[INFO] fetching crate serbo-mc 0.1.0...
[INFO] building serbo-mc-0.1.0 against try#4987e9d4227139400384ab59296ffee3b0fb1183 for pr-146237-2
[INFO] extracting crate serbo-mc 0.1.0 into /workspace/builds/worker-7-tc2/source
[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-7-tc2/source/Cargo.toml
[INFO] validating manifest of crates.io crate serbo-mc 0.1.0 on toolchain 4987e9d4227139400384ab59296ffee3b0fb1183
[INFO] running `Command { std: CARGO_HOME="/workspace/cargo-home" RUSTUP_HOME="/workspace/rustup-home" "/workspace/cargo-home/bin/cargo" "+4987e9d4227139400384ab59296ffee3b0fb1183" "metadata" "--manifest-path" "Cargo.toml" "--no-deps", kill_on_drop: false }`
[INFO] running `Command { std: CARGO_HOME="/workspace/cargo-home" RUSTUP_HOME="/workspace/rustup-home" "/workspace/cargo-home/bin/cargo" "+4987e9d4227139400384ab59296ffee3b0fb1183" "generate-lockfile" "--manifest-path" "Cargo.toml", kill_on_drop: false }`
[INFO] [stderr]     Updating crates.io index
[INFO] [stderr]      Locking 6 packages to latest compatible versions
[INFO] running `Command { std: CARGO_HOME="/workspace/cargo-home" RUSTUP_HOME="/workspace/rustup-home" "/workspace/cargo-home/bin/cargo" "+4987e9d4227139400384ab59296ffee3b0fb1183" "fetch" "--manifest-path" "Cargo.toml", kill_on_drop: false }`
[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:e90291280db7d1fac5b66fc6dad9f9662629e7365a55743daf9bdf73ebc4ea79" "/opt/rustwide/cargo-home/bin/cargo" "+4987e9d4227139400384ab59296ffee3b0fb1183" "metadata" "--no-deps" "--format-version=1", kill_on_drop: false }`
[INFO] [stdout] 1522139b8c75d3c489134d9bc1129f88e0dde9b18dd570385330fb13d9ec060f
[INFO] running `Command { std: "docker" "start" "-a" "1522139b8c75d3c489134d9bc1129f88e0dde9b18dd570385330fb13d9ec060f", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "inspect" "1522139b8c75d3c489134d9bc1129f88e0dde9b18dd570385330fb13d9ec060f", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "1522139b8c75d3c489134d9bc1129f88e0dde9b18dd570385330fb13d9ec060f", kill_on_drop: false }`
[INFO] [stdout] 1522139b8c75d3c489134d9bc1129f88e0dde9b18dd570385330fb13d9ec060f
[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:e90291280db7d1fac5b66fc6dad9f9662629e7365a55743daf9bdf73ebc4ea79" "/opt/rustwide/cargo-home/bin/cargo" "+4987e9d4227139400384ab59296ffee3b0fb1183" "build" "--frozen" "--message-format=json", kill_on_drop: false }`
[INFO] [stdout] 241a0c96c6656989f4063de13fdf93e7d2c62da66d729c539327c28618f1df03
[INFO] running `Command { std: "docker" "start" "-a" "241a0c96c6656989f4063de13fdf93e7d2c62da66d729c539327c28618f1df03", kill_on_drop: false }`
[INFO] [stderr]    Compiling copy_dir v0.1.3
[INFO] [stderr]    Compiling 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: this `Result` may be an `Err` variant, which should be handled
[INFO] [stdout]     = note: `#[warn(unused_must_use)]` (part of `#[warn(unused)]`) on by default
[INFO] [stdout] help: use `let _ = ...` to ignore the resulting value
[INFO] [stdout]     |
[INFO] [stdout] 284 |           let _ = writeln!(writer, "{}", x);
[INFO] [stdout]     |           +++++++
[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] help: use `let _ = ...` to ignore the resulting value
[INFO] [stdout]     |
[INFO] [stdout] 285 |           let _ = writer.flush();
[INFO] [stdout]     |           +++++++
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused borrow that must be used
[INFO] [stdout]    --> src/lib.rs:293:5
[INFO] [stdout]     |
[INFO] [stdout] 293 |     &self.servers.insert(id.to_string(), serv_inst);
[INFO] [stdout]     |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ the borrow produces a value
[INFO] [stdout]     |
[INFO] [stdout] help: use `let _ = ...` to ignore the resulting value
[INFO] [stdout]     |
[INFO] [stdout] 293 |     let _ = &self.servers.insert(id.to_string(), serv_inst);
[INFO] [stdout]     |     +++++++
[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] help: use `let _ = ...` to ignore the resulting value
[INFO] [stdout]     |
[INFO] [stdout] 303 |       let _ = inst.stdout_join.take().unwrap().join();
[INFO] [stdout]     |       +++++++
[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] help: use `let _ = ...` to ignore the resulting value
[INFO] [stdout]     |
[INFO] [stdout] 304 |       let _ = inst.stdin_join.take().unwrap().join();
[INFO] [stdout]     |       +++++++
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stderr]     Finished `dev` profile [unoptimized + debuginfo] target(s) in 0.86s
[INFO] running `Command { std: "docker" "inspect" "241a0c96c6656989f4063de13fdf93e7d2c62da66d729c539327c28618f1df03", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "241a0c96c6656989f4063de13fdf93e7d2c62da66d729c539327c28618f1df03", kill_on_drop: false }`
[INFO] [stdout] 241a0c96c6656989f4063de13fdf93e7d2c62da66d729c539327c28618f1df03
[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:e90291280db7d1fac5b66fc6dad9f9662629e7365a55743daf9bdf73ebc4ea79" "/opt/rustwide/cargo-home/bin/cargo" "+4987e9d4227139400384ab59296ffee3b0fb1183" "test" "--frozen" "--no-run" "--message-format=json", kill_on_drop: false }`
[INFO] [stdout] f8485c683406f2949341ff0cc8dea08a84a5fe1edcf334721ee40519ddd865a0
[INFO] running `Command { std: "docker" "start" "-a" "f8485c683406f2949341ff0cc8dea08a84a5fe1edcf334721ee40519ddd865a0", kill_on_drop: false }`
[INFO] [stderr]    Compiling 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: this `Result` may be an `Err` variant, which should be handled
[INFO] [stdout]     = note: `#[warn(unused_must_use)]` (part of `#[warn(unused)]`) on by default
[INFO] [stdout] help: use `let _ = ...` to ignore the resulting value
[INFO] [stdout]     |
[INFO] [stdout] 284 |           let _ = writeln!(writer, "{}", x);
[INFO] [stdout]     |           +++++++
[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] help: use `let _ = ...` to ignore the resulting value
[INFO] [stdout]     |
[INFO] [stdout] 285 |           let _ = writer.flush();
[INFO] [stdout]     |           +++++++
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused borrow that must be used
[INFO] [stdout]    --> src/lib.rs:293:5
[INFO] [stdout]     |
[INFO] [stdout] 293 |     &self.servers.insert(id.to_string(), serv_inst);
[INFO] [stdout]     |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ the borrow produces a value
[INFO] [stdout]     |
[INFO] [stdout] help: use `let _ = ...` to ignore the resulting value
[INFO] [stdout]     |
[INFO] [stdout] 293 |     let _ = &self.servers.insert(id.to_string(), serv_inst);
[INFO] [stdout]     |     +++++++
[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] help: use `let _ = ...` to ignore the resulting value
[INFO] [stdout]     |
[INFO] [stdout] 303 |       let _ = inst.stdout_join.take().unwrap().join();
[INFO] [stdout]     |       +++++++
[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] help: use `let _ = ...` to ignore the resulting value
[INFO] [stdout]     |
[INFO] [stdout] 304 |       let _ = inst.stdin_join.take().unwrap().join();
[INFO] [stdout]     |       +++++++
[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: this `Result` may be an `Err` variant, which should be handled
[INFO] [stdout]     = note: `#[warn(unused_must_use)]` (part of `#[warn(unused)]`) on by default
[INFO] [stdout] help: use `let _ = ...` to ignore the resulting value
[INFO] [stdout]     |
[INFO] [stdout] 284 |           let _ = writeln!(writer, "{}", x);
[INFO] [stdout]     |           +++++++
[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] help: use `let _ = ...` to ignore the resulting value
[INFO] [stdout]     |
[INFO] [stdout] 285 |           let _ = writer.flush();
[INFO] [stdout]     |           +++++++
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused borrow that must be used
[INFO] [stdout]    --> src/lib.rs:293:5
[INFO] [stdout]     |
[INFO] [stdout] 293 |     &self.servers.insert(id.to_string(), serv_inst);
[INFO] [stdout]     |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ the borrow produces a value
[INFO] [stdout]     |
[INFO] [stdout] help: use `let _ = ...` to ignore the resulting value
[INFO] [stdout]     |
[INFO] [stdout] 293 |     let _ = &self.servers.insert(id.to_string(), serv_inst);
[INFO] [stdout]     |     +++++++
[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] help: use `let _ = ...` to ignore the resulting value
[INFO] [stdout]     |
[INFO] [stdout] 303 |       let _ = inst.stdout_join.take().unwrap().join();
[INFO] [stdout]     |       +++++++
[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] help: use `let _ = ...` to ignore the resulting value
[INFO] [stdout]     |
[INFO] [stdout] 304 |       let _ = inst.stdin_join.take().unwrap().join();
[INFO] [stdout]     |       +++++++
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stderr]     Finished `test` profile [unoptimized + debuginfo] target(s) in 0.40s
[INFO] running `Command { std: "docker" "inspect" "f8485c683406f2949341ff0cc8dea08a84a5fe1edcf334721ee40519ddd865a0", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "f8485c683406f2949341ff0cc8dea08a84a5fe1edcf334721ee40519ddd865a0", kill_on_drop: false }`
[INFO] [stdout] f8485c683406f2949341ff0cc8dea08a84a5fe1edcf334721ee40519ddd865a0