[INFO] cloning repository https://github.com/sambrolia/play_ground
[INFO] running `Command { std: "git" "-c" "credential.helper=" "-c" "credential.helper=/workspace/cargo-home/bin/git-credential-null" "clone" "--bare" "https://github.com/sambrolia/play_ground" "/workspace/cache/git-repos/https%3A%2F%2Fgithub.com%2Fsambrolia%2Fplay_ground", kill_on_drop: false }`
[INFO] [stderr] Cloning into bare repository '/workspace/cache/git-repos/https%3A%2F%2Fgithub.com%2Fsambrolia%2Fplay_ground'...
[INFO] running `Command { std: "git" "rev-parse" "HEAD", kill_on_drop: false }`
[INFO] [stdout] cf849fb9e55de7d173931e3a6e0ab86c22698ecf
[INFO] checking sambrolia/play_ground against try#d990716b6a1fdde1300748828a9c9e79dfd0b898 for pr-74846
[INFO] running `Command { std: "git" "clone" "/workspace/cache/git-repos/https%3A%2F%2Fgithub.com%2Fsambrolia%2Fplay_ground" "/workspace/builds/worker-1/source", kill_on_drop: false }`
[INFO] [stderr] Cloning into '/workspace/builds/worker-1/source'...
[INFO] [stderr] done.
[INFO] validating manifest of git repo https://github.com/sambrolia/play_ground on toolchain d990716b6a1fdde1300748828a9c9e79dfd0b898
[INFO] running `Command { std: "/workspace/cargo-home/bin/cargo" "+d990716b6a1fdde1300748828a9c9e79dfd0b898" "read-manifest" "--manifest-path" "Cargo.toml", kill_on_drop: false }`
[INFO] started tweaking git repo https://github.com/sambrolia/play_ground
[INFO] finished tweaking git repo https://github.com/sambrolia/play_ground
[INFO] tweaked toml for git repo https://github.com/sambrolia/play_ground written to /workspace/builds/worker-1/source/Cargo.toml
[INFO] crate git repo https://github.com/sambrolia/play_ground already has a lockfile, it will not be regenerated
[INFO] running `Command { std: "/workspace/cargo-home/bin/cargo" "+d990716b6a1fdde1300748828a9c9e79dfd0b898" "fetch" "--locked" "--manifest-path" "Cargo.toml", kill_on_drop: false }`
[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/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-1/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:a636fd89d022f18117e1dc8fb37a0a009933cdbbe082814857f0e2024962d47c" "/opt/rustwide/cargo-home/bin/cargo" "+d990716b6a1fdde1300748828a9c9e79dfd0b898" "metadata" "--no-deps" "--format-version=1", 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] c7e23ceac2b1d0f416bee77c4d8db72f2a1b636a1e48e6a7f0f9457f7008cdbf
[INFO] running `Command { std: "docker" "start" "-a" "c7e23ceac2b1d0f416bee77c4d8db72f2a1b636a1e48e6a7f0f9457f7008cdbf", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "inspect" "c7e23ceac2b1d0f416bee77c4d8db72f2a1b636a1e48e6a7f0f9457f7008cdbf", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "c7e23ceac2b1d0f416bee77c4d8db72f2a1b636a1e48e6a7f0f9457f7008cdbf", kill_on_drop: false }`
[INFO] [stdout] c7e23ceac2b1d0f416bee77c4d8db72f2a1b636a1e48e6a7f0f9457f7008cdbf
[INFO] running `Command { std: "docker" "create" "-v" "/var/lib/crater-agent-workspace/builds/worker-1/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-1/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:a636fd89d022f18117e1dc8fb37a0a009933cdbbe082814857f0e2024962d47c" "/opt/rustwide/cargo-home/bin/cargo" "+d990716b6a1fdde1300748828a9c9e79dfd0b898" "check" "--frozen" "--all" "--all-targets" "--message-format=json", kill_on_drop: false }`
[INFO] [stdout] 619723f0aa58f2e92291d6a2806052cf779cb09269d04b059ce71b0f65e57883
[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" "619723f0aa58f2e92291d6a2806052cf779cb09269d04b059ce71b0f65e57883", kill_on_drop: false }`
[INFO] [stderr]     Checking play_ground v0.1.0 (/opt/rustwide/workdir)
[INFO] [stdout] warning: unused variable: `x`
[INFO] [stdout]   --> src/main.rs:54:9
[INFO] [stdout]    |
[INFO] [stdout] 54 |     let x = 1;
[INFO] [stdout]    |         ^ help: if this is intentional, prefix it with an underscore: `_x`
[INFO] [stdout]    |
[INFO] [stdout]    = note: `#[warn(unused_variables)]` on by default
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `a`
[INFO] [stdout]   --> src/main.rs:56:13
[INFO] [stdout]    |
[INFO] [stdout] 56 |         let a = 10;
[INFO] [stdout]    |             ^ help: if this is intentional, prefix it with an underscore: `_a`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: 2 warnings emitted
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `x`
[INFO] [stdout]   --> src/main.rs:54:9
[INFO] [stdout]    |
[INFO] [stdout] 54 |     let x = 1;
[INFO] [stdout]    |         ^ help: if this is intentional, prefix it with an underscore: `_x`
[INFO] [stdout]    |
[INFO] [stdout]    = note: `#[warn(unused_variables)]` on by default
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `a`
[INFO] [stdout]   --> src/main.rs:56:13
[INFO] [stdout]    |
[INFO] [stdout] 56 |         let a = 10;
[INFO] [stdout]    |             ^ help: if this is intentional, prefix it with an underscore: `_a`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: 2 warnings emitted
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stderr]     Finished dev [unoptimized + debuginfo] target(s) in 0.29s
[INFO] running `Command { std: "docker" "inspect" "619723f0aa58f2e92291d6a2806052cf779cb09269d04b059ce71b0f65e57883", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "619723f0aa58f2e92291d6a2806052cf779cb09269d04b059ce71b0f65e57883", kill_on_drop: false }`
[INFO] [stdout] 619723f0aa58f2e92291d6a2806052cf779cb09269d04b059ce71b0f65e57883