[INFO] fetching crate serbo-mc 0.1.0...
[INFO] checking serbo-mc-0.1.0 against beta for pr-78714
[INFO] extracting crate serbo-mc 0.1.0 into /workspace/builds/worker-3/source
[INFO] validating manifest of crates.io crate serbo-mc 0.1.0 on toolchain beta
[INFO] running `Command { std: "/workspace/cargo-home/bin/cargo" "+beta" "read-manifest" "--manifest-path" "Cargo.toml", kill_on_drop: false }`
[INFO] started tweaking crates.io crate serbo-mc 0.1.0
[INFO] finished tweaking crates.io crate serbo-mc 0.1.0
[INFO] tweaked toml for crates.io crate serbo-mc 0.1.0 written to /workspace/builds/worker-3/source/Cargo.toml
[INFO] running `Command { std: "/workspace/cargo-home/bin/cargo" "+beta" "generate-lockfile" "--manifest-path" "Cargo.toml" "-Zno-index-update", kill_on_drop: false }`
[INFO] running `Command { std: "/workspace/cargo-home/bin/cargo" "+beta" "fetch" "--locked" "--manifest-path" "Cargo.toml", kill_on_drop: false }`
[INFO] [stderr]  Downloading crates ...
[INFO] [stderr]   Downloaded copy_dir v0.1.2
[INFO] [stderr]   Downloaded walkdir v0.1.8
[INFO] running `Command { std: "docker" "create" "-v" "/var/lib/crater-agent-workspace/builds/worker-3/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-3/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" "rustops/crates-build-env@sha256:6eabd152ff4036248d66efda456a36cb33d24b7291b33f25f75140726c88da35" "/opt/rustwide/cargo-home/bin/cargo" "+beta" "metadata" "--no-deps" "--format-version=1", kill_on_drop: false }`
[INFO] [stdout] 4899ec063e06d29e171efefbef3c25d7b8fe7ddec3b4f973dbd6953cbea5549c
[INFO] [stderr] WARNING: Your kernel does not support swap limit capabilities or the cgroup is not mounted. Memory limited without swap.
[INFO] running `Command { std: "docker" "start" "-a" "4899ec063e06d29e171efefbef3c25d7b8fe7ddec3b4f973dbd6953cbea5549c", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "inspect" "4899ec063e06d29e171efefbef3c25d7b8fe7ddec3b4f973dbd6953cbea5549c", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "4899ec063e06d29e171efefbef3c25d7b8fe7ddec3b4f973dbd6953cbea5549c", kill_on_drop: false }`
[INFO] [stdout] 4899ec063e06d29e171efefbef3c25d7b8fe7ddec3b4f973dbd6953cbea5549c
[INFO] running `Command { std: "docker" "create" "-v" "/var/lib/crater-agent-workspace/builds/worker-3/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-3/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" "rustops/crates-build-env@sha256:6eabd152ff4036248d66efda456a36cb33d24b7291b33f25f75140726c88da35" "/opt/rustwide/cargo-home/bin/cargo" "+beta" "check" "--frozen" "--all" "--all-targets" "--message-format=json", kill_on_drop: false }`
[INFO] [stdout] 9ec65e459dffdd756127be8383540dfa3cd9b51db2707473896b6f44f1f06a4a
[INFO] [stderr] WARNING: Your kernel does not support swap limit capabilities or the cgroup is not mounted. Memory limited without swap.
[INFO] running `Command { std: "docker" "start" "-a" "9ec65e459dffdd756127be8383540dfa3cd9b51db2707473896b6f44f1f06a4a", kill_on_drop: false }`
[INFO] [stderr]     Checking walkdir v0.1.8
[INFO] [stderr]     Checking copy_dir v0.1.2
[INFO] [stderr]     Checking serbo-mc v0.1.0 (/opt/rustwide/workdir)
[INFO] [stdout] warning: unused `std::result::Result` that must be used
[INFO] [stdout]    --> src/lib.rs:284:11
[INFO] [stdout]     |
[INFO] [stdout] 284 |           writeln!(writer, "{}", x);
[INFO] [stdout]     |           ^^^^^^^^^^^^^^^^^^^^^^^^^^
[INFO] [stdout]     |
[INFO] [stdout]     = note: `#[warn(unused_must_use)]` on by default
[INFO] [stdout]     = note: this `Result` may be an `Err` variant, which should be handled
[INFO] [stdout]     = note: this warning originates in a macro (in Nightly builds, run with -Z macro-backtrace for more info)
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused `std::result::Result` that must be used
[INFO] [stdout]    --> src/lib.rs:284:11
[INFO] [stdout]     |
[INFO] [stdout] 284 |           writeln!(writer, "{}", x);
[INFO] [stdout]     |           ^^^^^^^^^^^^^^^^^^^^^^^^^^
[INFO] [stdout]     |
[INFO] [stdout]     = note: `#[warn(unused_must_use)]` on by default
[INFO] [stdout]     = note: this `Result` may be an `Err` variant, which should be handled
[INFO] [stdout]     = note: this warning originates in a macro (in Nightly builds, run with -Z macro-backtrace for more info)
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused `std::result::Result` that must be used
[INFO] [stdout]    --> src/lib.rs:285:11
[INFO] [stdout]     |
[INFO] [stdout] 285 |           writer.flush();
[INFO] [stdout]     |           ^^^^^^^^^^^^^^^
[INFO] [stdout]     |
[INFO] [stdout]     = note: this `Result` may be an `Err` variant, which should be handled
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused `std::result::Result` that must be used
[INFO] [stdout]    --> src/lib.rs:303:7
[INFO] [stdout]     |
[INFO] [stdout] 303 |       inst.stdout_join.take().unwrap().join();
[INFO] [stdout]     |       ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
[INFO] [stdout]     |
[INFO] [stdout]     = note: this `Result` may be an `Err` variant, which should be handled
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused `std::result::Result` that must be used
[INFO] [stdout]    --> src/lib.rs:304:7
[INFO] [stdout]     |
[INFO] [stdout] 304 |       inst.stdin_join.take().unwrap().join();
[INFO] [stdout]     |       ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
[INFO] [stdout]     |
[INFO] [stdout]     = note: this `Result` may be an `Err` variant, which should be handled
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused `std::result::Result` that must be used
[INFO] [stdout]    --> src/lib.rs:285:11
[INFO] [stdout]     |
[INFO] [stdout] 285 |           writer.flush();
[INFO] [stdout]     |           ^^^^^^^^^^^^^^^
[INFO] [stdout]     |
[INFO] [stdout]     = note: this `Result` may be an `Err` variant, which should be handled
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused `std::result::Result` that must be used
[INFO] [stdout]    --> src/lib.rs:303:7
[INFO] [stdout]     |
[INFO] [stdout] 303 |       inst.stdout_join.take().unwrap().join();
[INFO] [stdout]     |       ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
[INFO] [stdout]     |
[INFO] [stdout]     = note: this `Result` may be an `Err` variant, which should be handled
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused `std::result::Result` that must be used
[INFO] [stdout]    --> src/lib.rs:304:7
[INFO] [stdout]     |
[INFO] [stdout] 304 |       inst.stdin_join.take().unwrap().join();
[INFO] [stdout]     |       ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
[INFO] [stdout]     |
[INFO] [stdout]     = note: this `Result` may be an `Err` variant, which should be handled
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: 4 warnings emitted
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: 4 warnings emitted
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stderr]     Finished dev [unoptimized + debuginfo] target(s) in 0.80s
[INFO] running `Command { std: "docker" "inspect" "9ec65e459dffdd756127be8383540dfa3cd9b51db2707473896b6f44f1f06a4a", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "9ec65e459dffdd756127be8383540dfa3cd9b51db2707473896b6f44f1f06a4a", kill_on_drop: false }`
[INFO] [stdout] 9ec65e459dffdd756127be8383540dfa3cd9b51db2707473896b6f44f1f06a4a