[INFO] updating cached repository https://github.com/Ibexian/char_predictor
[INFO] running `"git" "-c" "credential.helper=" "-c" "credential.helper=/workspace/cargo-home/bin/git-credential-null" "-c" "remote.origin.fetch=refs/heads/*:refs/heads/*" "fetch" "origin" "--force" "--prune"`
[INFO] running `"git" "rev-parse" "HEAD"`
[INFO] [stdout] 4a75007895fc1f57326754287a21332c038fdf0f
[INFO] testing Ibexian/char_predictor against 1.44.0 for beta-1.45-1
[INFO] running `"git" "clone" "/workspace/cache/git-repos/https%3A%2F%2Fgithub.com%2FIbexian%2Fchar_predictor" "/workspace/builds/worker-11/source"`
[INFO] [stderr] Cloning into '/workspace/builds/worker-11/source'...
[INFO] [stderr] done.
[INFO] validating manifest of git repo https://github.com/Ibexian/char_predictor on toolchain 1.44.0
[INFO] running `"/workspace/cargo-home/bin/cargo" "+1.44.0" "read-manifest" "--manifest-path" "Cargo.toml"`
[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-11/source/Cargo.toml
[INFO] crate git repo https://github.com/Ibexian/char_predictor already has a lockfile, it will not be regenerated
[INFO] running `"/workspace/cargo-home/bin/cargo" "+1.44.0" "fetch" "--locked" "--manifest-path" "Cargo.toml"`
[INFO] running `"docker" "create" "-v" "/var/lib/crater-agent-workspace/builds/worker-11/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-11/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" "MAP_USER_ID=0" "-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" "--network" "none" "rustops/crates-build-env" "/opt/rustwide/cargo-home/bin/cargo" "+1.44.0" "build" "--frozen"`
[INFO] [stderr] WARNING: Your kernel does not support swap limit capabilities or the cgroup is not mounted. Memory limited without swap.
[INFO] [stdout] b182c6cb72f266f64505c01d22a59a5d18f014cb0997a3d92586b8e70c85aea9
[INFO] running `"docker" "start" "-a" "b182c6cb72f266f64505c01d22a59a5d18f014cb0997a3d92586b8e70c85aea9"`
[INFO] [stderr] sudo: setrlimit(RLIMIT_CORE): Operation not permitted
[INFO] [stderr]     Blocking waiting for file lock on package cache
[INFO] [stderr]    Compiling cc v1.0.20
[INFO] [stderr]    Compiling pkg-config v0.3.13
[INFO] [stderr]    Compiling proc-macro2 v0.4.13
[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 itoa v0.4.2
[INFO] [stderr]    Compiling num-traits v0.2.5
[INFO] [stderr]    Compiling byteorder v1.2.4
[INFO] [stderr]    Compiling log v0.4.4
[INFO] [stderr]    Compiling filetime v0.2.1
[INFO] [stderr]    Compiling xattr v0.2.2
[INFO] [stderr]    Compiling socket2 v0.3.7
[INFO] [stderr]    Compiling aligned_alloc v0.1.3
[INFO] [stderr]    Compiling tar v0.4.16
[INFO] [stderr] error[E0554]: `#![feature]` may not be used on the stable release channel
[INFO] [stderr]   --> /opt/rustwide/cargo-home/registry/src/github.com-1ecc6299db9ec823/proc-macro2-0.4.13/src/lib.rs:49:5
[INFO] [stderr]    |
[INFO] [stderr] 49 |     feature(proc_macro_raw_ident, proc_macro_span)
[INFO] [stderr]    |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
[INFO] [stderr] 
[INFO] [stderr] error[E0658]: use of unstable library feature 'proc_macro_def_site'
[INFO] [stderr]    --> /opt/rustwide/cargo-home/registry/src/github.com-1ecc6299db9ec823/proc-macro2-0.4.13/src/unstable.rs:359:27
[INFO] [stderr]     |
[INFO] [stderr] 359 |             Span::Nightly(proc_macro::Span::def_site())
[INFO] [stderr]     |                           ^^^^^^^^^^^^^^^^^^^^^^^^^^
[INFO] [stderr]     |
[INFO] [stderr]     = note: see issue #54724 <https://github.com/rust-lang/rust/issues/54724> for more information
[INFO] [stderr] 
[INFO] [stderr] error: aborting due to 2 previous errors
[INFO] [stderr] 
[INFO] [stderr] Some errors have detailed explanations: E0554, E0658.
[INFO] [stderr] For more information about an error, try `rustc --explain E0554`.
[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 `"docker" "inspect" "b182c6cb72f266f64505c01d22a59a5d18f014cb0997a3d92586b8e70c85aea9"`
[INFO] running `"docker" "rm" "-f" "b182c6cb72f266f64505c01d22a59a5d18f014cb0997a3d92586b8e70c85aea9"`
[INFO] [stdout] b182c6cb72f266f64505c01d22a59a5d18f014cb0997a3d92586b8e70c85aea9