[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] testing a7p/learn-rust-stringmixer against beta-2021-01-01 for beta-1.50-1
[INFO] running `Command { std: "git" "clone" "/workspace/cache/git-repos/https%3A%2F%2Fgithub.com%2Fa7p%2Flearn-rust-stringmixer" "/workspace/builds/worker-3/source", kill_on_drop: false }`
[INFO] [stderr] Cloning into '/workspace/builds/worker-3/source'...
[INFO] [stderr] done.
[INFO] validating manifest of git repo https://github.com/a7p/learn-rust-stringmixer on toolchain beta-2021-01-01
[INFO] running `Command { std: "/workspace/cargo-home/bin/cargo" "+beta-2021-01-01" "read-manifest" "--manifest-path" "Cargo.toml", 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-3/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" "+beta-2021-01-01" "fetch" "--locked" "--manifest-path" "Cargo.toml", kill_on_drop: false }`
[INFO] [stderr]     Blocking waiting for file lock on package cache
[INFO] [stderr] error: the lock file /workspace/builds/worker-3/source/Cargo.lock needs to be updated but --locked was passed to prevent this
[INFO] [stderr] If you want to try to generate the lock file without accessing the network, use the --offline flag.
[INFO] the lockfile is outdated, regenerating it
[INFO] running `Command { std: "/workspace/cargo-home/bin/cargo" "+beta-2021-01-01" "generate-lockfile" "--manifest-path" "Cargo.toml" "-Zno-index-update", kill_on_drop: false }`
[INFO] running `Command { std: "/workspace/cargo-home/bin/cargo" "+beta-2021-01-01" "fetch" "--locked" "--manifest-path" "Cargo.toml", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "create" "-v" "/var/lib/crater-agent-workspace/builds/worker-3/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-3/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:b8eeb62f26c39b23691079a6cb6de528d8e88b4d71a8f6b1d30f8ba7d9c16de9" "/opt/rustwide/cargo-home/bin/cargo" "+beta-2021-01-01" "metadata" "--no-deps" "--format-version=1", kill_on_drop: false }`
[INFO] [stdout] 412be4a4cfa78700e2662df2972c0dda30ccb7f311684f849653cc6b5ed2f628
[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" "412be4a4cfa78700e2662df2972c0dda30ccb7f311684f849653cc6b5ed2f628", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "inspect" "412be4a4cfa78700e2662df2972c0dda30ccb7f311684f849653cc6b5ed2f628", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "412be4a4cfa78700e2662df2972c0dda30ccb7f311684f849653cc6b5ed2f628", kill_on_drop: false }`
[INFO] [stdout] 412be4a4cfa78700e2662df2972c0dda30ccb7f311684f849653cc6b5ed2f628
[INFO] running `Command { std: "docker" "create" "-v" "/var/lib/crater-agent-workspace/builds/worker-3/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-3/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=warn" "-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:b8eeb62f26c39b23691079a6cb6de528d8e88b4d71a8f6b1d30f8ba7d9c16de9" "/opt/rustwide/cargo-home/bin/cargo" "+beta-2021-01-01" "build" "--frozen" "--message-format=json", kill_on_drop: false }`
[INFO] [stdout] c443a554c96af6a6f0bacf56813e46e25c70175ba95be421d3bc2241849d4f9c
[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" "c443a554c96af6a6f0bacf56813e46e25c70175ba95be421d3bc2241849d4f9c", kill_on_drop: false }`
[INFO] [stderr]    Compiling unicode-segmentation v0.1.3
[INFO] [stderr]    Compiling 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] [stderr]     Finished dev [unoptimized + debuginfo] target(s) in 2.00s
[INFO] running `Command { std: "docker" "inspect" "c443a554c96af6a6f0bacf56813e46e25c70175ba95be421d3bc2241849d4f9c", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "c443a554c96af6a6f0bacf56813e46e25c70175ba95be421d3bc2241849d4f9c", kill_on_drop: false }`
[INFO] [stdout] c443a554c96af6a6f0bacf56813e46e25c70175ba95be421d3bc2241849d4f9c
[INFO] running `Command { std: "docker" "create" "-v" "/var/lib/crater-agent-workspace/builds/worker-3/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-3/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=warn" "-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:b8eeb62f26c39b23691079a6cb6de528d8e88b4d71a8f6b1d30f8ba7d9c16de9" "/opt/rustwide/cargo-home/bin/cargo" "+beta-2021-01-01" "test" "--frozen" "--no-run" "--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] 1078c9420e63df43a8b44cf6fdd1f8a04c07924ea7dd2b55b4996898d0942d70
[INFO] running `Command { std: "docker" "start" "-a" "1078c9420e63df43a8b44cf6fdd1f8a04c07924ea7dd2b55b4996898d0942d70", kill_on_drop: false }`
[INFO] [stderr]    Compiling 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] [stderr]     Finished test [unoptimized + debuginfo] target(s) in 1.71s
[INFO] [stdout] warning: 1 warning emitted
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] running `Command { std: "docker" "inspect" "1078c9420e63df43a8b44cf6fdd1f8a04c07924ea7dd2b55b4996898d0942d70", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "1078c9420e63df43a8b44cf6fdd1f8a04c07924ea7dd2b55b4996898d0942d70", kill_on_drop: false }`
[INFO] [stdout] 1078c9420e63df43a8b44cf6fdd1f8a04c07924ea7dd2b55b4996898d0942d70
[INFO] running `Command { std: "docker" "create" "-v" "/var/lib/crater-agent-workspace/builds/worker-3/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-3/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=warn" "-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:b8eeb62f26c39b23691079a6cb6de528d8e88b4d71a8f6b1d30f8ba7d9c16de9" "/opt/rustwide/cargo-home/bin/cargo" "+beta-2021-01-01" "test" "--frozen", kill_on_drop: false }`
[INFO] [stdout] 8a32d04befd76ddfd2d252f36eaea3ea6a7df036081ce1b111502a199bd1cb84
[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" "8a32d04befd76ddfd2d252f36eaea3ea6a7df036081ce1b111502a199bd1cb84", kill_on_drop: false }`
[INFO] [stdout] 
[INFO] [stderr] warning: variable does not need to be mutable
[INFO] [stdout] running 1 test
[INFO] [stderr]   --> src/main.rs:20:13
[INFO] [stdout] test test_same ... ok
[INFO] [stderr]    |
[INFO] [stdout] 
[INFO] [stderr] 20 |         let mut v = &mut g[1..l];
[INFO] [stdout] test result: ok. 1 passed; 0 failed; 0 ignored; 0 measured; 0 filtered out; finished in 0.00s
[INFO] [stderr]    |             ----^
[INFO] [stdout] 
[INFO] [stderr]    |             |
[INFO] [stdout] 
[INFO] [stderr]    |             help: remove this `mut`
[INFO] [stdout] running 0 tests
[INFO] [stderr]    |
[INFO] [stdout] 
[INFO] [stderr]    = note: `#[warn(unused_mut)]` on by default
[INFO] [stdout] test result: ok. 0 passed; 0 failed; 0 ignored; 0 measured; 0 filtered out; finished in 0.00s
[INFO] [stderr] 
[INFO] [stdout] 
[INFO] [stderr] warning: 1 warning emitted
[INFO] [stderr] 
[INFO] [stderr] warning: variable does not need to be mutable
[INFO] [stderr]   --> src/main.rs:20:13
[INFO] [stderr]    |
[INFO] [stderr] 20 |         let mut v = &mut g[1..l];
[INFO] [stderr]    |             ----^
[INFO] [stderr]    |             |
[INFO] [stderr]    |             help: remove this `mut`
[INFO] [stderr]    |
[INFO] [stderr]    = note: `#[warn(unused_mut)]` on by default
[INFO] [stderr] 
[INFO] [stderr] warning: 1 warning emitted
[INFO] [stderr] 
[INFO] [stderr]     Finished test [unoptimized + debuginfo] target(s) in 0.02s
[INFO] [stderr]      Running /opt/rustwide/target/debug/deps/stringmixer-b5f14fa206066515
[INFO] [stderr]      Running /opt/rustwide/target/debug/deps/mixer-dc39550a5e10ba77
[INFO] running `Command { std: "docker" "inspect" "8a32d04befd76ddfd2d252f36eaea3ea6a7df036081ce1b111502a199bd1cb84", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "8a32d04befd76ddfd2d252f36eaea3ea6a7df036081ce1b111502a199bd1cb84", kill_on_drop: false }`
[INFO] [stdout] 8a32d04befd76ddfd2d252f36eaea3ea6a7df036081ce1b111502a199bd1cb84