates.io crate json_derive 0.0.1-alpha1
[INFO] finished tweaking crates.io crate json_derive 0.0.1-alpha1
[INFO] tweaked toml for crates.io crate json_derive 0.0.1-alpha1 written to /workspace/builds/worker-6/source/Cargo.toml
[INFO] running `Command { std: "/workspace/cargo-home/bin/cargo" "+7b3565da729099dbe807466fcd118fb2815986e0" "generate-lockfile" "--manifest-path" "Cargo.toml" "-Zno-index-update", kill_on_drop: false }`
[INFO] running `Command { std: "/workspace/cargo-home/bin/cargo" "+7b3565da729099dbe807466fcd118fb2815986e0" "fetch" "--locked" "--manifest-path" "Cargo.toml", kill_on_drop: false }`
[INFO] [stderr]     Blocking waiting for file lock on package cache
[INFO] [stderr]  Downloading crates ...
[INFO] [stderr]   Downloaded syn v0.15.31
[INFO] running `Command { std: "docker" "create" "-v" "/var/lib/crater-agent-workspace/builds/worker-6/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-6/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@sha256:20528e8c29e4536546f0102ce88568b16ea7538393a33fcca951030f7af10457" "/opt/rustwide/cargo-home/bin/cargo" "+7b3565da729099dbe807466fcd118fb2815986e0" "metadata" "--no-deps" "--format-version=1", kill_on_drop: false }`
[INFO] [stdout] c18f22590192b564db08a84751264c3b859b7d0afdf7a0090b883d9ee6a56dfb
[INFO] [stderr] WARNING: Your kernel does not support swap limit capabilities or the cgroup is not mounted. Memory limited without swap.
[INFO] running `Command { std: "docker" "start" "-a" "c18f22590192b564db08a84751264c3b859b7d0afdf7a0090b883d9ee6a56dfb", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "inspect" "c18f22590192b564db08a84751264c3b859b7d0afdf7a0090b883d9ee6a56dfb", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "c18f22590192b564db08a84751264c3b859b7d0afdf7a0090b883d9ee6a56dfb", kill_on_drop: false }`
[INFO] [stdout] c18f22590192b564db08a84751264c3b859b7d0afdf7a0090b883d9ee6a56dfb
[INFO] running `Command { std: "docker" "create" "-v" "/var/lib/crater-agent-workspace/builds/worker-6/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-6/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" "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@sha256:20528e8c29e4536546f0102ce88568b16ea7538393a33fcca951030f7af10457" "/opt/rustwide/cargo-home/bin/cargo" "+7b3565da729099dbe807466fcd118fb2815986e0" "check" "--frozen" "--all" "--all-targets" "--message-format=json", kill_on_drop: false }`
[INFO] [stderr] WARNING: Your kernel does not support swap limit capabilities or the cgroup is not mounted. Memory limited without swap.
[INFO] [stdout] b20c97efe3bee3b3077c0d4b663ef047c9cc5d4ec3bf02bedfc7bef86c79c9d9
[INFO] running `Command { std: "docker" "start" "-a" "b20c97efe3bee3b3077c0d4b663ef047c9cc5d4ec3bf02bedfc7bef86c79c9d9", kill_on_drop: false }`
[INFO] [stderr]    Compiling serde v1.0.89
[INFO] [stderr]    Compiling syn v0.15.31
[INFO] [stderr]    Compiling indexmap v1.6.2
[INFO] [stderr]     Checking quote v0.6.11
[INFO] [stderr]     Checking serde_json v1.0.39
[INFO] [stderr]     Checking json_derive v0.0.1-alpha1 (/opt/rustwide/workdir)
[INFO] [stdout] warning: unused extern crate
[INFO] [stdout]  --> src/lib.rs:5:1
[INFO] [stdout]   |
[INFO] [stdout] 5 | extern crate proc_macro;
[INFO] [stdout]   | ^^^^^^^^^^^^^^^^^^^^^^^^ help: remove it
[INFO] [stdout]   |
[INFO] [stdout] note: the lint level is defined here
[INFO] [stdout]  --> src/lib.rs:3:9
[INFO] [stdout]   |
[INFO] [stdout] 3 | #![warn(unused_extern_crates)]
[INFO] [stdout]   |         ^^^^^^^^^^^^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused extern crate
[INFO] [stdout]  --> src/lib.rs:5:1
[INFO] [stdout]   |
[INFO] [stdout] 5 | extern crate proc_macro;
[INFO] [stdout]   | ^^^^^^^^^^^^^^^^^^^^^^^^ help: remove it
[INFO] [stdout]   |
[INFO] [stdout] note: the lint level is defined here
[INFO] [stdout]  --> src/lib.rs:3:9
[INFO] [stdout]   |
[INFO] [stdout] 3 | #![warn(unused_extern_crates)]
[INFO] [stdout]   |         ^^^^^^^^^^^^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: 1 warning emitted
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: 1 warning emitted
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stderr]     Finished dev [unoptimized + debuginfo] target(s) in 10.10s
[INFO] running `Command { std: "docker" "inspect" "b20c97efe3bee3b3077c0d4b663ef047c9cc5d4ec3bf02bedfc7bef86c79c9d9", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "b20c97efe3bee3b3077c0d4b663ef047c9cc5d4ec3bf02bedfc7bef86c79c9d9", kill_on_drop: false }`
[INFO] [stdout] b20c97efe3bee3b3077c0d4b663ef047c9cc5d4ec3bf02bedfc7bef86c79c9d9