[INFO] cloning repository https://github.com/zhaihj/rust-play-ground
[INFO] running `Command { std: "git" "-c" "credential.helper=" "-c" "credential.helper=/workspace/cargo-home/bin/git-credential-null" "clone" "--bare" "https://github.com/zhaihj/rust-play-ground" "/workspace/cache/git-repos/https%3A%2F%2Fgithub.com%2Fzhaihj%2Frust-play-ground", kill_on_drop: false }`
[INFO] [stderr] Cloning into bare repository '/workspace/cache/git-repos/https%3A%2F%2Fgithub.com%2Fzhaihj%2Frust-play-ground'...
[INFO] running `Command { std: "git" "rev-parse" "HEAD", kill_on_drop: false }`
[INFO] [stdout] 7518e53f966e8c30644755ca289ee59c1d0e0a21
[INFO] checking zhaihj/rust-play-ground against master#568f6a8641e391ffcdcdb03e79d0901731d8d399 for pr-117164
[INFO] running `Command { std: "git" "clone" "/workspace/cache/git-repos/https%3A%2F%2Fgithub.com%2Fzhaihj%2Frust-play-ground" "/workspace/builds/worker-7-tc1/source", kill_on_drop: false }`
[INFO] [stderr] Cloning into '/workspace/builds/worker-7-tc1/source'...
[INFO] [stderr] done.
[INFO] validating manifest of git repo https://github.com/zhaihj/rust-play-ground on toolchain 568f6a8641e391ffcdcdb03e79d0901731d8d399
[INFO] running `Command { std: CARGO_HOME="/workspace/cargo-home" RUSTUP_HOME="/workspace/rustup-home" "/workspace/cargo-home/bin/cargo" "+568f6a8641e391ffcdcdb03e79d0901731d8d399" "metadata" "--manifest-path" "Cargo.toml" "--no-deps", kill_on_drop: false }`
[INFO] started tweaking git repo https://github.com/zhaihj/rust-play-ground
[INFO] finished tweaking git repo https://github.com/zhaihj/rust-play-ground
[INFO] tweaked toml for git repo https://github.com/zhaihj/rust-play-ground written to /workspace/builds/worker-7-tc1/source/Cargo.toml
[INFO] crate git repo https://github.com/zhaihj/rust-play-ground 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" "+568f6a8641e391ffcdcdb03e79d0901731d8d399" "fetch" "--manifest-path" "Cargo.toml", kill_on_drop: false }`
[INFO] [stderr]     Blocking waiting for file lock on package cache
[ERROR] error running command: no output for 300 seconds
[ERROR] this task or one of its parent failed!
[ERROR] no output for 300 seconds
[ERROR] note: run with `RUST_BACKTRACE=1` to display a backtrace.
[INFO] checking zhaihj/rust-play-ground against try#eb3956d47f58f1c7c0a5694b1d3401945bc41dce for pr-117164
[INFO] running `Command { std: "git" "clone" "/workspace/cache/git-repos/https%3A%2F%2Fgithub.com%2Fzhaihj%2Frust-play-ground" "/workspace/builds/worker-7-tc2/source", kill_on_drop: false }`
[INFO] [stderr] Cloning into '/workspace/builds/worker-7-tc2/source'...
[INFO] [stderr] done.
[INFO] validating manifest of git repo https://github.com/zhaihj/rust-play-ground on toolchain eb3956d47f58f1c7c0a5694b1d3401945bc41dce
[INFO] running `Command { std: CARGO_HOME="/workspace/cargo-home" RUSTUP_HOME="/workspace/rustup-home" "/workspace/cargo-home/bin/cargo" "+eb3956d47f58f1c7c0a5694b1d3401945bc41dce" "metadata" "--manifest-path" "Cargo.toml" "--no-deps", kill_on_drop: false }`
[INFO] started tweaking git repo https://github.com/zhaihj/rust-play-ground
[INFO] finished tweaking git repo https://github.com/zhaihj/rust-play-ground
[INFO] tweaked toml for git repo https://github.com/zhaihj/rust-play-ground written to /workspace/builds/worker-7-tc2/source/Cargo.toml
[INFO] crate git repo https://github.com/zhaihj/rust-play-ground 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" "+eb3956d47f58f1c7c0a5694b1d3401945bc41dce" "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] [stderr]  Downloading crates ...
[INFO] [stderr]   Downloaded libc v0.2.19
[INFO] running `Command { std: "docker" "create" "-v" "/var/lib/crater-agent-workspace/builds/worker-7-tc2/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-7-tc2/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@sha256:2788e3201cd34a07e3172128adcd8b3090168a8e3bcc40d7c032b9dda1df7d1c" "/opt/rustwide/cargo-home/bin/cargo" "+eb3956d47f58f1c7c0a5694b1d3401945bc41dce" "metadata" "--no-deps" "--format-version=1", kill_on_drop: false }`
[INFO] [stdout] 90410951fcdd67440bd41df3203d12fe1beeaafe1e788cd8594765805a01784f
[INFO] running `Command { std: "docker" "start" "-a" "90410951fcdd67440bd41df3203d12fe1beeaafe1e788cd8594765805a01784f", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "inspect" "90410951fcdd67440bd41df3203d12fe1beeaafe1e788cd8594765805a01784f", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "90410951fcdd67440bd41df3203d12fe1beeaafe1e788cd8594765805a01784f", kill_on_drop: false }`
[INFO] [stdout] 90410951fcdd67440bd41df3203d12fe1beeaafe1e788cd8594765805a01784f
[INFO] running `Command { std: "docker" "create" "-v" "/var/lib/crater-agent-workspace/builds/worker-7-tc2/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-7-tc2/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@sha256:2788e3201cd34a07e3172128adcd8b3090168a8e3bcc40d7c032b9dda1df7d1c" "/opt/rustwide/cargo-home/bin/cargo" "+eb3956d47f58f1c7c0a5694b1d3401945bc41dce" "check" "--frozen" "--all" "--all-targets" "--message-format=json", kill_on_drop: false }`
[INFO] [stdout] 4526449ecc52e3e106dd3ac44b0b941f038b942e3ca3a394d95cd03eaca67630
[INFO] running `Command { std: "docker" "start" "-a" "4526449ecc52e3e106dd3ac44b0b941f038b942e3ca3a394d95cd03eaca67630", kill_on_drop: false }`
[INFO] [stderr]     Checking libc v0.2.19
[INFO] [stderr]     Checking byteorder v1.0.0
[INFO] [stderr]     Checking memchr v1.0.1
[INFO] [stderr]     Checking csv v0.15.0
[INFO] [stderr]     Checking csv-read-test v0.1.0 (/opt/rustwide/workdir)
[INFO] [stdout] warning: unused `Result` that must be used
[INFO] [stdout]  --> src/bin/read-csv-matrix.rs:8:5
[INFO] [stdout]   |
[INFO] [stdout] 8 |     f.read_to_string(&mut s);
[INFO] [stdout]   |     ^^^^^^^^^^^^^^^^^^^^^^^^
[INFO] [stdout]   |
[INFO] [stdout]   = note: this `Result` may be an `Err` variant, which should be handled
[INFO] [stdout]   = note: `#[warn(unused_must_use)]` on by default
[INFO] [stdout] help: use `let _ = ...` to ignore the resulting value
[INFO] [stdout]   |
[INFO] [stdout] 8 |     let _ = f.read_to_string(&mut s);
[INFO] [stdout]   |     +++++++
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: 1 warning emitted
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused `Result` that must be used
[INFO] [stdout]  --> src/bin/read-csv-matrix.rs:8:5
[INFO] [stdout]   |
[INFO] [stdout] 8 |     f.read_to_string(&mut s);
[INFO] [stdout]   |     ^^^^^^^^^^^^^^^^^^^^^^^^
[INFO] [stdout]   |
[INFO] [stdout]   = note: this `Result` may be an `Err` variant, which should be handled
[INFO] [stdout]   = note: `#[warn(unused_must_use)]` on by default
[INFO] [stdout] help: use `let _ = ...` to ignore the resulting value
[INFO] [stdout]   |
[INFO] [stdout] 8 |     let _ = f.read_to_string(&mut s);
[INFO] [stdout]   |     +++++++
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: 1 warning emitted
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stderr]     Finished dev [unoptimized + debuginfo] target(s) in 0.83s
[INFO] [stderr] warning: the following packages contain code that will be rejected by a future version of Rust: rustc-serialize v0.3.22
[INFO] [stderr] note: to see what the problems were, use the option `--future-incompat-report`, or run `cargo report future-incompatibilities --id 2`
[INFO] running `Command { std: "docker" "inspect" "4526449ecc52e3e106dd3ac44b0b941f038b942e3ca3a394d95cd03eaca67630", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "4526449ecc52e3e106dd3ac44b0b941f038b942e3ca3a394d95cd03eaca67630", kill_on_drop: false }`
[INFO] [stdout] 4526449ecc52e3e106dd3ac44b0b941f038b942e3ca3a394d95cd03eaca67630