[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] checking takkuumi/serial against master#385fa9d845dd326c6bbfd58c22244215e431948a for absurd-question-mark-desugar
[INFO] running `Command { std: "git" "clone" "/workspace/cache/git-repos/https%3A%2F%2Fgithub.com%2Ftakkuumi%2Fserial" "/workspace/builds/worker-0-tc1/source", kill_on_drop: false }`
[INFO] [stderr] Cloning into '/workspace/builds/worker-0-tc1/source'...
[INFO] [stderr] done.
[INFO] validating manifest of git repo https://github.com/takkuumi/serial 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/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-0-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" "+385fa9d845dd326c6bbfd58c22244215e431948a" "fetch" "--manifest-path" "Cargo.toml", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "create" "-v" "/var/lib/crater-agent-workspace/builds/worker-0-tc1/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-0-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] d25ac112086b9d0e435cc67df05d107bc3c17af2fcade9cc839b4cef84b73251
[INFO] running `Command { std: "docker" "start" "-a" "d25ac112086b9d0e435cc67df05d107bc3c17af2fcade9cc839b4cef84b73251", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "inspect" "d25ac112086b9d0e435cc67df05d107bc3c17af2fcade9cc839b4cef84b73251", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "d25ac112086b9d0e435cc67df05d107bc3c17af2fcade9cc839b4cef84b73251", kill_on_drop: false }`
[INFO] [stdout] d25ac112086b9d0e435cc67df05d107bc3c17af2fcade9cc839b4cef84b73251
[INFO] running `Command { std: "docker" "create" "-v" "/var/lib/crater-agent-workspace/builds/worker-0-tc1/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-0-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] 3987f523aaa3812801c5d37ea73dc151860e4216009a532b52f11168ec8d533c
[INFO] running `Command { std: "docker" "start" "-a" "3987f523aaa3812801c5d37ea73dc151860e4216009a532b52f11168ec8d533c", kill_on_drop: false }`
[INFO] [stderr]    Compiling libc v0.2.140
[INFO] [stderr]    Compiling pkg-config v0.3.26
[INFO] [stderr]    Compiling anyhow v1.0.69
[INFO] [stderr]     Checking encoding_rs v0.8.32
[INFO] [stderr]    Compiling libudev-sys v0.1.4
[INFO] [stderr]     Checking nix v0.24.3
[INFO] [stderr]     Checking libudev v0.3.0
[INFO] [stderr]     Checking serialport v4.2.0
[INFO] [stderr]     Checking 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] [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] [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 3.45s
[INFO] running `Command { std: "docker" "inspect" "3987f523aaa3812801c5d37ea73dc151860e4216009a532b52f11168ec8d533c", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "3987f523aaa3812801c5d37ea73dc151860e4216009a532b52f11168ec8d533c", kill_on_drop: false }`
[INFO] [stdout] 3987f523aaa3812801c5d37ea73dc151860e4216009a532b52f11168ec8d533c
[INFO] checking takkuumi/serial against try#645bb72776a6a56a1a8f52631a44bd082b2ba509 for absurd-question-mark-desugar
[INFO] running `Command { std: "git" "clone" "/workspace/cache/git-repos/https%3A%2F%2Fgithub.com%2Ftakkuumi%2Fserial" "/workspace/builds/worker-0-tc2/source", kill_on_drop: false }`
[INFO] [stderr] Cloning into '/workspace/builds/worker-0-tc2/source'...
[INFO] [stderr] done.
[INFO] validating manifest of git repo https://github.com/takkuumi/serial 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/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-0-tc2/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" "+645bb72776a6a56a1a8f52631a44bd082b2ba509" "fetch" "--manifest-path" "Cargo.toml", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "create" "-v" "/var/lib/crater-agent-workspace/builds/worker-0-tc2/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-0-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] 418383496b7fd4a415cd9b8abaff55422ef87579e35b2d40dbb95f49ce17e374
[INFO] running `Command { std: "docker" "start" "-a" "418383496b7fd4a415cd9b8abaff55422ef87579e35b2d40dbb95f49ce17e374", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "inspect" "418383496b7fd4a415cd9b8abaff55422ef87579e35b2d40dbb95f49ce17e374", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "418383496b7fd4a415cd9b8abaff55422ef87579e35b2d40dbb95f49ce17e374", kill_on_drop: false }`
[INFO] [stdout] 418383496b7fd4a415cd9b8abaff55422ef87579e35b2d40dbb95f49ce17e374
[INFO] running `Command { std: "docker" "create" "-v" "/var/lib/crater-agent-workspace/builds/worker-0-tc2/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-0-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] 47edcd392ca91c2b3cd5eda662e07496b3466b469bf59b3be49a7315f696639f
[INFO] running `Command { std: "docker" "start" "-a" "47edcd392ca91c2b3cd5eda662e07496b3466b469bf59b3be49a7315f696639f", kill_on_drop: false }`
[INFO] [stderr]    Compiling libc v0.2.140
[INFO] [stderr]    Compiling pkg-config v0.3.26
[INFO] [stderr]    Compiling anyhow v1.0.69
[INFO] [stderr]     Checking encoding_rs v0.8.32
[INFO] [stderr]    Compiling libudev-sys v0.1.4
[INFO] [stderr]     Checking nix v0.24.3
[INFO] [stderr]     Checking libudev v0.3.0
[INFO] [stderr]     Checking serialport v4.2.0
[INFO] [stderr]     Checking 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] [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] [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 4.19s
[INFO] running `Command { std: "docker" "inspect" "47edcd392ca91c2b3cd5eda662e07496b3466b469bf59b3be49a7315f696639f", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "47edcd392ca91c2b3cd5eda662e07496b3466b469bf59b3be49a7315f696639f", kill_on_drop: false }`
[INFO] [stdout] 47edcd392ca91c2b3cd5eda662e07496b3466b469bf59b3be49a7315f696639f