[INFO] cloning repository https://github.com/a7p/learn-rust-stringmixer
[INFO] running `Command { std: "git" "-c" "credential.helper=" "-c" "credential.helper=/workspace/cargo-home/bin/git-credential-null" "clone" "--bare" "https://github.com/a7p/learn-rust-stringmixer" "/workspace/cache/git-repos/https%3A%2F%2Fgithub.com%2Fa7p%2Flearn-rust-stringmixer", kill_on_drop: false }`
[INFO] [stderr] Cloning into bare repository '/workspace/cache/git-repos/https%3A%2F%2Fgithub.com%2Fa7p%2Flearn-rust-stringmixer'...
[INFO] running `Command { std: "git" "rev-parse" "HEAD", kill_on_drop: false }`
[INFO] [stdout] fcb40481b878e6596a5284902fa4cf1a2a04252e
[INFO] checking a7p/learn-rust-stringmixer against master#7dc9ff5c629753b6930ecfe9a0446538b8e25fb7 for pr-85387
[INFO] running `Command { std: "git" "clone" "/workspace/cache/git-repos/https%3A%2F%2Fgithub.com%2Fa7p%2Flearn-rust-stringmixer" "/workspace/builds/worker-10/source", kill_on_drop: false }`
[INFO] [stderr] Cloning into '/workspace/builds/worker-10/source'...
[INFO] [stderr] done.
[INFO] validating manifest of git repo https://github.com/a7p/learn-rust-stringmixer on toolchain 7dc9ff5c629753b6930ecfe9a0446538b8e25fb7
[INFO] running `Command { std: "/workspace/cargo-home/bin/cargo" "+7dc9ff5c629753b6930ecfe9a0446538b8e25fb7" "metadata" "--manifest-path" "Cargo.toml" "--no-deps", kill_on_drop: false }`
[INFO] started tweaking git repo https://github.com/a7p/learn-rust-stringmixer
[INFO] finished tweaking git repo https://github.com/a7p/learn-rust-stringmixer
[INFO] tweaked toml for git repo https://github.com/a7p/learn-rust-stringmixer written to /workspace/builds/worker-10/source/Cargo.toml
[INFO] crate git repo https://github.com/a7p/learn-rust-stringmixer already has a lockfile, it will not be regenerated
[INFO] running `Command { std: "/workspace/cargo-home/bin/cargo" "+7dc9ff5c629753b6930ecfe9a0446538b8e25fb7" "fetch" "--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-10/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-10/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@sha256:20528e8c29e4536546f0102ce88568b16ea7538393a33fcca951030f7af10457" "/opt/rustwide/cargo-home/bin/cargo" "+7dc9ff5c629753b6930ecfe9a0446538b8e25fb7" "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] 4df41acbb957bf06c542f0f0b46ff49dcf904f17282cf061738e00571ca1885d
[INFO] running `Command { std: "docker" "start" "-a" "4df41acbb957bf06c542f0f0b46ff49dcf904f17282cf061738e00571ca1885d", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "inspect" "4df41acbb957bf06c542f0f0b46ff49dcf904f17282cf061738e00571ca1885d", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "4df41acbb957bf06c542f0f0b46ff49dcf904f17282cf061738e00571ca1885d", kill_on_drop: false }`
[INFO] [stdout] 4df41acbb957bf06c542f0f0b46ff49dcf904f17282cf061738e00571ca1885d
[INFO] running `Command { std: "docker" "create" "-v" "/var/lib/crater-agent-workspace/builds/worker-10/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-10/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@sha256:20528e8c29e4536546f0102ce88568b16ea7538393a33fcca951030f7af10457" "/opt/rustwide/cargo-home/bin/cargo" "+7dc9ff5c629753b6930ecfe9a0446538b8e25fb7" "check" "--frozen" "--all" "--all-targets" "--message-format=json", kill_on_drop: false }`
[INFO] [stdout] 8aa2f068ccdaac57813f3e748f13ff158b2db50f37bc5ddf140951f3639a1f7a
[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" "8aa2f068ccdaac57813f3e748f13ff158b2db50f37bc5ddf140951f3639a1f7a", kill_on_drop: false }`
[INFO] [stderr]     Blocking waiting for file lock on package cache
[INFO] [stderr]    Compiling winapi-build v0.1.1
[INFO] [stderr]     Checking winapi v0.2.5
[INFO] [stderr]     Checking unicode-segmentation v0.1.2
[INFO] [stderr]    Compiling advapi32-sys v0.1.2
[INFO] [stderr]     Checking rand v0.3.12
[INFO] [stderr]     Checking stringmixer v0.1.0 (/opt/rustwide/workdir)
[INFO] [stdout] warning: variable does not need to be mutable
[INFO] [stdout]   --> src/main.rs:20:13
[INFO] [stdout]    |
[INFO] [stdout] 20 |         let mut v = &mut g[1..l];
[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: 1 warning emitted
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: variable does not need to be mutable
[INFO] [stdout]   --> src/main.rs:20:13
[INFO] [stdout]    |
[INFO] [stdout] 20 |         let mut v = &mut g[1..l];
[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: 1 warning emitted
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stderr]     Finished dev [unoptimized + debuginfo] target(s) in 4.68s
[INFO] running `Command { std: "docker" "inspect" "8aa2f068ccdaac57813f3e748f13ff158b2db50f37bc5ddf140951f3639a1f7a", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "8aa2f068ccdaac57813f3e748f13ff158b2db50f37bc5ddf140951f3639a1f7a", kill_on_drop: false }`
[INFO] [stdout] 8aa2f068ccdaac57813f3e748f13ff158b2db50f37bc5ddf140951f3639a1f7a