[INFO] cloning repository https://github.com/MaciejWarchalowski/rust_hello
[INFO] running `Command { std: "git" "-c" "credential.helper=" "-c" "credential.helper=/workspace/cargo-home/bin/git-credential-null" "clone" "--bare" "https://github.com/MaciejWarchalowski/rust_hello" "/workspace/cache/git-repos/https%3A%2F%2Fgithub.com%2FMaciejWarchalowski%2Frust_hello", kill_on_drop: false }`
[INFO] [stderr] Cloning into bare repository '/workspace/cache/git-repos/https%3A%2F%2Fgithub.com%2FMaciejWarchalowski%2Frust_hello'...
[INFO] running `Command { std: "git" "rev-parse" "HEAD", kill_on_drop: false }`
[INFO] [stdout] 1939d66dd6b46eff86bbe7c56e0e92c78caeec51
[INFO] checking MaciejWarchalowski/rust_hello against try#6284d7b4bd27983dba388146648ab844ca7d032f for pr-152971
[INFO] running `Command { std: "git" "clone" "/workspace/cache/git-repos/https%3A%2F%2Fgithub.com%2FMaciejWarchalowski%2Frust_hello" "/workspace/builds/worker-5-tc2/source", kill_on_drop: false }`
[INFO] [stderr] Cloning into '/workspace/builds/worker-5-tc2/source'...
[INFO] [stderr] done.
[INFO] started tweaking git repo https://github.com/MaciejWarchalowski/rust_hello
[INFO] finished tweaking git repo https://github.com/MaciejWarchalowski/rust_hello
[INFO] tweaked toml for git repo https://github.com/MaciejWarchalowski/rust_hello written to /workspace/builds/worker-5-tc2/source/Cargo.toml
[INFO] validating manifest of git repo https://github.com/MaciejWarchalowski/rust_hello on toolchain 6284d7b4bd27983dba388146648ab844ca7d032f
[INFO] running `Command { std: CARGO_HOME="/workspace/cargo-home" RUSTUP_HOME="/workspace/rustup-home" "/workspace/cargo-home/bin/cargo" "+6284d7b4bd27983dba388146648ab844ca7d032f" "metadata" "--manifest-path" "Cargo.toml" "--no-deps", kill_on_drop: false }`
[INFO] crate git repo https://github.com/MaciejWarchalowski/rust_hello 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" "+6284d7b4bd27983dba388146648ab844ca7d032f" "fetch" "--manifest-path" "Cargo.toml", kill_on_drop: false }`
[INFO] [stderr]     Blocking waiting for file lock on package cache
[INFO] [stderr]     Blocking waiting for file lock on package cache
[INFO] running `Command { std: "docker" "create" "-v" "/var/lib/crater-agent-workspace/builds/worker-5-tc2/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-5-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@sha256:61361fe0aef631f17e9d025a70c5a647956f8c671dd02950a60ad3f5cc5526d7" "/opt/rustwide/cargo-home/bin/cargo" "+6284d7b4bd27983dba388146648ab844ca7d032f" "metadata" "--no-deps" "--format-version=1", kill_on_drop: false }`
[INFO] [stdout] 8d17cc8c539f60df4de05b94e5ef9a6a209a4b50409fe8f9fc3e1aebd4694465
[INFO] running `Command { std: "docker" "start" "-a" "8d17cc8c539f60df4de05b94e5ef9a6a209a4b50409fe8f9fc3e1aebd4694465", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "inspect" "8d17cc8c539f60df4de05b94e5ef9a6a209a4b50409fe8f9fc3e1aebd4694465", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "8d17cc8c539f60df4de05b94e5ef9a6a209a4b50409fe8f9fc3e1aebd4694465", kill_on_drop: false }`
[INFO] [stdout] 8d17cc8c539f60df4de05b94e5ef9a6a209a4b50409fe8f9fc3e1aebd4694465
[INFO] running `Command { std: "docker" "create" "-v" "/var/lib/crater-agent-workspace/builds/worker-5-tc2/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-5-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@sha256:61361fe0aef631f17e9d025a70c5a647956f8c671dd02950a60ad3f5cc5526d7" "/opt/rustwide/cargo-home/bin/cargo" "+6284d7b4bd27983dba388146648ab844ca7d032f" "check" "--frozen" "--all" "--all-targets" "--message-format=json", kill_on_drop: false }`
[INFO] [stdout] 1a956bea60fba6012e75815a6ccdcb9210adfe8c063c61889eab9c30b3fa9b49
[INFO] running `Command { std: "docker" "start" "-a" "1a956bea60fba6012e75815a6ccdcb9210adfe8c063c61889eab9c30b3fa9b49", kill_on_drop: false }`
[INFO] [stderr]     Checking hello v0.1.0 (/opt/rustwide/workdir)
[INFO] [stdout] warning: trait objects without an explicit `dyn` are deprecated
[INFO] [stdout]  --> src/lib.rs:9:16
[INFO] [stdout]   |
[INFO] [stdout] 9 | type Job = Box<FnOnce() + Send + 'static>;
[INFO] [stdout]   |                ^^^^^^^^^^^^^^^^^^^^^^^^^
[INFO] [stdout]   |
[INFO] [stdout]   = warning: this is accepted in the current edition (Rust 2018) but is a hard error in Rust 2021!
[INFO] [stdout]   = note: for more information, see <https://doc.rust-lang.org/edition-guide/rust-2021/warnings-promoted-to-error.html>
[INFO] [stdout]   = note: `#[warn(bare_trait_objects)]` (part of `#[warn(rust_2021_compatibility)]`) on by default
[INFO] [stdout] help: if this is a dyn-compatible trait, use `dyn`
[INFO] [stdout]   |
[INFO] [stdout] 9 | type Job = Box<dyn FnOnce() + Send + 'static>;
[INFO] [stdout]   |                +++
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: trait objects without an explicit `dyn` are deprecated
[INFO] [stdout]  --> src/lib.rs:9:16
[INFO] [stdout]   |
[INFO] [stdout] 9 | type Job = Box<FnOnce() + Send + 'static>;
[INFO] [stdout]   |                ^^^^^^^^^^^^^^^^^^^^^^^^^
[INFO] [stdout]   |
[INFO] [stdout]   = warning: this is accepted in the current edition (Rust 2018) but is a hard error in Rust 2021!
[INFO] [stdout]   = note: for more information, see <https://doc.rust-lang.org/edition-guide/rust-2021/warnings-promoted-to-error.html>
[INFO] [stdout]   = note: `#[warn(bare_trait_objects)]` (part of `#[warn(rust_2021_compatibility)]`) on by default
[INFO] [stdout] help: if this is a dyn-compatible trait, use `dyn`
[INFO] [stdout]   |
[INFO] [stdout] 9 | type Job = Box<dyn FnOnce() + Send + 'static>;
[INFO] [stdout]   |                +++
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: field `workers` is never read
[INFO] [stdout]  --> src/lib.rs:5:3
[INFO] [stdout]   |
[INFO] [stdout] 4 | pub struct ThreadPool {
[INFO] [stdout]   |            ---------- field in this struct
[INFO] [stdout] 5 |   workers: Vec<Worker>,
[INFO] [stdout]   |   ^^^^^^^
[INFO] [stdout]   |
[INFO] [stdout]   = note: `#[warn(dead_code)]` (part of `#[warn(unused)]`) on by default
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: field `workers` is never read
[INFO] [stdout]  --> src/lib.rs:5:3
[INFO] [stdout]   |
[INFO] [stdout] 4 | pub struct ThreadPool {
[INFO] [stdout]   |            ---------- field in this struct
[INFO] [stdout] 5 |   workers: Vec<Worker>,
[INFO] [stdout]   |   ^^^^^^^
[INFO] [stdout]   |
[INFO] [stdout]   = note: `#[warn(dead_code)]` (part of `#[warn(unused)]`) on by default
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: fields `id` and `thread` are never read
[INFO] [stdout]   --> src/lib.rs:12:3
[INFO] [stdout]    |
[INFO] [stdout] 11 | struct Worker {
[INFO] [stdout]    |        ------ fields in this struct
[INFO] [stdout] 12 |   id: usize,
[INFO] [stdout]    |   ^^
[INFO] [stdout] 13 |   thread: thread::JoinHandle<()>
[INFO] [stdout]    |   ^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: fields `id` and `thread` are never read
[INFO] [stdout]   --> src/lib.rs:12:3
[INFO] [stdout]    |
[INFO] [stdout] 11 | struct Worker {
[INFO] [stdout]    |        ------ fields in this struct
[INFO] [stdout] 12 |   id: usize,
[INFO] [stdout]    |   ^^
[INFO] [stdout] 13 |   thread: thread::JoinHandle<()>
[INFO] [stdout]    |   ^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: path statement drops value
[INFO] [stdout]   --> src/lib.rs:20:37
[INFO] [stdout]    |
[INFO] [stdout] 20 |     let thread = thread::spawn(|| { receiver; });
[INFO] [stdout]    |                                     ^^^^^^^^^ help: use `drop` to clarify the intent: `drop(receiver);`
[INFO] [stdout]    |
[INFO] [stdout]    = note: `#[warn(path_statements)]` (part of `#[warn(unused)]`) on by default
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: path statement drops value
[INFO] [stdout]   --> src/lib.rs:20:37
[INFO] [stdout]    |
[INFO] [stdout] 20 |     let thread = thread::spawn(|| { receiver; });
[INFO] [stdout]    |                                     ^^^^^^^^^ help: use `drop` to clarify the intent: `drop(receiver);`
[INFO] [stdout]    |
[INFO] [stdout]    = note: `#[warn(path_statements)]` (part of `#[warn(unused)]`) on by default
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused `Result` that must be used
[INFO] [stdout]   --> src/lib.rs:55:5
[INFO] [stdout]    |
[INFO] [stdout] 55 |     self.sender.send(job);
[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)]` (part of `#[warn(unused)]`) on by default
[INFO] [stdout] help: use `let _ = ...` to ignore the resulting value
[INFO] [stdout]    |
[INFO] [stdout] 55 |     let _ = self.sender.send(job);
[INFO] [stdout]    |     +++++++
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused `Result` that must be used
[INFO] [stdout]   --> src/lib.rs:55:5
[INFO] [stdout]    |
[INFO] [stdout] 55 |     self.sender.send(job);
[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)]` (part of `#[warn(unused)]`) on by default
[INFO] [stdout] help: use `let _ = ...` to ignore the resulting value
[INFO] [stdout]    |
[INFO] [stdout] 55 |     let _ = self.sender.send(job);
[INFO] [stdout]    |     +++++++
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stderr]     Finished `dev` profile [unoptimized + debuginfo] target(s) in 0.10s
[INFO] running `Command { std: "docker" "inspect" "1a956bea60fba6012e75815a6ccdcb9210adfe8c063c61889eab9c30b3fa9b49", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "1a956bea60fba6012e75815a6ccdcb9210adfe8c063c61889eab9c30b3fa9b49", kill_on_drop: false }`
[INFO] [stdout] 1a956bea60fba6012e75815a6ccdcb9210adfe8c063c61889eab9c30b3fa9b49