[INFO] cloning repository https://github.com/alexxtcs42/rustlings
[INFO] running `Command { std: "git" "-c" "credential.helper=" "-c" "credential.helper=/workspace/cargo-home/bin/git-credential-null" "clone" "--bare" "https://github.com/alexxtcs42/rustlings" "/workspace/cache/git-repos/https%3A%2F%2Fgithub.com%2Falexxtcs42%2Frustlings", kill_on_drop: false }`
[INFO] [stderr] Cloning into bare repository '/workspace/cache/git-repos/https%3A%2F%2Fgithub.com%2Falexxtcs42%2Frustlings'...
[INFO] running `Command { std: "git" "rev-parse" "HEAD", kill_on_drop: false }`
[INFO] [stdout] a8a0081db01cdcc01c960f5baf66e642b412fbd1
[INFO] checking alexxtcs42/rustlings/a8a0081db01cdcc01c960f5baf66e642b412fbd1 against master#a42d94ebb883116f2867cbe3016d9bde9ca6d3f7 for pr-117593
[INFO] running `Command { std: "git" "clone" "/workspace/cache/git-repos/https%3A%2F%2Fgithub.com%2Falexxtcs42%2Frustlings" "/workspace/builds/worker-5-tc1/source", kill_on_drop: false }`
[INFO] [stderr] Cloning into '/workspace/builds/worker-5-tc1/source'...
[INFO] [stderr] done.
[INFO] validating manifest of git repo https://github.com/alexxtcs42/rustlings on toolchain a42d94ebb883116f2867cbe3016d9bde9ca6d3f7
[INFO] running `Command { std: CARGO_HOME="/workspace/cargo-home" RUSTUP_HOME="/workspace/rustup-home" "/workspace/cargo-home/bin/cargo" "+a42d94ebb883116f2867cbe3016d9bde9ca6d3f7" "metadata" "--manifest-path" "Cargo.toml" "--no-deps", kill_on_drop: false }`
[INFO] started tweaking git repo https://github.com/alexxtcs42/rustlings
[INFO] finished tweaking git repo https://github.com/alexxtcs42/rustlings
[INFO] tweaked toml for git repo https://github.com/alexxtcs42/rustlings written to /workspace/builds/worker-5-tc1/source/Cargo.toml
[INFO] crate git repo https://github.com/alexxtcs42/rustlings already has a lockfile, it will not be regenerated
[INFO] running `Command { std: CARGO_HOME="/workspace/cargo-home" RUSTUP_HOME="/workspace/rustup-home" "/workspace/cargo-home/bin/cargo" "+a42d94ebb883116f2867cbe3016d9bde9ca6d3f7" "fetch" "--manifest-path" "Cargo.toml", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "create" "-v" "/var/lib/crater-agent-workspace/builds/worker-5-tc1/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-5-tc1/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@sha256:0c7e0e8312ad82a1bed3696438480b7da990d348377d3754e1cd95b06a8a36c7" "/opt/rustwide/cargo-home/bin/cargo" "+a42d94ebb883116f2867cbe3016d9bde9ca6d3f7" "metadata" "--no-deps" "--format-version=1", kill_on_drop: false }`
[INFO] [stdout] a55c53e5f21cf96903ee2d945c19573e737198bbc36d84c0ace05639678a5ac4
[INFO] running `Command { std: "docker" "start" "-a" "a55c53e5f21cf96903ee2d945c19573e737198bbc36d84c0ace05639678a5ac4", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "inspect" "a55c53e5f21cf96903ee2d945c19573e737198bbc36d84c0ace05639678a5ac4", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "a55c53e5f21cf96903ee2d945c19573e737198bbc36d84c0ace05639678a5ac4", kill_on_drop: false }`
[INFO] [stdout] a55c53e5f21cf96903ee2d945c19573e737198bbc36d84c0ace05639678a5ac4
[INFO] running `Command { std: "docker" "create" "-v" "/var/lib/crater-agent-workspace/builds/worker-5-tc1/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-5-tc1/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" "RUSTDOCFLAGS=--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@sha256:0c7e0e8312ad82a1bed3696438480b7da990d348377d3754e1cd95b06a8a36c7" "/opt/rustwide/cargo-home/bin/cargo" "+a42d94ebb883116f2867cbe3016d9bde9ca6d3f7" "check" "--frozen" "--all" "--all-targets" "--message-format=json", kill_on_drop: false }`
[INFO] [stdout] 51e62e853707beb2fc7f3d3c467966f667c16ed75576b525d9deb7cf07e205e9
[INFO] running `Command { std: "docker" "start" "-a" "51e62e853707beb2fc7f3d3c467966f667c16ed75576b525d9deb7cf07e205e9", kill_on_drop: false }`
[INFO] [stderr]    Compiling proc-macro2 v1.0.53
[INFO] [stderr]    Compiling quote v1.0.26
[INFO] [stderr]    Compiling unicode-ident v1.0.8
[INFO] [stderr]    Compiling libc v0.2.140
[INFO] [stderr]    Compiling memchr v2.5.0
[INFO] [stderr]    Compiling serde_derive v1.0.158
[INFO] [stderr]    Compiling log v0.4.17
[INFO] [stderr]    Compiling serde v1.0.158
[INFO] [stderr]    Compiling slab v0.4.8
[INFO] [stderr]    Compiling num-traits v0.2.15
[INFO] [stderr]    Compiling syn v1.0.109
[INFO] [stderr]    Compiling serde_json v1.0.94
[INFO] [stderr]     Checking regex-syntax v0.6.29
[INFO] [stdout] error[E0635]: unknown feature `proc_macro_span_shrink`
[INFO] [stdout]   --> /opt/rustwide/cargo-home/registry/src/index.crates.io-6f17d22bba15001f/proc-macro2-1.0.53/src/lib.rs:92:30
[INFO] [stdout]    |
[INFO] [stdout] 92 |     feature(proc_macro_span, proc_macro_span_shrink)
[INFO] [stdout]    |                              ^^^^^^^^^^^^^^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stderr]     Checking ryu v1.0.13
[INFO] [stdout] error: aborting due to previous error
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] For more information about this error, try `rustc --explain E0635`.
[INFO] [stdout] 
[INFO] [stderr] error: could not compile `proc-macro2` (lib) due to 2 previous errors
[INFO] [stderr] warning: build failed, waiting for other jobs to finish...
[INFO] running `Command { std: "docker" "inspect" "51e62e853707beb2fc7f3d3c467966f667c16ed75576b525d9deb7cf07e205e9", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "51e62e853707beb2fc7f3d3c467966f667c16ed75576b525d9deb7cf07e205e9", kill_on_drop: false }`
[INFO] [stdout] 51e62e853707beb2fc7f3d3c467966f667c16ed75576b525d9deb7cf07e205e9