[INFO] cloning repository https://github.com/takkuumi/serial
[INFO] running `Command { std: "git" "-c" "credential.helper=" "-c" "credential.helper=/workspace/cargo-home/bin/git-credential-null" "clone" "--bare" "https://github.com/takkuumi/serial" "/workspace/cache/git-repos/https%3A%2F%2Fgithub.com%2Ftakkuumi%2Fserial", kill_on_drop: false }`
[INFO] [stderr] Cloning into bare repository '/workspace/cache/git-repos/https%3A%2F%2Fgithub.com%2Ftakkuumi%2Fserial'...
[INFO] running `Command { std: "git" "rev-parse" "HEAD", kill_on_drop: false }`
[INFO] [stdout] 80f2dbd3e88f4a5a166abdca3b551d9033dfc1b3
[INFO] building takkuumi/serial against master#11663cd3bfefef7d34e8f0892c250bf698049392+rustflags=-Dtail-expr-drop-order for pr-134523
[INFO] running `Command { std: "git" "clone" "/workspace/cache/git-repos/https%3A%2F%2Fgithub.com%2Ftakkuumi%2Fserial" "/workspace/builds/worker-6-tc1/source", kill_on_drop: false }`
[INFO] [stderr] Cloning into '/workspace/builds/worker-6-tc1/source'...
[INFO] [stderr] done.
[INFO] validating manifest of git repo https://github.com/takkuumi/serial on toolchain 11663cd3bfefef7d34e8f0892c250bf698049392
[INFO] running `Command { std: CARGO_HOME="/workspace/cargo-home" RUSTUP_HOME="/workspace/rustup-home" "/workspace/cargo-home/bin/cargo" "+11663cd3bfefef7d34e8f0892c250bf698049392" "metadata" "--manifest-path" "Cargo.toml" "--no-deps", kill_on_drop: false }`
[INFO] started tweaking git repo https://github.com/takkuumi/serial
[INFO] finished tweaking git repo https://github.com/takkuumi/serial
[INFO] tweaked toml for git repo https://github.com/takkuumi/serial written to /workspace/builds/worker-6-tc1/source/Cargo.toml
[INFO] crate git repo https://github.com/takkuumi/serial 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" "+11663cd3bfefef7d34e8f0892c250bf698049392" "fetch" "--manifest-path" "Cargo.toml", kill_on_drop: false }`
[INFO] [stderr]     Updating crates.io index
[INFO] [stderr]  Downloading crates ...
[INFO] [stderr]   Downloaded serialport v4.2.0
[INFO] [stderr]   Downloaded CoreFoundation-sys v0.1.4
[INFO] [stderr]   Downloaded libudev v0.3.0
[INFO] [stderr]   Downloaded mach v0.1.2
[INFO] [stderr]   Downloaded IOKit-sys v0.1.5
[INFO] running `Command { std: "docker" "create" "-v" "/var/lib/crater-agent-workspace/builds/worker-6-tc1/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-6-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:f3a9d4ad9d972b27faf3965f35b62e55ba32bbce8f20bc8fe909558a86702fde" "/opt/rustwide/cargo-home/bin/cargo" "+11663cd3bfefef7d34e8f0892c250bf698049392" "metadata" "--no-deps" "--format-version=1", kill_on_drop: false }`
[INFO] [stdout] dca7435c38d5064fd14a1bacb7596591f590e1d9544aa622a5deed1eefb623bf
[INFO] running `Command { std: "docker" "start" "-a" "dca7435c38d5064fd14a1bacb7596591f590e1d9544aa622a5deed1eefb623bf", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "inspect" "dca7435c38d5064fd14a1bacb7596591f590e1d9544aa622a5deed1eefb623bf", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "dca7435c38d5064fd14a1bacb7596591f590e1d9544aa622a5deed1eefb623bf", kill_on_drop: false }`
[INFO] [stdout] dca7435c38d5064fd14a1bacb7596591f590e1d9544aa622a5deed1eefb623bf
[INFO] running `Command { std: "docker" "create" "-v" "/var/lib/crater-agent-workspace/builds/worker-6-tc1/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-6-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 -Dtail-expr-drop-order" "-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:f3a9d4ad9d972b27faf3965f35b62e55ba32bbce8f20bc8fe909558a86702fde" "/opt/rustwide/cargo-home/bin/cargo" "+11663cd3bfefef7d34e8f0892c250bf698049392" "build" "--frozen" "--message-format=json", kill_on_drop: false }`
[INFO] [stdout] 79474a0ff442297a054a1b7c1be19289b0ab78628298abc552d591c1c5cbeeb1
[INFO] running `Command { std: "docker" "start" "-a" "79474a0ff442297a054a1b7c1be19289b0ab78628298abc552d591c1c5cbeeb1", kill_on_drop: false }`
[INFO] [stderr]    Compiling libc v0.2.140
[INFO] [stderr]    Compiling pkg-config v0.3.26
[INFO] [stderr]    Compiling cfg-if v1.0.0
[INFO] [stderr]    Compiling bitflags v1.3.2
[INFO] [stderr]    Compiling anyhow v1.0.69
[INFO] [stderr]    Compiling encoding_rs v0.8.32
[INFO] [stderr]    Compiling libudev-sys v0.1.4
[INFO] [stderr]    Compiling nix v0.24.3
[INFO] [stderr]    Compiling libudev v0.3.0
[INFO] [stderr]    Compiling serialport v4.2.0
[INFO] [stderr]    Compiling serial v0.1.0 (/opt/rustwide/workdir)
[INFO] [stdout] warning: unused variable: `size`
[INFO] [stdout]   --> src/main.rs:43:45
[INFO] [stdout]    |
[INFO] [stdout] 43 |             if let core::result::Result::Ok(size) = port.read(&mut buffer) {
[INFO] [stdout]    |                                             ^^^^ help: if this is intentional, prefix it with an underscore: `_size`
[INFO] [stdout]    |
[INFO] [stdout]    = note: `#[warn(unused_variables)]` on by default
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stderr]     Finished `dev` profile [unoptimized + debuginfo] target(s) in 6.44s
[INFO] running `Command { std: "docker" "inspect" "79474a0ff442297a054a1b7c1be19289b0ab78628298abc552d591c1c5cbeeb1", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "79474a0ff442297a054a1b7c1be19289b0ab78628298abc552d591c1c5cbeeb1", kill_on_drop: false }`
[INFO] [stdout] 79474a0ff442297a054a1b7c1be19289b0ab78628298abc552d591c1c5cbeeb1
[INFO] running `Command { std: "docker" "create" "-v" "/var/lib/crater-agent-workspace/builds/worker-6-tc1/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-6-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 -Dtail-expr-drop-order" "-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:f3a9d4ad9d972b27faf3965f35b62e55ba32bbce8f20bc8fe909558a86702fde" "/opt/rustwide/cargo-home/bin/cargo" "+11663cd3bfefef7d34e8f0892c250bf698049392" "test" "--frozen" "--no-run" "--message-format=json", kill_on_drop: false }`
[INFO] [stdout] 086346d74d09dcd9368437f611fc781ae983e75f8a85dc1dac8239fb8b7142da
[INFO] running `Command { std: "docker" "start" "-a" "086346d74d09dcd9368437f611fc781ae983e75f8a85dc1dac8239fb8b7142da", kill_on_drop: false }`
[INFO] [stderr]    Compiling serial v0.1.0 (/opt/rustwide/workdir)
[INFO] [stdout] warning: unused variable: `size`
[INFO] [stdout]   --> src/main.rs:43:45
[INFO] [stdout]    |
[INFO] [stdout] 43 |             if let core::result::Result::Ok(size) = port.read(&mut buffer) {
[INFO] [stdout]    |                                             ^^^^ help: if this is intentional, prefix it with an underscore: `_size`
[INFO] [stdout]    |
[INFO] [stdout]    = note: `#[warn(unused_variables)]` on by default
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stderr]     Finished `test` profile [unoptimized + debuginfo] target(s) in 0.39s
[INFO] running `Command { std: "docker" "inspect" "086346d74d09dcd9368437f611fc781ae983e75f8a85dc1dac8239fb8b7142da", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "086346d74d09dcd9368437f611fc781ae983e75f8a85dc1dac8239fb8b7142da", kill_on_drop: false }`
[INFO] [stdout] 086346d74d09dcd9368437f611fc781ae983e75f8a85dc1dac8239fb8b7142da