[INFO] cloning repository https://github.com/AnswerWong/rustlings-solution
[INFO] running `Command { std: "git" "-c" "credential.helper=" "-c" "credential.helper=/workspace/cargo-home/bin/git-credential-null" "clone" "--bare" "https://github.com/AnswerWong/rustlings-solution" "/workspace/cache/git-repos/https%3A%2F%2Fgithub.com%2FAnswerWong%2Frustlings-solution", kill_on_drop: false }`
[INFO] [stderr] Cloning into bare repository '/workspace/cache/git-repos/https%3A%2F%2Fgithub.com%2FAnswerWong%2Frustlings-solution'...
[INFO] running `Command { std: "git" "rev-parse" "HEAD", kill_on_drop: false }`
[INFO] [stdout] 06879794d585b802ed4935f555486ce8f9d03fc3
[INFO] checking AnswerWong/rustlings-solution against master#c8a31b780d5415358566a20b94912620a3f27067 for pr-139493-1
[INFO] running `Command { std: "git" "clone" "/workspace/cache/git-repos/https%3A%2F%2Fgithub.com%2FAnswerWong%2Frustlings-solution" "/workspace/builds/worker-4-tc1/source", kill_on_drop: false }`
[INFO] [stderr] Cloning into '/workspace/builds/worker-4-tc1/source'...
[INFO] [stderr] done.
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[INFO] started tweaking git repo https://github.com/AnswerWong/rustlings-solution
[INFO] finished tweaking git repo https://github.com/AnswerWong/rustlings-solution
[INFO] tweaked toml for git repo https://github.com/AnswerWong/rustlings-solution written to /workspace/builds/worker-4-tc1/source/Cargo.toml
[INFO] validating manifest of git repo https://github.com/AnswerWong/rustlings-solution on toolchain c8a31b780d5415358566a20b94912620a3f27067
[INFO] running `Command { std: CARGO_HOME="/workspace/cargo-home" RUSTUP_HOME="/workspace/rustup-home" "/workspace/cargo-home/bin/cargo" "+c8a31b780d5415358566a20b94912620a3f27067" "metadata" "--manifest-path" "Cargo.toml" "--no-deps", kill_on_drop: false }`
[INFO] crate git repo https://github.com/AnswerWong/rustlings-solution 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" "+c8a31b780d5415358566a20b94912620a3f27067" "fetch" "--manifest-path" "Cargo.toml", kill_on_drop: false }`
[INFO] [stderr]     Blocking waiting for file lock on package cache
[INFO] [stderr]  Downloading crates ...
[INFO] [stderr]   Downloaded argh_shared v0.1.10
[INFO] [stderr]   Downloaded serde_derive v1.0.158
[INFO] [stderr]   Downloaded argh_derive v0.1.10
[INFO] [stderr]   Downloaded argh v0.1.10
[INFO] [stderr]   Downloaded net2 v0.2.38
[INFO] [stderr]   Downloaded serde v1.0.158
[INFO] running `Command { std: "docker" "create" "-v" "/var/lib/crater-agent-workspace/builds/worker-4-tc1/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-4-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:e90291280db7d1fac5b66fc6dad9f9662629e7365a55743daf9bdf73ebc4ea79" "/opt/rustwide/cargo-home/bin/cargo" "+c8a31b780d5415358566a20b94912620a3f27067" "metadata" "--no-deps" "--format-version=1", kill_on_drop: false }`
[INFO] [stdout] 25f5de1aac02105b873c084e1682f1b1156969034e8450dccd00632752ec9082
[INFO] running `Command { std: "docker" "start" "-a" "25f5de1aac02105b873c084e1682f1b1156969034e8450dccd00632752ec9082", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "inspect" "25f5de1aac02105b873c084e1682f1b1156969034e8450dccd00632752ec9082", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "25f5de1aac02105b873c084e1682f1b1156969034e8450dccd00632752ec9082", kill_on_drop: false }`
[INFO] [stdout] 25f5de1aac02105b873c084e1682f1b1156969034e8450dccd00632752ec9082
[INFO] running `Command { std: "docker" "create" "-v" "/var/lib/crater-agent-workspace/builds/worker-4-tc1/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-4-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:e90291280db7d1fac5b66fc6dad9f9662629e7365a55743daf9bdf73ebc4ea79" "/opt/rustwide/cargo-home/bin/cargo" "+c8a31b780d5415358566a20b94912620a3f27067" "check" "--frozen" "--all" "--all-targets" "--message-format=json", kill_on_drop: false }`
[INFO] [stdout] 3f532b650324d29568dd6f87b52a69acf72f2f04adf4636f20b3033619d4ed96
[INFO] running `Command { std: "docker" "start" "-a" "3f532b650324d29568dd6f87b52a69acf72f2f04adf4636f20b3033619d4ed96", kill_on_drop: false }`
[INFO] [stderr]    Compiling proc-macro2 v1.0.53
[INFO] [stderr]    Compiling libc v0.2.140
[INFO] [stderr]    Compiling unicode-ident v1.0.8
[INFO] [stderr]    Compiling quote v1.0.26
[INFO] [stderr]    Compiling serde_derive v1.0.158
[INFO] [stderr]    Compiling serde v1.0.158
[INFO] [stderr]     Checking aho-corasick v0.7.20
[INFO] [stderr]    Compiling num-traits v0.2.15
[INFO] [stderr]    Compiling syn v1.0.109
[INFO] [stderr]    Compiling serde_json v1.0.94
[INFO] [stdout] error[E0635]: unknown feature `proc_macro_span_shrink`
[INFO] [stdout]   --> /opt/rustwide/cargo-home/registry/src/index.crates.io-1949cf8c6b5b557f/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 slab v0.4.8
[INFO] [stderr]     Checking itoa v1.0.6
[INFO] [stderr]     Checking ryu v1.0.13
[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 1 previous error
[INFO] [stderr] warning: build failed, waiting for other jobs to finish...
[INFO] running `Command { std: "docker" "inspect" "3f532b650324d29568dd6f87b52a69acf72f2f04adf4636f20b3033619d4ed96", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "3f532b650324d29568dd6f87b52a69acf72f2f04adf4636f20b3033619d4ed96", kill_on_drop: false }`
[INFO] [stdout] 3f532b650324d29568dd6f87b52a69acf72f2f04adf4636f20b3033619d4ed96
