[INFO] cloning repository https://github.com/racer-rust/racer
[INFO] running `Command { std: "git" "-c" "credential.helper=" "-c" "credential.helper=/workspace/cargo-home/bin/git-credential-null" "clone" "--bare" "https://github.com/racer-rust/racer" "/workspace/cache/git-repos/https%3A%2F%2Fgithub.com%2Fracer-rust%2Fracer", kill_on_drop: false }`
[INFO] [stderr] Cloning into bare repository '/workspace/cache/git-repos/https%3A%2F%2Fgithub.com%2Fracer-rust%2Fracer'...
[INFO] running `Command { std: "git" "rev-parse" "HEAD", kill_on_drop: false }`
[INFO] [stdout] 48ed93d31dc0beea6fc7185e8496faa7fa9ded5c
[INFO] testing racer-rust/racer against 1.55.0 for beta-1.56-1
[INFO] running `Command { std: "git" "clone" "/workspace/cache/git-repos/https%3A%2F%2Fgithub.com%2Fracer-rust%2Fracer" "/workspace/builds/worker-79/source", kill_on_drop: false }`
[INFO] [stderr] Cloning into '/workspace/builds/worker-79/source'...
[INFO] [stderr] done.
[INFO] validating manifest of git repo https://github.com/racer-rust/racer on toolchain 1.55.0
[INFO] running `Command { std: "/workspace/cargo-home/bin/cargo" "+1.55.0" "metadata" "--manifest-path" "Cargo.toml" "--no-deps", kill_on_drop: false }`
[INFO] removed /workspace/builds/worker-79/source/rust-toolchain.toml
[INFO] started tweaking git repo https://github.com/racer-rust/racer
[INFO] finished tweaking git repo https://github.com/racer-rust/racer
[INFO] tweaked toml for git repo https://github.com/racer-rust/racer written to /workspace/builds/worker-79/source/Cargo.toml
[INFO] crate git repo https://github.com/racer-rust/racer already has a lockfile, it will not be regenerated
[INFO] running `Command { std: "/workspace/cargo-home/bin/cargo" "+1.55.0" "fetch" "--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-79/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-79/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:a89201d6b5b9fd45c15d5952ece0a0129e7e80cb26ec023fd59cf09bc26f1604" "/opt/rustwide/cargo-home/bin/cargo" "+1.55.0" "metadata" "--no-deps" "--format-version=1", kill_on_drop: false }`
[INFO] [stdout] 0037a2c11551d53530a133458cbb7357ca18e5da5cdbc29f97daddb31c9765c8
[INFO] running `Command { std: "docker" "start" "-a" "0037a2c11551d53530a133458cbb7357ca18e5da5cdbc29f97daddb31c9765c8", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "inspect" "0037a2c11551d53530a133458cbb7357ca18e5da5cdbc29f97daddb31c9765c8", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "0037a2c11551d53530a133458cbb7357ca18e5da5cdbc29f97daddb31c9765c8", kill_on_drop: false }`
[INFO] [stdout] 0037a2c11551d53530a133458cbb7357ca18e5da5cdbc29f97daddb31c9765c8
[INFO] running `Command { std: "docker" "create" "-v" "/var/lib/crater-agent-workspace/builds/worker-79/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-79/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:a89201d6b5b9fd45c15d5952ece0a0129e7e80cb26ec023fd59cf09bc26f1604" "/opt/rustwide/cargo-home/bin/cargo" "+1.55.0" "build" "--frozen" "--message-format=json", kill_on_drop: false }`
[INFO] [stdout] 3023795a28fad1ebe3f1893aae9b5db87e4abe33dadd527c1ef3a797f07befdd
[INFO] running `Command { std: "docker" "start" "-a" "3023795a28fad1ebe3f1893aae9b5db87e4abe33dadd527c1ef3a797f07befdd", kill_on_drop: false }`
[INFO] [stderr]    Compiling autocfg v1.0.0
[INFO] [stderr]    Compiling libc v0.2.77
[INFO] [stderr]    Compiling unicode-xid v0.2.0
[INFO] [stderr]    Compiling proc-macro2 v1.0.10
[INFO] [stderr]    Compiling syn v1.0.17
[INFO] [stderr]    Compiling getrandom v0.2.2
[INFO] [stderr]    Compiling cc v1.0.53
[INFO] [stderr]    Compiling typenum v1.12.0
[INFO] [stderr]    Compiling smallvec v1.6.1
[INFO] [stderr]    Compiling log v0.4.8
[INFO] [stderr]    Compiling rustc-rayon-core v0.3.1
[INFO] [stderr]    Compiling either v1.5.3
[INFO] [stderr]    Compiling unicode-width v0.1.7
[INFO] [stderr]    Compiling remove_dir_all v0.5.2
[INFO] [stderr]    Compiling arrayvec v0.7.0
[INFO] [stderr]    Compiling rustc-ap-rustc_graphviz v722.0.0
[INFO] [stderr]    Compiling serde v1.0.105
[INFO] [stderr]    Compiling termcolor v1.1.0
[INFO] [stderr]    Compiling ryu v1.0.3
[INFO] [stderr]    Compiling annotate-snippets v0.8.0
[INFO] [stderr]    Compiling rustc-ap-rustc_fs_util v722.0.0
[INFO] [stderr]    Compiling regex-syntax v0.6.17
[INFO] [stderr]    Compiling itoa v0.4.5
[INFO] [stderr]    Compiling vec_map v0.8.1
[INFO] [stderr]    Compiling humantime v2.0.0
[INFO] [stderr]    Compiling maybe-uninit v2.0.0
[INFO] [stderr]    Compiling generic-array v0.14.4
[INFO] [stderr]    Compiling instant v0.1.7
[INFO] [stderr]    Compiling lock_api v0.4.4
[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-722.0.0/src/lib.rs:278:1
[INFO] [stdout]     |
[INFO] [stdout] 278 | #![feature(nll)]
[INFO] [stdout]     | ^^^^^^^^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stderr]    Compiling tracing-core v0.1.15
[INFO] [stderr]    Compiling rustc-ap-rustc_lexer v722.0.0
[INFO] [stdout] error: aborting due to previous error
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stderr]    Compiling memchr v2.3.3
[INFO] [stdout] For more information about this error, try `rustc --explain E0554`.
[INFO] [stdout] 
[INFO] [stderr]    Compiling thread_local v1.0.1
[INFO] [stderr]    Compiling humantime v1.3.0
[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-1.6.1/src/lib.rs:76:37
[INFO] [stdout]    |
[INFO] [stdout] 76 | #![cfg_attr(feature = "may_dangle", feature(dropck_eyepatch))]
[INFO] [stdout]    |                                     ^^^^^^^^^^^^^^^^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stderr]    Compiling getopts v0.2.21
[INFO] [stderr]    Compiling textwrap v0.11.0
[INFO] [stderr] error: could not compile `rustc-ap-rustc_graphviz` due to 2 previous errors
[INFO] [stderr] warning: build failed, waiting for other jobs to finish...
[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: build failed
[INFO] running `Command { std: "docker" "inspect" "3023795a28fad1ebe3f1893aae9b5db87e4abe33dadd527c1ef3a797f07befdd", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "3023795a28fad1ebe3f1893aae9b5db87e4abe33dadd527c1ef3a797f07befdd", kill_on_drop: false }`
[INFO] [stdout] 3023795a28fad1ebe3f1893aae9b5db87e4abe33dadd527c1ef3a797f07befdd