[INFO] cloning repository https://github.com/Ibexian/char_predictor
[INFO] running `Command { std: "git" "-c" "credential.helper=" "-c" "credential.helper=/workspace/cargo-home/bin/git-credential-null" "clone" "--bare" "https://github.com/Ibexian/char_predictor" "/workspace/cache/git-repos/https%3A%2F%2Fgithub.com%2FIbexian%2Fchar_predictor", kill_on_drop: false }`
[INFO] [stderr] Cloning into bare repository '/workspace/cache/git-repos/https%3A%2F%2Fgithub.com%2FIbexian%2Fchar_predictor'...
[INFO] running `Command { std: "git" "rev-parse" "HEAD", kill_on_drop: false }`
[INFO] [stdout] 4a75007895fc1f57326754287a21332c038fdf0f
[INFO] checking Ibexian/char_predictor against master#90442458ac46b1d5eed752c316da25450f67285b for pr-81477
[INFO] running `Command { std: "git" "clone" "/workspace/cache/git-repos/https%3A%2F%2Fgithub.com%2FIbexian%2Fchar_predictor" "/workspace/builds/worker-4/source", kill_on_drop: false }`
[INFO] [stderr] Cloning into '/workspace/builds/worker-4/source'...
[INFO] [stderr] done.
[INFO] validating manifest of git repo https://github.com/Ibexian/char_predictor on toolchain 90442458ac46b1d5eed752c316da25450f67285b
[INFO] running `Command { std: "/workspace/cargo-home/bin/cargo" "+90442458ac46b1d5eed752c316da25450f67285b" "metadata" "--manifest-path" "Cargo.toml" "--no-deps", kill_on_drop: false }`
[INFO] started tweaking git repo https://github.com/Ibexian/char_predictor
[INFO] finished tweaking git repo https://github.com/Ibexian/char_predictor
[INFO] tweaked toml for git repo https://github.com/Ibexian/char_predictor written to /workspace/builds/worker-4/source/Cargo.toml
[INFO] crate git repo https://github.com/Ibexian/char_predictor already has a lockfile, it will not be regenerated
[INFO] running `Command { std: "/workspace/cargo-home/bin/cargo" "+90442458ac46b1d5eed752c316da25450f67285b" "fetch" "--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-4/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-4/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" "+90442458ac46b1d5eed752c316da25450f67285b" "metadata" "--no-deps" "--format-version=1", kill_on_drop: false }`
[INFO] [stdout] b433b27af0a8c628e4ff252e860af4efd357daf1d30e7007d50736e479acd2fe
[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" "b433b27af0a8c628e4ff252e860af4efd357daf1d30e7007d50736e479acd2fe", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "inspect" "b433b27af0a8c628e4ff252e860af4efd357daf1d30e7007d50736e479acd2fe", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "b433b27af0a8c628e4ff252e860af4efd357daf1d30e7007d50736e479acd2fe", kill_on_drop: false }`
[INFO] [stdout] b433b27af0a8c628e4ff252e860af4efd357daf1d30e7007d50736e479acd2fe
[INFO] running `Command { std: "docker" "create" "-v" "/var/lib/crater-agent-workspace/builds/worker-4/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-4/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" "+90442458ac46b1d5eed752c316da25450f67285b" "check" "--frozen" "--all" "--all-targets" "--message-format=json", kill_on_drop: false }`
[INFO] [stdout] 3d0627ed4316b73f03cc989932d4db32476f3d046e50917ccc0430dc8ff9459b
[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" "3d0627ed4316b73f03cc989932d4db32476f3d046e50917ccc0430dc8ff9459b", kill_on_drop: false }`
[INFO] [stderr]    Compiling pkg-config v0.3.13
[INFO] [stderr]    Compiling proc-macro2 v0.4.13
[INFO] [stderr]    Compiling unicode-xid v0.1.0
[INFO] [stderr]    Compiling serde v1.0.74
[INFO] [stderr]    Compiling ryu v0.2.5
[INFO] [stderr]    Compiling wasm-bindgen-shared v0.2.17
[INFO] [stderr]    Compiling winapi-build v0.1.1
[INFO] [stderr]    Compiling openssl-probe v0.1.2
[INFO] [stderr]    Compiling itoa v0.4.2
[INFO] [stderr]    Compiling semver-parser v0.7.0
[INFO] [stderr]    Compiling build_const v0.2.1
[INFO] [stderr]    Compiling num-traits v0.2.5
[INFO] [stderr]     Checking winapi v0.2.8
[INFO] [stderr]     Checking byteorder v1.2.4
[INFO] [stderr]    Compiling miniz-sys v0.1.10
[INFO] [stderr]    Compiling xattr v0.2.2
[INFO] [stderr]    Compiling socket2 v0.3.7
[INFO] [stderr]    Compiling filetime v0.2.1
[INFO] [stderr]    Compiling log v0.4.4
[INFO] [stderr]    Compiling lazy_static v1.1.0
[INFO] [stderr]    Compiling semver v0.9.0
[INFO] [stderr]    Compiling crc v1.8.1
[INFO] [stderr]    Compiling kernel32-sys v0.2.2
[INFO] [stderr]    Compiling tar v0.4.16
[INFO] [stderr]    Compiling libz-sys v1.0.20
[INFO] [stderr]    Compiling openssl-sys v0.9.35
[INFO] [stderr]    Compiling curl-sys v0.4.8
[INFO] [stdout] error[E0658]: use of unstable library feature 'proc_macro_def_site'
[INFO] [stdout]    --> /opt/rustwide/cargo-home/registry/src/github.com-1ecc6299db9ec823/proc-macro2-0.4.13/src/unstable.rs:359:27
[INFO] [stdout]     |
[INFO] [stdout] 359 |             Span::Nightly(proc_macro::Span::def_site())
[INFO] [stdout]     |                           ^^^^^^^^^^^^^^^^^^^^^^^^^^
[INFO] [stdout]     |
[INFO] [stdout]     = note: see issue #54724 <https://github.com/rust-lang/rust/issues/54724> for more information
[INFO] [stdout]     = help: add `#![feature(proc_macro_def_site)]` to the crate attributes to enable
[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 E0658`.
[INFO] [stdout] 
[INFO] [stderr] error: could not compile `proc-macro2`
[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" "3d0627ed4316b73f03cc989932d4db32476f3d046e50917ccc0430dc8ff9459b", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "3d0627ed4316b73f03cc989932d4db32476f3d046e50917ccc0430dc8ff9459b", kill_on_drop: false }`
[INFO] [stdout] 3d0627ed4316b73f03cc989932d4db32476f3d046e50917ccc0430dc8ff9459b