[INFO] cloning repository https://github.com/Yu-Xiao-Sheng/learn_rust
[INFO] running `Command { std: "git" "-c" "credential.helper=" "-c" "credential.helper=/workspace/cargo-home/bin/git-credential-null" "clone" "--bare" "https://github.com/Yu-Xiao-Sheng/learn_rust" "/workspace/cache/git-repos/https%3A%2F%2Fgithub.com%2FYu-Xiao-Sheng%2Flearn_rust", kill_on_drop: false }`
[INFO] [stderr] Cloning into bare repository '/workspace/cache/git-repos/https%3A%2F%2Fgithub.com%2FYu-Xiao-Sheng%2Flearn_rust'...
[INFO] running `Command { std: "git" "rev-parse" "HEAD", kill_on_drop: false }`
[INFO] [stdout] 4df239a17af70a8343bfa78859f6b08bfae5e8fa
[INFO] checking Yu-Xiao-Sheng/learn_rust against master#9c3064e131f4939cc95a29bb11413c49bbda1491 for pr-144098
[INFO] running `Command { std: "git" "clone" "/workspace/cache/git-repos/https%3A%2F%2Fgithub.com%2FYu-Xiao-Sheng%2Flearn_rust" "/workspace/builds/worker-1-tc2/source", kill_on_drop: false }`
[INFO] [stderr] Cloning into '/workspace/builds/worker-1-tc2/source'...
[INFO] [stderr] done.
[INFO] started tweaking git repo https://github.com/Yu-Xiao-Sheng/learn_rust
[INFO] finished tweaking git repo https://github.com/Yu-Xiao-Sheng/learn_rust
[INFO] tweaked toml for git repo https://github.com/Yu-Xiao-Sheng/learn_rust written to /workspace/builds/worker-1-tc2/source/Cargo.toml
[INFO] validating manifest of git repo https://github.com/Yu-Xiao-Sheng/learn_rust on toolchain 9c3064e131f4939cc95a29bb11413c49bbda1491
[INFO] running `Command { std: CARGO_HOME="/workspace/cargo-home" RUSTUP_HOME="/workspace/rustup-home" "/workspace/cargo-home/bin/cargo" "+9c3064e131f4939cc95a29bb11413c49bbda1491" "metadata" "--manifest-path" "Cargo.toml" "--no-deps", kill_on_drop: false }`
[INFO] crate git repo https://github.com/Yu-Xiao-Sheng/learn_rust 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" "+9c3064e131f4939cc95a29bb11413c49bbda1491" "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-1-tc2/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-1-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:cf8efcab8866f2cf4285301c7418e2f4f2a9b088c91ba69c40d5b659f81557f7" "/opt/rustwide/cargo-home/bin/cargo" "+9c3064e131f4939cc95a29bb11413c49bbda1491" "metadata" "--no-deps" "--format-version=1", kill_on_drop: false }`
[INFO] [stdout] e87db7a468182a2546f4140891b5bf1d5944b9914fc5326fc2eeff8a7fddfeee
[INFO] running `Command { std: "docker" "start" "-a" "e87db7a468182a2546f4140891b5bf1d5944b9914fc5326fc2eeff8a7fddfeee", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "inspect" "e87db7a468182a2546f4140891b5bf1d5944b9914fc5326fc2eeff8a7fddfeee", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "e87db7a468182a2546f4140891b5bf1d5944b9914fc5326fc2eeff8a7fddfeee", kill_on_drop: false }`
[INFO] [stdout] e87db7a468182a2546f4140891b5bf1d5944b9914fc5326fc2eeff8a7fddfeee
[INFO] running `Command { std: "docker" "create" "-v" "/var/lib/crater-agent-workspace/builds/worker-1-tc2/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-1-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:cf8efcab8866f2cf4285301c7418e2f4f2a9b088c91ba69c40d5b659f81557f7" "/opt/rustwide/cargo-home/bin/cargo" "+9c3064e131f4939cc95a29bb11413c49bbda1491" "check" "--frozen" "--all" "--all-targets" "--message-format=json", kill_on_drop: false }`
[INFO] [stdout] c4722ca385508896e72f356c4acf6da60df78c183041117b2addf7bcb222e07e
[INFO] running `Command { std: "docker" "start" "-a" "c4722ca385508896e72f356c4acf6da60df78c183041117b2addf7bcb222e07e", kill_on_drop: false }`
[INFO] [stderr]    Compiling proc-macro2 v1.0.86
[INFO] [stderr]    Compiling unicode-ident v1.0.12
[INFO] [stderr]    Compiling autocfg v1.3.0
[INFO] [stderr]    Compiling libc v0.2.155
[INFO] [stderr]     Checking futures-sink v0.3.30
[INFO] [stderr]     Checking memchr v2.7.4
[INFO] [stderr]     Checking futures-core v0.3.30
[INFO] [stderr]     Checking pin-project-lite v0.2.14
[INFO] [stderr]    Compiling parking_lot_core v0.9.10
[INFO] [stderr]     Checking scopeguard v1.2.0
[INFO] [stderr]     Checking smallvec v1.13.2
[INFO] [stderr]     Checking futures-io v0.3.30
[INFO] [stderr]    Compiling serde v1.0.204
[INFO] [stderr]     Checking cfg-if v1.0.0
[INFO] [stderr]     Checking pin-utils v0.1.0
[INFO] [stderr]     Checking futures-task v0.3.30
[INFO] [stderr]    Compiling serde_json v1.0.121
[INFO] [stderr]     Checking itoa v1.0.11
[INFO] [stderr]     Checking ryu v1.0.18
[INFO] [stderr]     Checking bytes v1.6.1
[INFO] [stderr]     Checking futures-channel v0.3.30
[INFO] [stderr]    Compiling slab v0.4.9
[INFO] [stderr]    Compiling lock_api v0.4.12
[INFO] [stderr]    Compiling quote v1.0.36
[INFO] [stderr]    Compiling syn v2.0.72
[INFO] [stderr]     Checking mio v1.0.1
[INFO] [stderr]     Checking signal-hook-registry v1.4.2
[INFO] [stderr]     Checking socket2 v0.5.7
[INFO] [stderr]     Checking parking_lot v0.12.3
[INFO] [stderr]    Compiling futures-macro v0.3.30
[INFO] [stderr]    Compiling serde_derive v1.0.204
[INFO] [stderr]    Compiling tokio-macros v2.4.0
[INFO] [stderr]     Checking tokio v1.39.2
[INFO] [stderr]     Checking futures-util v0.3.30
[INFO] [stderr]     Checking futures-executor v0.3.30
[INFO] [stderr]     Checking futures v0.3.30
[INFO] [stderr]     Checking learn_rust v0.1.0 (/opt/rustwide/workdir)
[INFO] [stdout] warning: unused imports: `Arc`, `Mutex`, and `thread`
[INFO] [stdout]  --> src/multithreading/send_and_sync.rs:1:18
[INFO] [stdout]   |
[INFO] [stdout] 1 | use std::{sync::{Arc, Mutex}, thread};
[INFO] [stdout]   |                  ^^^  ^^^^^   ^^^^^^
[INFO] [stdout]   |
[INFO] [stdout]   = note: `#[warn(unused_imports)]` on by default
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused import: `futures::executor::block_on`
[INFO] [stdout]  --> src/async_demo/async_fun_call.rs:2:5
[INFO] [stdout]   |
[INFO] [stdout] 2 | use futures::executor::block_on;
[INFO] [stdout]   |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused label
[INFO] [stdout]  --> src/lifetimes/demo1.rs:2:5
[INFO] [stdout]   |
[INFO] [stdout] 2 |     'b: {
[INFO] [stdout]   |     ^^
[INFO] [stdout]   |
[INFO] [stdout]   = note: `#[warn(unused_labels)]` on by default
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused label
[INFO] [stdout]  --> src/lifetimes/demo1.rs:2:5
[INFO] [stdout]   |
[INFO] [stdout] 2 |     'b: {
[INFO] [stdout]   |     ^^
[INFO] [stdout]   |
[INFO] [stdout]   = note: `#[warn(unused_labels)]` on by default
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused label
[INFO] [stdout]   --> src/lifetimes/demo1.rs:10:5
[INFO] [stdout]    |
[INFO] [stdout] 10 |     'c: {
[INFO] [stdout]    |     ^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused label
[INFO] [stdout]   --> src/lifetimes/demo1.rs:12:9
[INFO] [stdout]    |
[INFO] [stdout] 12 |         'd: {
[INFO] [stdout]    |         ^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] error[E0515]: cannot return reference to local variable `s`
[INFO] [stdout]  --> src/lifetimes/demo1.rs:4:16
[INFO] [stdout]   |
[INFO] [stdout] 4 |         return &s
[INFO] [stdout]   |                ^^ returns a reference to data owned by the current function
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] For more information about this error, try `rustc --explain E0515`.
[INFO] [stdout] 
[INFO] [stderr] error: could not compile `learn_rust` (lib) due to 1 previous error; 3 warnings emitted
[INFO] [stderr] warning: build failed, waiting for other jobs to finish...
[INFO] [stdout] error[E0515]: cannot return reference to local variable `s`
[INFO] [stdout]  --> src/lifetimes/demo1.rs:4:16
[INFO] [stdout]   |
[INFO] [stdout] 4 |         return &s
[INFO] [stdout]   |                ^^ returns a reference to data owned by the current function
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] For more information about this error, try `rustc --explain E0515`.
[INFO] [stdout] 
[INFO] [stderr] error: could not compile `learn_rust` (lib test) due to 1 previous error; 3 warnings emitted
[INFO] running `Command { std: "docker" "inspect" "c4722ca385508896e72f356c4acf6da60df78c183041117b2addf7bcb222e07e", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "c4722ca385508896e72f356c4acf6da60df78c183041117b2addf7bcb222e07e", kill_on_drop: false }`
[INFO] [stdout] c4722ca385508896e72f356c4acf6da60df78c183041117b2addf7bcb222e07e