[INFO] fetching crate racer 2.1.42...
[INFO] testing racer-2.1.42 against 1.49.0 for beta-1.50-1
[INFO] extracting crate racer 2.1.42 into /workspace/builds/worker-2/source
[INFO] validating manifest of crates.io crate racer 2.1.42 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 crates.io crate racer 2.1.42
[INFO] finished tweaking crates.io crate racer 2.1.42
[INFO] tweaked toml for crates.io crate racer 2.1.42 written to /workspace/builds/worker-2/source/Cargo.toml
[INFO] crate crates.io crate racer 2.1.42 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] [stderr]     Blocking waiting for file lock on package cache
[INFO] running `Command { std: "docker" "create" "-v" "/var/lib/crater-agent-workspace/builds/worker-2/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-2/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:c8ac004eab7d63a0ad09a2dde3d3353ba464f767bee4de425dc8f74c46a1905e" "/opt/rustwide/cargo-home/bin/cargo" "+1.49.0" "metadata" "--no-deps" "--format-version=1", kill_on_drop: false }`
[INFO] [stdout] d66b63071fbd5c760e67c05a121bc0959495afdc9f5aacf51607da0898ff77ac
[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" "d66b63071fbd5c760e67c05a121bc0959495afdc9f5aacf51607da0898ff77ac", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "inspect" "d66b63071fbd5c760e67c05a121bc0959495afdc9f5aacf51607da0898ff77ac", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "d66b63071fbd5c760e67c05a121bc0959495afdc9f5aacf51607da0898ff77ac", kill_on_drop: false }`
[INFO] [stdout] d66b63071fbd5c760e67c05a121bc0959495afdc9f5aacf51607da0898ff77ac
[INFO] running `Command { std: "docker" "create" "-v" "/var/lib/crater-agent-workspace/builds/worker-2/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-2/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:c8ac004eab7d63a0ad09a2dde3d3353ba464f767bee4de425dc8f74c46a1905e" "/opt/rustwide/cargo-home/bin/cargo" "+1.49.0" "build" "--frozen" "--message-format=json", kill_on_drop: false }`
[INFO] [stdout] 864d51265163cf6fbe2c15d47ac14ac0389728439d061a7ffce07c8660410bb8
[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" "864d51265163cf6fbe2c15d47ac14ac0389728439d061a7ffce07c8660410bb8", kill_on_drop: false }`
[INFO] [stderr]    Compiling autocfg v1.0.0
[INFO] [stderr]    Compiling libc v0.2.77
[INFO] [stderr]    Compiling proc-macro2 v1.0.10
[INFO] [stderr]    Compiling syn v1.0.17
[INFO] [stderr]    Compiling smallvec v1.4.2
[INFO] [stderr]    Compiling getrandom v0.1.14
[INFO] [stderr]    Compiling cc v1.0.53
[INFO] [stderr]    Compiling rustc-rayon-core v0.3.0
[INFO] [stderr]    Compiling ppv-lite86 v0.2.6
[INFO] [stderr]    Compiling either v1.5.3
[INFO] [stderr]    Compiling arrayvec v0.5.1
[INFO] [stderr]    Compiling stable_deref_trait v1.1.1
[INFO] [stderr]    Compiling rustc-ap-rustc_graphviz v697.0.0
[INFO] [stderr]    Compiling scoped-tls v1.0.0
[INFO] [stdout] error[E0554]: `#![feature]` may not be used on the stable release channel
[INFO] [stdout]   --> /opt/rustwide/cargo-home/registry/src/github.com-1ecc6299db9ec823/smallvec-1.4.2/src/lib.rs:74:32
[INFO] [stdout]    |
[INFO] [stdout] 74 | #![cfg_attr(feature = "union", feature(untagged_unions))]
[INFO] [stdout]    |                                ^^^^^^^^^^^^^^^^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] error[E0554]: `#![feature]` may not be used on the stable release channel
[INFO] [stdout]   --> /opt/rustwide/cargo-home/registry/src/github.com-1ecc6299db9ec823/smallvec-1.4.2/src/lib.rs:77:37
[INFO] [stdout]    |
[INFO] [stdout] 77 | #![cfg_attr(feature = "may_dangle", feature(dropck_eyepatch))]
[INFO] [stdout]    |                                     ^^^^^^^^^^^^^^^^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] error[E0554]: `#![feature]` may not be used on the stable release channel
[INFO] [stdout]    --> /opt/rustwide/cargo-home/registry/src/github.com-1ecc6299db9ec823/rustc-ap-rustc_graphviz-697.0.0/src/lib.rs:278:1
[INFO] [stdout]     |
[INFO] [stdout] 278 | #![feature(nll)]
[INFO] [stdout]     | ^^^^^^^^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] error: aborting due to previous error
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] For more information about this error, try `rustc --explain E0554`.
[INFO] [stdout] 
[INFO] [stderr] error: could not compile `rustc-ap-rustc_graphviz`
[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] [stdout] error: aborting due to 2 previous errors
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] For more information about this error, try `rustc --explain E0554`.
[INFO] [stdout] 
[INFO] [stderr] error: build failed
[INFO] running `Command { std: "docker" "inspect" "864d51265163cf6fbe2c15d47ac14ac0389728439d061a7ffce07c8660410bb8", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "864d51265163cf6fbe2c15d47ac14ac0389728439d061a7ffce07c8660410bb8", kill_on_drop: false }`
[INFO] [stdout] 864d51265163cf6fbe2c15d47ac14ac0389728439d061a7ffce07c8660410bb8