[INFO] cloning repository https://github.com/julianbieber/TcpClientSpeedtest
[INFO] running `Command { std: "git" "-c" "credential.helper=" "-c" "credential.helper=/workspace/cargo-home/bin/git-credential-null" "clone" "--bare" "https://github.com/julianbieber/TcpClientSpeedtest" "/workspace/cache/git-repos/https%3A%2F%2Fgithub.com%2Fjulianbieber%2FTcpClientSpeedtest", kill_on_drop: false }`
[INFO] [stderr] Cloning into bare repository '/workspace/cache/git-repos/https%3A%2F%2Fgithub.com%2Fjulianbieber%2FTcpClientSpeedtest'...
[INFO] running `Command { std: "git" "rev-parse" "HEAD", kill_on_drop: false }`
[INFO] [stdout] bdb34f2aad1cd7255b7a2c976131873f0a5fdfe2
[INFO] testing julianbieber/TcpClientSpeedtest against 1.49.0 for beta-1.50-1
[INFO] running `Command { std: "git" "clone" "/workspace/cache/git-repos/https%3A%2F%2Fgithub.com%2Fjulianbieber%2FTcpClientSpeedtest" "/workspace/builds/worker-8/source", kill_on_drop: false }`
[INFO] [stderr] Cloning into '/workspace/builds/worker-8/source'...
[INFO] [stderr] done.
[INFO] validating manifest of git repo https://github.com/julianbieber/TcpClientSpeedtest on toolchain 1.49.0
[INFO] running `Command { std: "/workspace/cargo-home/bin/cargo" "+1.49.0" "read-manifest" "--manifest-path" "Cargo.toml", kill_on_drop: false }`
[INFO] started tweaking git repo https://github.com/julianbieber/TcpClientSpeedtest
[INFO] finished tweaking git repo https://github.com/julianbieber/TcpClientSpeedtest
[INFO] tweaked toml for git repo https://github.com/julianbieber/TcpClientSpeedtest written to /workspace/builds/worker-8/source/Cargo.toml
[INFO] crate git repo https://github.com/julianbieber/TcpClientSpeedtest already has a lockfile, it will not be regenerated
[INFO] running `Command { std: "/workspace/cargo-home/bin/cargo" "+1.49.0" "fetch" "--locked" "--manifest-path" "Cargo.toml", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "create" "-v" "/var/lib/crater-agent-workspace/builds/worker-8/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-8/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:c8ac004eab7d63a0ad09a2dde3d3353ba464f767bee4de425dc8f74c46a1905e" "/opt/rustwide/cargo-home/bin/cargo" "+1.49.0" "metadata" "--no-deps" "--format-version=1", kill_on_drop: false }`
[INFO] [stdout] 48bdccabcfafd8c7c47c12fd6771aecb1e463c5ba2659992e9ddc346005467b7
[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" "48bdccabcfafd8c7c47c12fd6771aecb1e463c5ba2659992e9ddc346005467b7", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "inspect" "48bdccabcfafd8c7c47c12fd6771aecb1e463c5ba2659992e9ddc346005467b7", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "48bdccabcfafd8c7c47c12fd6771aecb1e463c5ba2659992e9ddc346005467b7", kill_on_drop: false }`
[INFO] [stdout] 48bdccabcfafd8c7c47c12fd6771aecb1e463c5ba2659992e9ddc346005467b7
[INFO] running `Command { std: "docker" "create" "-v" "/var/lib/crater-agent-workspace/builds/worker-8/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-8/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=warn" "-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:c8ac004eab7d63a0ad09a2dde3d3353ba464f767bee4de425dc8f74c46a1905e" "/opt/rustwide/cargo-home/bin/cargo" "+1.49.0" "build" "--frozen" "--message-format=json", kill_on_drop: false }`
[INFO] [stdout] 547169a782a354965b1adacaf09f1ca2407c328e89069b1c951ade5431011cde
[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" "547169a782a354965b1adacaf09f1ca2407c328e89069b1c951ade5431011cde", kill_on_drop: false }`
[INFO] [stderr]    Compiling tcp_client v0.1.0 (/opt/rustwide/workdir)
[INFO] [stdout] error[E0554]: `#![feature]` may not be used on the stable release channel
[INFO] [stdout]  --> src/main.rs:1:1
[INFO] [stdout]   |
[INFO] [stdout] 1 | #![feature(cfg_target_has_atomic)]
[INFO] [stdout]   | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused import: `Write`
[INFO] [stdout]  --> src/main.rs:8:21
[INFO] [stdout]   |
[INFO] [stdout] 8 | use std::io::{Read, Write};
[INFO] [stdout]   |                     ^^^^^
[INFO] [stdout]   |
[INFO] [stdout]   = note: `#[warn(unused_imports)]` on by default
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused import: `TcpListener`
[INFO] [stdout]  --> src/main.rs:9:16
[INFO] [stdout]   |
[INFO] [stdout] 9 | use std::net::{TcpListener, TcpStream};
[INFO] [stdout]   |                ^^^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused import: `std::time::Duration`
[INFO] [stdout]   --> src/main.rs:10:5
[INFO] [stdout]    |
[INFO] [stdout] 10 | use std::time::Duration;
[INFO] [stdout]    |     ^^^^^^^^^^^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unreachable expression
[INFO] [stdout]   --> src/main.rs:18:5
[INFO] [stdout]    |
[INFO] [stdout] 15 | /     loop {
[INFO] [stdout] 16 | |         stream.read(&mut data)?;
[INFO] [stdout] 17 | |     }
[INFO] [stdout]    | |_____- any code following this expression is unreachable
[INFO] [stdout] 18 |       Ok(0)
[INFO] [stdout]    |       ^^^^^ unreachable expression
[INFO] [stdout]    |
[INFO] [stdout]    = note: `#[warn(unreachable_code)]` on by default
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] error: aborting due to previous error; 4 warnings emitted
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] For more information about this error, try `rustc --explain E0554`.
[INFO] [stdout] 
[INFO] [stderr] error: could not compile `tcp_client`
[INFO] [stderr] 
[INFO] [stderr] To learn more, run the command again with --verbose.
[INFO] running `Command { std: "docker" "inspect" "547169a782a354965b1adacaf09f1ca2407c328e89069b1c951ade5431011cde", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "547169a782a354965b1adacaf09f1ca2407c328e89069b1c951ade5431011cde", kill_on_drop: false }`
[INFO] [stdout] 547169a782a354965b1adacaf09f1ca2407c328e89069b1c951ade5431011cde