[INFO] cloning repository https://github.com/thesophisticateddev/serial-rust-test
[INFO] running `Command { std: "git" "-c" "credential.helper=" "-c" "credential.helper=/workspace/cargo-home/bin/git-credential-null" "clone" "--bare" "https://github.com/thesophisticateddev/serial-rust-test" "/workspace/cache/git-repos/https%3A%2F%2Fgithub.com%2Fthesophisticateddev%2Fserial-rust-test", kill_on_drop: false }`
[INFO] [stderr] Cloning into bare repository '/workspace/cache/git-repos/https%3A%2F%2Fgithub.com%2Fthesophisticateddev%2Fserial-rust-test'...
[INFO] running `Command { std: "git" "rev-parse" "HEAD", kill_on_drop: false }`
[INFO] [stdout] f67dcb74b00fcd8de05af81190fdcfa977af8133
[INFO] checking thesophisticateddev/serial-rust-test against master#385fa9d845dd326c6bbfd58c22244215e431948a for absurd-question-mark-desugar
[INFO] running `Command { std: "git" "clone" "/workspace/cache/git-repos/https%3A%2F%2Fgithub.com%2Fthesophisticateddev%2Fserial-rust-test" "/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/thesophisticateddev/serial-rust-test on toolchain 385fa9d845dd326c6bbfd58c22244215e431948a
[INFO] running `Command { std: CARGO_HOME="/workspace/cargo-home" RUSTUP_HOME="/workspace/rustup-home" "/workspace/cargo-home/bin/cargo" "+385fa9d845dd326c6bbfd58c22244215e431948a" "metadata" "--manifest-path" "Cargo.toml" "--no-deps", kill_on_drop: false }`
[INFO] started tweaking git repo https://github.com/thesophisticateddev/serial-rust-test
[INFO] finished tweaking git repo https://github.com/thesophisticateddev/serial-rust-test
[INFO] tweaked toml for git repo https://github.com/thesophisticateddev/serial-rust-test written to /workspace/builds/worker-6-tc1/source/Cargo.toml
[INFO] crate git repo https://github.com/thesophisticateddev/serial-rust-test 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" "+385fa9d845dd326c6bbfd58c22244215e431948a" "fetch" "--manifest-path" "Cargo.toml", kill_on_drop: false }`
[INFO] [stderr]  Downloading crates ...
[INFO] [stderr]   Downloaded serialport v4.2.1
[INFO] [stderr]   Downloaded libudev v0.3.0
[INFO] [stderr]   Downloaded bitflags v2.0.2
[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@sha256:2788e3201cd34a07e3172128adcd8b3090168a8e3bcc40d7c032b9dda1df7d1c" "/opt/rustwide/cargo-home/bin/cargo" "+385fa9d845dd326c6bbfd58c22244215e431948a" "metadata" "--no-deps" "--format-version=1", kill_on_drop: false }`
[INFO] [stdout] cdad3d72357a49f0eb1bf57066db30e63663b87b7b962f38cdde98cf232ba36a
[INFO] running `Command { std: "docker" "start" "-a" "cdad3d72357a49f0eb1bf57066db30e63663b87b7b962f38cdde98cf232ba36a", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "inspect" "cdad3d72357a49f0eb1bf57066db30e63663b87b7b962f38cdde98cf232ba36a", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "cdad3d72357a49f0eb1bf57066db30e63663b87b7b962f38cdde98cf232ba36a", kill_on_drop: false }`
[INFO] [stdout] cdad3d72357a49f0eb1bf57066db30e63663b87b7b962f38cdde98cf232ba36a
[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" "-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" "+385fa9d845dd326c6bbfd58c22244215e431948a" "check" "--frozen" "--all" "--all-targets" "--message-format=json", kill_on_drop: false }`
[INFO] [stdout] edbac41d64e2de0a73b9b726224085de660d4d8cfdffbc07ad5f07c49a1fae5c
[INFO] running `Command { std: "docker" "start" "-a" "edbac41d64e2de0a73b9b726224085de660d4d8cfdffbc07ad5f07c49a1fae5c", kill_on_drop: false }`
[INFO] [stderr]    Compiling libc v0.2.146
[INFO] [stderr]    Compiling pkg-config v0.3.27
[INFO] [stderr]     Checking static_assertions v1.1.0
[INFO] [stderr]     Checking bitflags v2.0.2
[INFO] [stderr]     Checking scopeguard v1.1.0
[INFO] [stderr]    Compiling libudev-sys v0.1.4
[INFO] [stderr]     Checking nix v0.26.2
[INFO] [stderr]     Checking libudev v0.3.0
[INFO] [stderr]     Checking serialport v4.2.1
[INFO] [stderr]     Checking serial-rust-test v0.1.0 (/opt/rustwide/workdir)
[INFO] [stdout] warning: unused `Result` that must be used
[INFO] [stdout]   --> src/main.rs:21:5
[INFO] [stdout]    |
[INFO] [stdout] 21 |     port.flush();
[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] 21 |     let _ = port.flush();
[INFO] [stdout]    |     +++++++
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused `Result` that must be used
[INFO] [stdout]   --> src/main.rs:21:5
[INFO] [stdout]    |
[INFO] [stdout] 21 |     port.flush();
[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] 21 |     let _ = port.flush();
[INFO] [stdout]    |     +++++++
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: 1 warning emitted
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: 1 warning emitted
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stderr]     Finished `dev` profile [unoptimized + debuginfo] target(s) in 5.32s
[INFO] running `Command { std: "docker" "inspect" "edbac41d64e2de0a73b9b726224085de660d4d8cfdffbc07ad5f07c49a1fae5c", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "edbac41d64e2de0a73b9b726224085de660d4d8cfdffbc07ad5f07c49a1fae5c", kill_on_drop: false }`
[INFO] [stdout] edbac41d64e2de0a73b9b726224085de660d4d8cfdffbc07ad5f07c49a1fae5c
[INFO] checking thesophisticateddev/serial-rust-test against try#645bb72776a6a56a1a8f52631a44bd082b2ba509 for absurd-question-mark-desugar
[INFO] running `Command { std: "git" "clone" "/workspace/cache/git-repos/https%3A%2F%2Fgithub.com%2Fthesophisticateddev%2Fserial-rust-test" "/workspace/builds/worker-6-tc2/source", kill_on_drop: false }`
[INFO] [stderr] Cloning into '/workspace/builds/worker-6-tc2/source'...
[INFO] [stderr] done.
[INFO] validating manifest of git repo https://github.com/thesophisticateddev/serial-rust-test on toolchain 645bb72776a6a56a1a8f52631a44bd082b2ba509
[INFO] running `Command { std: CARGO_HOME="/workspace/cargo-home" RUSTUP_HOME="/workspace/rustup-home" "/workspace/cargo-home/bin/cargo" "+645bb72776a6a56a1a8f52631a44bd082b2ba509" "metadata" "--manifest-path" "Cargo.toml" "--no-deps", kill_on_drop: false }`
[INFO] started tweaking git repo https://github.com/thesophisticateddev/serial-rust-test
[INFO] finished tweaking git repo https://github.com/thesophisticateddev/serial-rust-test
[INFO] tweaked toml for git repo https://github.com/thesophisticateddev/serial-rust-test written to /workspace/builds/worker-6-tc2/source/Cargo.toml
[INFO] crate git repo https://github.com/thesophisticateddev/serial-rust-test 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" "+645bb72776a6a56a1a8f52631a44bd082b2ba509" "fetch" "--manifest-path" "Cargo.toml", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "create" "-v" "/var/lib/crater-agent-workspace/builds/worker-6-tc2/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-6-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" "+645bb72776a6a56a1a8f52631a44bd082b2ba509" "metadata" "--no-deps" "--format-version=1", kill_on_drop: false }`
[INFO] [stdout] 3b032d1368f25aeeaa46d104db6ee54580e84232bbda820390523ccbdeb40cae
[INFO] running `Command { std: "docker" "start" "-a" "3b032d1368f25aeeaa46d104db6ee54580e84232bbda820390523ccbdeb40cae", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "inspect" "3b032d1368f25aeeaa46d104db6ee54580e84232bbda820390523ccbdeb40cae", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "3b032d1368f25aeeaa46d104db6ee54580e84232bbda820390523ccbdeb40cae", kill_on_drop: false }`
[INFO] [stdout] 3b032d1368f25aeeaa46d104db6ee54580e84232bbda820390523ccbdeb40cae
[INFO] running `Command { std: "docker" "create" "-v" "/var/lib/crater-agent-workspace/builds/worker-6-tc2/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-6-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" "+645bb72776a6a56a1a8f52631a44bd082b2ba509" "check" "--frozen" "--all" "--all-targets" "--message-format=json", kill_on_drop: false }`
[INFO] [stdout] 9a2908423273e2543cf7ca015e67984e594b80a7d47164f6e8cb11eedcae0583
[INFO] running `Command { std: "docker" "start" "-a" "9a2908423273e2543cf7ca015e67984e594b80a7d47164f6e8cb11eedcae0583", kill_on_drop: false }`
[INFO] [stderr]    Compiling libc v0.2.146
[INFO] [stderr]    Compiling pkg-config v0.3.27
[INFO] [stderr]     Checking static_assertions v1.1.0
[INFO] [stderr]     Checking bitflags v2.0.2
[INFO] [stderr]     Checking scopeguard v1.1.0
[INFO] [stderr]    Compiling libudev-sys v0.1.4
[INFO] [stderr]     Checking nix v0.26.2
[INFO] [stderr]     Checking libudev v0.3.0
[INFO] [stderr]     Checking serialport v4.2.1
[INFO] [stderr]     Checking serial-rust-test v0.1.0 (/opt/rustwide/workdir)
[INFO] [stdout] warning: unused `Result` that must be used
[INFO] [stdout]   --> src/main.rs:21:5
[INFO] [stdout]    |
[INFO] [stdout] 21 |     port.flush();
[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] 21 |     let _ = port.flush();
[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/main.rs:21:5
[INFO] [stdout]    |
[INFO] [stdout] 21 |     port.flush();
[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] 21 |     let _ = port.flush();
[INFO] [stdout]    |     +++++++
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: 1 warning emitted
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stderr]     Finished `dev` profile [unoptimized + debuginfo] target(s) in 4.85s
[INFO] running `Command { std: "docker" "inspect" "9a2908423273e2543cf7ca015e67984e594b80a7d47164f6e8cb11eedcae0583", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "9a2908423273e2543cf7ca015e67984e594b80a7d47164f6e8cb11eedcae0583", kill_on_drop: false }`
[INFO] [stdout] 9a2908423273e2543cf7ca015e67984e594b80a7d47164f6e8cb11eedcae0583