[INFO] cloning repository https://github.com/pLesur/serde_slim
[INFO] running `Command { std: "git" "-c" "credential.helper=" "-c" "credential.helper=/workspace/cargo-home/bin/git-credential-null" "clone" "--bare" "https://github.com/pLesur/serde_slim" "/workspace/cache/git-repos/https%3A%2F%2Fgithub.com%2FpLesur%2Fserde_slim", kill_on_drop: false }`
[INFO] [stderr] Cloning into bare repository '/workspace/cache/git-repos/https%3A%2F%2Fgithub.com%2FpLesur%2Fserde_slim'...
[INFO] running `Command { std: "git" "rev-parse" "HEAD", kill_on_drop: false }`
[INFO] [stdout] 29d809a58494f4d9286112074392f77f50e3c7d3
[INFO] testing pLesur/serde_slim against 1.49.0 for beta-1.50-1
[INFO] running `Command { std: "git" "clone" "/workspace/cache/git-repos/https%3A%2F%2Fgithub.com%2FpLesur%2Fserde_slim" "/workspace/builds/worker-12/source", kill_on_drop: false }`
[INFO] [stderr] Cloning into '/workspace/builds/worker-12/source'...
[INFO] [stderr] done.
[INFO] validating manifest of git repo https://github.com/pLesur/serde_slim on toolchain 1.49.0
[INFO] running `Command { std: "/workspace/cargo-home/bin/cargo" "+1.49.0" "read-manifest" "--manifest-path" "Cargo.toml", kill_on_drop: false }`
[INFO] started tweaking git repo https://github.com/pLesur/serde_slim
[INFO] finished tweaking git repo https://github.com/pLesur/serde_slim
[INFO] tweaked toml for git repo https://github.com/pLesur/serde_slim written to /workspace/builds/worker-12/source/Cargo.toml
[INFO] crate git repo https://github.com/pLesur/serde_slim already has a lockfile, it will not be regenerated
[INFO] running `Command { std: "/workspace/cargo-home/bin/cargo" "+1.49.0" "fetch" "--locked" "--manifest-path" "Cargo.toml", kill_on_drop: false }`
[INFO] [stderr]     Blocking waiting for file lock on package cache
[INFO] running `Command { std: "docker" "create" "-v" "/var/lib/crater-agent-workspace/builds/worker-12/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-12/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" "rustops/crates-build-env@sha256:b8eeb62f26c39b23691079a6cb6de528d8e88b4d71a8f6b1d30f8ba7d9c16de9" "/opt/rustwide/cargo-home/bin/cargo" "+1.49.0" "metadata" "--no-deps" "--format-version=1", 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] aeef6227edc24d76cb2591aa7278ac59d85e65b74021c51f3184a1fe9b6b574e
[INFO] running `Command { std: "docker" "start" "-a" "aeef6227edc24d76cb2591aa7278ac59d85e65b74021c51f3184a1fe9b6b574e", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "inspect" "aeef6227edc24d76cb2591aa7278ac59d85e65b74021c51f3184a1fe9b6b574e", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "aeef6227edc24d76cb2591aa7278ac59d85e65b74021c51f3184a1fe9b6b574e", kill_on_drop: false }`
[INFO] [stdout] aeef6227edc24d76cb2591aa7278ac59d85e65b74021c51f3184a1fe9b6b574e
[INFO] running `Command { std: "docker" "create" "-v" "/var/lib/crater-agent-workspace/builds/worker-12/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-12/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" "rustops/crates-build-env@sha256:b8eeb62f26c39b23691079a6cb6de528d8e88b4d71a8f6b1d30f8ba7d9c16de9" "/opt/rustwide/cargo-home/bin/cargo" "+1.49.0" "build" "--frozen" "--message-format=json", kill_on_drop: false }`
[INFO] [stdout] 78147f7dd6ce09781a80f8fb6ae5caf2353199461981d5cf6c32374b990b3685
[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" "78147f7dd6ce09781a80f8fb6ae5caf2353199461981d5cf6c32374b990b3685", kill_on_drop: false }`
[INFO] [stderr]    Compiling syn v0.15.42
[INFO] [stderr]    Compiling serde_slim v0.1.0 (/opt/rustwide/workdir)
[INFO] [stderr]     Finished dev [unoptimized + debuginfo] target(s) in 17.26s
[INFO] running `Command { std: "docker" "inspect" "78147f7dd6ce09781a80f8fb6ae5caf2353199461981d5cf6c32374b990b3685", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "78147f7dd6ce09781a80f8fb6ae5caf2353199461981d5cf6c32374b990b3685", kill_on_drop: false }`
[INFO] [stdout] 78147f7dd6ce09781a80f8fb6ae5caf2353199461981d5cf6c32374b990b3685
[INFO] running `Command { std: "docker" "create" "-v" "/var/lib/crater-agent-workspace/builds/worker-12/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-12/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" "rustops/crates-build-env@sha256:b8eeb62f26c39b23691079a6cb6de528d8e88b4d71a8f6b1d30f8ba7d9c16de9" "/opt/rustwide/cargo-home/bin/cargo" "+1.49.0" "test" "--frozen" "--no-run" "--message-format=json", kill_on_drop: false }`
[INFO] [stdout] a88d2663adb290d193c479c5a7d89601026008cad3004d1305355f02af6bf586
[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" "a88d2663adb290d193c479c5a7d89601026008cad3004d1305355f02af6bf586", kill_on_drop: false }`
[INFO] [stderr]    Compiling serde_slim v0.1.0 (/opt/rustwide/workdir)
[INFO] [stdout] error[E0557]: feature has been removed
[INFO] [stdout]  --> tests/basic.rs:1:12
[INFO] [stdout]   |
[INFO] [stdout] 1 | #![feature(custom_attribute)]
[INFO] [stdout]   |            ^^^^^^^^^^^^^^^^ feature has been removed
[INFO] [stdout]   |
[INFO] [stdout]   = note: removed in favor of `#![register_tool]` and `#![register_attr]`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] error: cannot find attribute `serde` in this scope
[INFO] [stdout]  --> tests/basic.rs:9:11
[INFO] [stdout]   |
[INFO] [stdout] 9 |         #[serde(skip_serializing)]
[INFO] [stdout]   |           ^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] error[E0554]: `#![feature]` may not be used on the stable release channel
[INFO] [stdout]  --> tests/basic.rs:1:1
[INFO] [stdout]   |
[INFO] [stdout] 1 | #![feature(custom_attribute)]
[INFO] [stdout]   | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
[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, E0557.
[INFO] [stdout] 
[INFO] [stdout] For more information about an error, try `rustc --explain E0554`.
[INFO] [stdout] 
[INFO] [stderr] error: could not compile `serde_slim`
[INFO] [stderr] 
[INFO] [stderr] To learn more, run the command again with --verbose.
[INFO] [stderr] warning: build failed, waiting for other jobs to finish...
[INFO] [stderr] error: build failed
[INFO] running `Command { std: "docker" "inspect" "a88d2663adb290d193c479c5a7d89601026008cad3004d1305355f02af6bf586", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "a88d2663adb290d193c479c5a7d89601026008cad3004d1305355f02af6bf586", kill_on_drop: false }`
[INFO] [stdout] a88d2663adb290d193c479c5a7d89601026008cad3004d1305355f02af6bf586