[INFO] cloning repository https://github.com/GrayStrider/playground-rust-book
[INFO] running `Command { std: "git" "-c" "credential.helper=" "-c" "credential.helper=/workspace/cargo-home/bin/git-credential-null" "clone" "--bare" "https://github.com/GrayStrider/playground-rust-book" "/workspace/cache/git-repos/https%3A%2F%2Fgithub.com%2FGrayStrider%2Fplayground-rust-book", kill_on_drop: false }`
[INFO] [stderr] Cloning into bare repository '/workspace/cache/git-repos/https%3A%2F%2Fgithub.com%2FGrayStrider%2Fplayground-rust-book'...
[INFO] running `Command { std: "git" "rev-parse" "HEAD", kill_on_drop: false }`
[INFO] [stdout] bd341c23ce48da1b2611c5ee517e5a95c5bc8a50
[INFO] checking GrayStrider/playground-rust-book against master#8007b506ac5da629f223b755f5a5391edd5f6d01 for pr-88041
[INFO] running `Command { std: "git" "clone" "/workspace/cache/git-repos/https%3A%2F%2Fgithub.com%2FGrayStrider%2Fplayground-rust-book" "/workspace/builds/worker-88/source", kill_on_drop: false }`
[INFO] [stderr] Cloning into '/workspace/builds/worker-88/source'...
[INFO] [stderr] done.
[INFO] validating manifest of git repo https://github.com/GrayStrider/playground-rust-book on toolchain 8007b506ac5da629f223b755f5a5391edd5f6d01
[INFO] running `Command { std: "/workspace/cargo-home/bin/cargo" "+8007b506ac5da629f223b755f5a5391edd5f6d01" "metadata" "--manifest-path" "Cargo.toml" "--no-deps", kill_on_drop: false }`
[INFO] started tweaking git repo https://github.com/GrayStrider/playground-rust-book
[INFO] finished tweaking git repo https://github.com/GrayStrider/playground-rust-book
[INFO] tweaked toml for git repo https://github.com/GrayStrider/playground-rust-book written to /workspace/builds/worker-88/source/Cargo.toml
[INFO] crate git repo https://github.com/GrayStrider/playground-rust-book already has a lockfile, it will not be regenerated
[INFO] running `Command { std: "/workspace/cargo-home/bin/cargo" "+8007b506ac5da629f223b755f5a5391edd5f6d01" "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] running `Command { std: "docker" "create" "-v" "/var/lib/crater-agent-workspace/builds/worker-88/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-88/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@sha256:34b6a614d2c27851fe6cbf88fbd1137609cefab8b10d0615aaeb6fd47975d74e" "/opt/rustwide/cargo-home/bin/cargo" "+8007b506ac5da629f223b755f5a5391edd5f6d01" "metadata" "--no-deps" "--format-version=1", kill_on_drop: false }`
[INFO] [stdout] 07a0dc5589a06fee618b56651ae99c6ddbe076ed1022a3e17b480e9fb39d95a0
[INFO] running `Command { std: "docker" "start" "-a" "07a0dc5589a06fee618b56651ae99c6ddbe076ed1022a3e17b480e9fb39d95a0", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "inspect" "07a0dc5589a06fee618b56651ae99c6ddbe076ed1022a3e17b480e9fb39d95a0", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "07a0dc5589a06fee618b56651ae99c6ddbe076ed1022a3e17b480e9fb39d95a0", kill_on_drop: false }`
[INFO] [stdout] 07a0dc5589a06fee618b56651ae99c6ddbe076ed1022a3e17b480e9fb39d95a0
[INFO] running `Command { std: "docker" "create" "-v" "/var/lib/crater-agent-workspace/builds/worker-88/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-88/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@sha256:34b6a614d2c27851fe6cbf88fbd1137609cefab8b10d0615aaeb6fd47975d74e" "/opt/rustwide/cargo-home/bin/cargo" "+8007b506ac5da629f223b755f5a5391edd5f6d01" "check" "--frozen" "--all" "--all-targets" "--message-format=json", kill_on_drop: false }`
[INFO] [stdout] 04551db3f26392b9fd43c938d708a4c9a9b0c68714cc839e82f174d8cd595dc3
[INFO] running `Command { std: "docker" "start" "-a" "04551db3f26392b9fd43c938d708a4c9a9b0c68714cc839e82f174d8cd595dc3", kill_on_drop: false }`
[INFO] [stderr]    Compiling autocfg v1.0.1
[INFO] [stderr]     Checking pipeline v0.5.0
[INFO] [stderr]    Compiling num-traits v0.2.12
[INFO] [stderr]    Compiling num-integer v0.1.43
[INFO] [stderr]    Compiling num-bigint v0.3.0
[INFO] [stderr]    Compiling num-rational v0.3.0
[INFO] [stderr]    Compiling num-iter v0.1.41
[INFO] [stderr]     Checking num-complex v0.3.0
[INFO] [stderr]     Checking num v0.3.0
[INFO] [stderr]     Checking play3 v0.1.0 (/opt/rustwide/workdir)
[INFO] [stdout] warning: unused borrow that must be used
[INFO] [stdout]   --> src/std/vectors_arrays.rs:26:2
[INFO] [stdout]    |
[INFO] [stdout] 26 |     &v[2];
[INFO] [stdout]    |     ^^^^^ the borrow produces a value
[INFO] [stdout]    |
[INFO] [stdout]    = note: `#[warn(unused_must_use)]` on by default
[INFO] [stdout] help: use `let _ = ...` to ignore the resulting value
[INFO] [stdout]    |
[INFO] [stdout] 26 |     let _ = &v[2];
[INFO] [stdout]    |     +++++++
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused borrow that must be used
[INFO] [stdout]   --> src/std/vectors_arrays.rs:27:2
[INFO] [stdout]    |
[INFO] [stdout] 27 |     &a[2];
[INFO] [stdout]    |     ^^^^^ the borrow produces a value
[INFO] [stdout]    |
[INFO] [stdout] help: use `let _ = ...` to ignore the resulting value
[INFO] [stdout]    |
[INFO] [stdout] 27 |     let _ = &a[2];
[INFO] [stdout]    |     +++++++
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: 2 warnings emitted
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused borrow that must be used
[INFO] [stdout]   --> src/std/vectors_arrays.rs:26:2
[INFO] [stdout]    |
[INFO] [stdout] 26 |     &v[2];
[INFO] [stdout]    |     ^^^^^ the borrow produces a value
[INFO] [stdout]    |
[INFO] [stdout]    = note: `#[warn(unused_must_use)]` on by default
[INFO] [stdout] help: use `let _ = ...` to ignore the resulting value
[INFO] [stdout]    |
[INFO] [stdout] 26 |     let _ = &v[2];
[INFO] [stdout]    |     +++++++
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused borrow that must be used
[INFO] [stdout]   --> src/std/vectors_arrays.rs:27:2
[INFO] [stdout]    |
[INFO] [stdout] 27 |     &a[2];
[INFO] [stdout]    |     ^^^^^ the borrow produces a value
[INFO] [stdout]    |
[INFO] [stdout] help: use `let _ = ...` to ignore the resulting value
[INFO] [stdout]    |
[INFO] [stdout] 27 |     let _ = &a[2];
[INFO] [stdout]    |     +++++++
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: 2 warnings emitted
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stderr]     Finished dev [unoptimized + debuginfo] target(s) in 7.10s
[INFO] running `Command { std: "docker" "inspect" "04551db3f26392b9fd43c938d708a4c9a9b0c68714cc839e82f174d8cd595dc3", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "04551db3f26392b9fd43c938d708a4c9a9b0c68714cc839e82f174d8cd595dc3", kill_on_drop: false }`
[INFO] [stdout] 04551db3f26392b9fd43c938d708a4c9a9b0c68714cc839e82f174d8cd595dc3