[INFO] cloning repository https://github.com/adragott/Serial_Rust_Learning
[INFO] running `Command { std: "git" "-c" "credential.helper=" "-c" "credential.helper=/workspace/cargo-home/bin/git-credential-null" "clone" "--bare" "https://github.com/adragott/Serial_Rust_Learning" "/workspace/cache/git-repos/https%3A%2F%2Fgithub.com%2Fadragott%2FSerial_Rust_Learning", kill_on_drop: false }`
[INFO] [stderr] Cloning into bare repository '/workspace/cache/git-repos/https%3A%2F%2Fgithub.com%2Fadragott%2FSerial_Rust_Learning'...
[INFO] running `Command { std: "git" "rev-parse" "HEAD", kill_on_drop: false }`
[INFO] [stdout] 793ed8bd526ac92504690f517e2e45b85f92cbc9
[INFO] checking adragott/Serial_Rust_Learning against master#d62d3f7fa9a91d933213cc10e20e740608983f64 for pr-77015
[INFO] running `Command { std: "git" "clone" "/workspace/cache/git-repos/https%3A%2F%2Fgithub.com%2Fadragott%2FSerial_Rust_Learning" "/workspace/builds/worker-7/source", kill_on_drop: false }`
[INFO] [stderr] Cloning into '/workspace/builds/worker-7/source'...
[INFO] [stderr] done.
[INFO] validating manifest of git repo https://github.com/adragott/Serial_Rust_Learning on toolchain d62d3f7fa9a91d933213cc10e20e740608983f64
[INFO] running `Command { std: "/workspace/cargo-home/bin/cargo" "+d62d3f7fa9a91d933213cc10e20e740608983f64" "read-manifest" "--manifest-path" "Cargo.toml", kill_on_drop: false }`
[INFO] removed /workspace/builds/worker-7/source/.cargo/config
[INFO] started tweaking git repo https://github.com/adragott/Serial_Rust_Learning
[INFO] finished tweaking git repo https://github.com/adragott/Serial_Rust_Learning
[INFO] tweaked toml for git repo https://github.com/adragott/Serial_Rust_Learning written to /workspace/builds/worker-7/source/Cargo.toml
[INFO] crate git repo https://github.com/adragott/Serial_Rust_Learning already has a lockfile, it will not be regenerated
[INFO] running `Command { std: "/workspace/cargo-home/bin/cargo" "+d62d3f7fa9a91d933213cc10e20e740608983f64" "fetch" "--locked" "--manifest-path" "Cargo.toml", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "create" "-v" "/var/lib/crater-agent-workspace/builds/worker-7/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-7/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:d92eaeed33fa75130ca1ee6c8a01d1ffb62bac859dfdfb3450e3e5d1c0146529" "/opt/rustwide/cargo-home/bin/cargo" "+d62d3f7fa9a91d933213cc10e20e740608983f64" "metadata" "--no-deps" "--format-version=1", kill_on_drop: false }`
[INFO] [stdout] 16ef707eb54639b41c38d4bda4a507fa6c762c417cf576495a210568fb28dc77
[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" "16ef707eb54639b41c38d4bda4a507fa6c762c417cf576495a210568fb28dc77", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "inspect" "16ef707eb54639b41c38d4bda4a507fa6c762c417cf576495a210568fb28dc77", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "16ef707eb54639b41c38d4bda4a507fa6c762c417cf576495a210568fb28dc77", kill_on_drop: false }`
[INFO] [stdout] 16ef707eb54639b41c38d4bda4a507fa6c762c417cf576495a210568fb28dc77
[INFO] running `Command { std: "docker" "create" "-v" "/var/lib/crater-agent-workspace/builds/worker-7/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-7/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:d92eaeed33fa75130ca1ee6c8a01d1ffb62bac859dfdfb3450e3e5d1c0146529" "/opt/rustwide/cargo-home/bin/cargo" "+d62d3f7fa9a91d933213cc10e20e740608983f64" "check" "--frozen" "--all" "--all-targets" "--message-format=json", kill_on_drop: false }`
[INFO] [stdout] 12317a9b9756edb7baa7120120d91bbf6853f3a3e728752290d6d95d08952568
[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" "12317a9b9756edb7baa7120120d91bbf6853f3a3e728752290d6d95d08952568", kill_on_drop: false }`
[INFO] [stderr]    Compiling libc v0.2.66
[INFO] [stderr]     Checking termios v0.2.2
[INFO] [stderr]     Checking serial-core v0.4.0
[INFO] [stderr]     Checking ioctl-rs v0.1.6
[INFO] [stderr]     Checking serial-unix v0.4.0
[INFO] [stderr]     Checking serial v0.4.0
[INFO] [stderr]     Checking serial_rust v0.1.0 (/opt/rustwide/workdir)
[INFO] [stdout] warning: unused import: `std::str`
[INFO] [stdout]  --> src/main.rs:6:5
[INFO] [stdout]   |
[INFO] [stdout] 6 | use std::str;
[INFO] [stdout]   |     ^^^^^^^^
[INFO] [stdout]   |
[INFO] [stdout]   = note: `#[warn(unused_imports)]` on by default
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused import: `std::str`
[INFO] [stdout]  --> src/main.rs:6:5
[INFO] [stdout]   |
[INFO] [stdout] 6 | use std::str;
[INFO] [stdout]   |     ^^^^^^^^
[INFO] [stdout]   |
[INFO] [stdout]   = note: `#[warn(unused_imports)]` on by default
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unreachable expression
[INFO] [stdout]   --> src/main.rs:45:5
[INFO] [stdout]    |
[INFO] [stdout] 28 | /     loop
[INFO] [stdout] 29 | |     {
[INFO] [stdout] 30 | |         let mut buf = [0_u8; 256];
[INFO] [stdout] 31 | |         let count = match port.read(&mut buf)
[INFO] [stdout] ...  |
[INFO] [stdout] 43 | |         io::stdout().flush().unwrap();
[INFO] [stdout] 44 | |    }
[INFO] [stdout]    | |____- any code following this expression is unreachable
[INFO] [stdout] 45 |       Ok(())
[INFO] [stdout]    |       ^^^^^^ unreachable expression
[INFO] [stdout]    |
[INFO] [stdout]    = note: `#[warn(unreachable_code)]` on by default
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unreachable expression
[INFO] [stdout]   --> src/main.rs:45:5
[INFO] [stdout]    |
[INFO] [stdout] 28 | /     loop
[INFO] [stdout] 29 | |     {
[INFO] [stdout] 30 | |         let mut buf = [0_u8; 256];
[INFO] [stdout] 31 | |         let count = match port.read(&mut buf)
[INFO] [stdout] ...  |
[INFO] [stdout] 43 | |         io::stdout().flush().unwrap();
[INFO] [stdout] 44 | |    }
[INFO] [stdout]    | |____- any code following this expression is unreachable
[INFO] [stdout] 45 |       Ok(())
[INFO] [stdout]    |       ^^^^^^ unreachable expression
[INFO] [stdout]    |
[INFO] [stdout]    = note: `#[warn(unreachable_code)]` on by default
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: 2 warnings emitted
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stderr]     Finished dev [unoptimized + debuginfo] target(s) in 3.29s
[INFO] [stdout] warning: 2 warnings emitted
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] running `Command { std: "docker" "inspect" "12317a9b9756edb7baa7120120d91bbf6853f3a3e728752290d6d95d08952568", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "12317a9b9756edb7baa7120120d91bbf6853f3a3e728752290d6d95d08952568", kill_on_drop: false }`
[INFO] [stdout] 12317a9b9756edb7baa7120120d91bbf6853f3a3e728752290d6d95d08952568