[INFO] cloning repository https://github.com/rahulnakre/rust_channels
[INFO] running `Command { std: "git" "-c" "credential.helper=" "-c" "credential.helper=/workspace/cargo-home/bin/git-credential-null" "clone" "--bare" "https://github.com/rahulnakre/rust_channels" "/workspace/cache/git-repos/https%3A%2F%2Fgithub.com%2Frahulnakre%2Frust_channels", kill_on_drop: false }`
[INFO] [stderr] Cloning into bare repository '/workspace/cache/git-repos/https%3A%2F%2Fgithub.com%2Frahulnakre%2Frust_channels'...
[INFO] running `Command { std: "git" "rev-parse" "HEAD", kill_on_drop: false }`
[INFO] [stdout] 921033a1bacb4b2aee1342b0572b9dace0481830
[INFO] checking rahulnakre/rust_channels against master#dfd7b8d03fb93d0e03147d28b3be6d93260fa94d for pr-87050
[INFO] running `Command { std: "git" "clone" "/workspace/cache/git-repos/https%3A%2F%2Fgithub.com%2Frahulnakre%2Frust_channels" "/workspace/builds/worker-4/source", kill_on_drop: false }`
[INFO] [stderr] Cloning into '/workspace/builds/worker-4/source'...
[INFO] [stderr] done.
[INFO] validating manifest of git repo https://github.com/rahulnakre/rust_channels on toolchain dfd7b8d03fb93d0e03147d28b3be6d93260fa94d
[INFO] running `Command { std: "/workspace/cargo-home/bin/cargo" "+dfd7b8d03fb93d0e03147d28b3be6d93260fa94d" "metadata" "--manifest-path" "Cargo.toml" "--no-deps", kill_on_drop: false }`
[INFO] started tweaking git repo https://github.com/rahulnakre/rust_channels
[INFO] finished tweaking git repo https://github.com/rahulnakre/rust_channels
[INFO] tweaked toml for git repo https://github.com/rahulnakre/rust_channels written to /workspace/builds/worker-4/source/Cargo.toml
[INFO] crate git repo https://github.com/rahulnakre/rust_channels already has a lockfile, it will not be regenerated
[INFO] running `Command { std: "/workspace/cargo-home/bin/cargo" "+dfd7b8d03fb93d0e03147d28b3be6d93260fa94d" "fetch" "--manifest-path" "Cargo.toml", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "create" "-v" "/var/lib/crater-agent-workspace/builds/worker-4/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-4/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@sha256:34b6a614d2c27851fe6cbf88fbd1137609cefab8b10d0615aaeb6fd47975d74e" "/opt/rustwide/cargo-home/bin/cargo" "+dfd7b8d03fb93d0e03147d28b3be6d93260fa94d" "metadata" "--no-deps" "--format-version=1", kill_on_drop: false }`
[INFO] [stdout] e38d58d9ab080e16085b5d14016e8b04d9715349ed27ffffa2b30864d16e8c8e
[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" "e38d58d9ab080e16085b5d14016e8b04d9715349ed27ffffa2b30864d16e8c8e", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "inspect" "e38d58d9ab080e16085b5d14016e8b04d9715349ed27ffffa2b30864d16e8c8e", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "e38d58d9ab080e16085b5d14016e8b04d9715349ed27ffffa2b30864d16e8c8e", kill_on_drop: false }`
[INFO] [stdout] e38d58d9ab080e16085b5d14016e8b04d9715349ed27ffffa2b30864d16e8c8e
[INFO] running `Command { std: "docker" "create" "-v" "/var/lib/crater-agent-workspace/builds/worker-4/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-4/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" "ghcr.io/rust-lang/crates-build-env/linux@sha256:34b6a614d2c27851fe6cbf88fbd1137609cefab8b10d0615aaeb6fd47975d74e" "/opt/rustwide/cargo-home/bin/cargo" "+dfd7b8d03fb93d0e03147d28b3be6d93260fa94d" "check" "--frozen" "--all" "--all-targets" "--message-format=json", kill_on_drop: false }`
[INFO] [stderr] WARNING: Your kernel does not support swap limit capabilities or the cgroup is not mounted. Memory limited without swap.
[INFO] [stdout] cc6c1cac94b3160ad64ab46a4452187dba53c92f24a3c06e12e0c95919fe7ed8
[INFO] running `Command { std: "docker" "start" "-a" "cc6c1cac94b3160ad64ab46a4452187dba53c92f24a3c06e12e0c95919fe7ed8", kill_on_drop: false }`
[INFO] [stderr]     Checking rust_channel_from_stdlib v0.1.0 (/opt/rustwide/workdir)
[INFO] [stdout] warning: unused import: `std::thread`
[INFO] [stdout]  --> src/lib.rs:6:5
[INFO] [stdout]   |
[INFO] [stdout] 6 | use std::thread;
[INFO] [stdout]   |     ^^^^^^^^^^^
[INFO] [stdout]   |
[INFO] [stdout]   = note: `#[warn(unused_imports)]` on by default
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused import: `std::sync::mpsc`
[INFO] [stdout]  --> src/lib.rs:7:5
[INFO] [stdout]   |
[INFO] [stdout] 7 | use std::sync::mpsc;
[INFO] [stdout]   |     ^^^^^^^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: 2 warnings emitted
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `rx`
[INFO] [stdout]    --> src/lib.rs:203:22
[INFO] [stdout]     |
[INFO] [stdout] 203 |     let (mut tx, mut rx) = channel();
[INFO] [stdout]     |                      ^^ help: if this is intentional, prefix it with an underscore: `_rx`
[INFO] [stdout]     |
[INFO] [stdout]     = note: `#[warn(unused_variables)]` on by default
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `rx`
[INFO] [stdout]    --> src/lib.rs:216:14
[INFO] [stdout]     |
[INFO] [stdout] 216 |     let (tx, rx) = mpsc::channel();
[INFO] [stdout]     |              ^^ help: if this is intentional, prefix it with an underscore: `_rx`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: variable does not need to be mutable
[INFO] [stdout]    --> src/lib.rs:203:18
[INFO] [stdout]     |
[INFO] [stdout] 203 |     let (mut tx, mut rx) = channel();
[INFO] [stdout]     |                  ----^^
[INFO] [stdout]     |                  |
[INFO] [stdout]     |                  help: remove this `mut`
[INFO] [stdout]     |
[INFO] [stdout]     = note: `#[warn(unused_mut)]` on by default
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused `Result` that must be used
[INFO] [stdout]    --> src/lib.rs:217:5
[INFO] [stdout]     |
[INFO] [stdout] 217 |     tx.send(10);
[INFO] [stdout]     |     ^^^^^^^^^^^^
[INFO] [stdout]     |
[INFO] [stdout]     = note: `#[warn(unused_must_use)]` on by default
[INFO] [stdout]     = note: this `Result` may be an `Err` variant, which should be handled
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: 4 warnings emitted
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stderr]     Finished dev [unoptimized + debuginfo] target(s) in 0.80s
[INFO] running `Command { std: "docker" "inspect" "cc6c1cac94b3160ad64ab46a4452187dba53c92f24a3c06e12e0c95919fe7ed8", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "cc6c1cac94b3160ad64ab46a4452187dba53c92f24a3c06e12e0c95919fe7ed8", kill_on_drop: false }`
[INFO] [stdout] cc6c1cac94b3160ad64ab46a4452187dba53c92f24a3c06e12e0c95919fe7ed8