[INFO] cloning repository https://github.com/echochamber/rust_tinkering
[INFO] running `Command { std: "git" "-c" "credential.helper=" "-c" "credential.helper=/workspace/cargo-home/bin/git-credential-null" "clone" "--bare" "https://github.com/echochamber/rust_tinkering" "/workspace/cache/git-repos/https%3A%2F%2Fgithub.com%2Fechochamber%2Frust_tinkering", kill_on_drop: false }`
[INFO] [stderr] Cloning into bare repository '/workspace/cache/git-repos/https%3A%2F%2Fgithub.com%2Fechochamber%2Frust_tinkering'...
[INFO] running `Command { std: "git" "rev-parse" "HEAD", kill_on_drop: false }`
[INFO] [stdout] 12a61eda676f034377caa5a6878c2f72db0806af
[INFO] testing echochamber/rust_tinkering against 1.49.0 for beta-1.50-1
[INFO] running `Command { std: "git" "clone" "/workspace/cache/git-repos/https%3A%2F%2Fgithub.com%2Fechochamber%2Frust_tinkering" "/workspace/builds/worker-7/source", kill_on_drop: false }`
[INFO] [stderr] Cloning into '/workspace/builds/worker-7/source'...
[INFO] [stderr] done.
[INFO] validating manifest of git repo https://github.com/echochamber/rust_tinkering on toolchain 1.49.0
[INFO] running `Command { std: "/workspace/cargo-home/bin/cargo" "+1.49.0" "read-manifest" "--manifest-path" "Cargo.toml", kill_on_drop: false }`
[INFO] started tweaking git repo https://github.com/echochamber/rust_tinkering
[INFO] finished tweaking git repo https://github.com/echochamber/rust_tinkering
[INFO] tweaked toml for git repo https://github.com/echochamber/rust_tinkering written to /workspace/builds/worker-7/source/Cargo.toml
[INFO] crate git repo https://github.com/echochamber/rust_tinkering already has a lockfile, it will not be regenerated
[INFO] running `Command { std: "/workspace/cargo-home/bin/cargo" "+1.49.0" "fetch" "--locked" "--manifest-path" "Cargo.toml", kill_on_drop: false }`
[INFO] [stderr] error: the lock file /workspace/builds/worker-7/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[INFO] the lockfile is outdated, regenerating it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" "+1.49.0" "generate-lockfile" "--manifest-path" "Cargo.toml" "-Zno-index-update", kill_on_drop: false }`
[INFO] running `Command { std: "/workspace/cargo-home/bin/cargo" "+1.49.0" "fetch" "--locked" "--manifest-path" "Cargo.toml", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "create" "-v" "/var/lib/crater-agent-workspace/builds/worker-7/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-7/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" "+1.49.0" "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] 78365d7d56f44f5475a4ef1527502f73a7bca86e2b216bc7efa8129f87b343a5
[INFO] running `Command { std: "docker" "start" "-a" "78365d7d56f44f5475a4ef1527502f73a7bca86e2b216bc7efa8129f87b343a5", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "inspect" "78365d7d56f44f5475a4ef1527502f73a7bca86e2b216bc7efa8129f87b343a5", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "78365d7d56f44f5475a4ef1527502f73a7bca86e2b216bc7efa8129f87b343a5", kill_on_drop: false }`
[INFO] [stdout] 78365d7d56f44f5475a4ef1527502f73a7bca86e2b216bc7efa8129f87b343a5
[INFO] running `Command { std: "docker" "create" "-v" "/var/lib/crater-agent-workspace/builds/worker-7/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-7/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" "+1.49.0" "build" "--frozen" "--message-format=json", kill_on_drop: false }`
[INFO] [stdout] 15ba56533ebaeb9510b82c35ed54feccb84ce4f0dcce685906c9c36c9092a882
[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" "15ba56533ebaeb9510b82c35ed54feccb84ce4f0dcce685906c9c36c9092a882", kill_on_drop: false }`
[INFO] [stderr]    Compiling rust_euler v0.0.1 (/opt/rustwide/workdir)
[INFO] [stdout] warning: unused variable: `chars`
[INFO] [stdout]  --> src/reverse_string.rs:6:9
[INFO] [stdout]   |
[INFO] [stdout] 6 |     let chars = string_to_reverse.chars();
[INFO] [stdout]   |         ^^^^^ help: if this is intentional, prefix it with an underscore: `_chars`
[INFO] [stdout]   |
[INFO] [stdout]   = note: `#[warn(unused_variables)]` 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 3.08s
[INFO] running `Command { std: "docker" "inspect" "15ba56533ebaeb9510b82c35ed54feccb84ce4f0dcce685906c9c36c9092a882", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "15ba56533ebaeb9510b82c35ed54feccb84ce4f0dcce685906c9c36c9092a882", kill_on_drop: false }`
[INFO] [stdout] 15ba56533ebaeb9510b82c35ed54feccb84ce4f0dcce685906c9c36c9092a882
[INFO] running `Command { std: "docker" "create" "-v" "/var/lib/crater-agent-workspace/builds/worker-7/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-7/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" "+1.49.0" "test" "--frozen" "--no-run" "--message-format=json", kill_on_drop: false }`
[INFO] [stdout] c293ca6fbc5ed106fb8cfd8e393ca234d214f2c8ba074a99c3c98effcf17919e
[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" "c293ca6fbc5ed106fb8cfd8e393ca234d214f2c8ba074a99c3c98effcf17919e", kill_on_drop: false }`
[INFO] [stderr]    Compiling rust_euler v0.0.1 (/opt/rustwide/workdir)
[INFO] [stdout] warning: unused variable: `chars`
[INFO] [stdout]  --> src/reverse_string.rs:6:9
[INFO] [stdout]   |
[INFO] [stdout] 6 |     let chars = string_to_reverse.chars();
[INFO] [stdout]   |         ^^^^^ help: if this is intentional, prefix it with an underscore: `_chars`
[INFO] [stdout]   |
[INFO] [stdout]   = note: `#[warn(unused_variables)]` on by default
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: 1 warning emitted
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `chars`
[INFO] [stdout]  --> src/reverse_string.rs:6:9
[INFO] [stdout]   |
[INFO] [stdout] 6 |     let chars = string_to_reverse.chars();
[INFO] [stdout]   |         ^^^^^ help: if this is intentional, prefix it with an underscore: `_chars`
[INFO] [stdout]   |
[INFO] [stdout]   = note: `#[warn(unused_variables)]` on by default
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: 1 warning emitted
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stderr]     Finished test [unoptimized + debuginfo] target(s) in 1.43s
[INFO] running `Command { std: "docker" "inspect" "c293ca6fbc5ed106fb8cfd8e393ca234d214f2c8ba074a99c3c98effcf17919e", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "c293ca6fbc5ed106fb8cfd8e393ca234d214f2c8ba074a99c3c98effcf17919e", kill_on_drop: false }`
[INFO] [stdout] c293ca6fbc5ed106fb8cfd8e393ca234d214f2c8ba074a99c3c98effcf17919e
[INFO] running `Command { std: "docker" "create" "-v" "/var/lib/crater-agent-workspace/builds/worker-7/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-7/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" "+1.49.0" "test" "--frozen", kill_on_drop: false }`
[INFO] [stdout] e80fa5b19bca63549b686de1eef78c6287311a8527136ffd3a14f62e64998643
[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" "e80fa5b19bca63549b686de1eef78c6287311a8527136ffd3a14f62e64998643", 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] [stderr] warning: unused variable: `chars`
[INFO] [stderr]  --> src/reverse_string.rs:6:9
[INFO] [stderr]   |
[INFO] [stderr] 6 |     let chars = string_to_reverse.chars();
[INFO] [stderr]   |         ^^^^^ help: if this is intentional, prefix it with an underscore: `_chars`
[INFO] [stderr]   |
[INFO] [stderr]   = note: `#[warn(unused_variables)]` on by default
[INFO] [stderr] 
[INFO] [stderr] warning: 1 warning emitted
[INFO] [stderr] 
[INFO] [stdout] 
[INFO] [stderr] warning: unused variable: `chars`
[INFO] [stdout] running 0 tests
[INFO] [stderr]  --> src/reverse_string.rs:6:9
[INFO] [stdout] 
[INFO] [stderr]   |
[INFO] [stdout] test result: ok. 0 passed; 0 failed; 0 ignored; 0 measured; 0 filtered out
[INFO] [stderr] 6 |     let chars = string_to_reverse.chars();
[INFO] [stdout] 
[INFO] [stderr]   |         ^^^^^ help: if this is intentional, prefix it with an underscore: `_chars`
[INFO] [stderr]   |
[INFO] [stderr]   = note: `#[warn(unused_variables)]` on by default
[INFO] [stderr] 
[INFO] [stderr] warning: 1 warning emitted
[INFO] [stderr] 
[INFO] [stderr]     Finished test [unoptimized + debuginfo] target(s) in 1.08s
[INFO] [stderr]      Running /opt/rustwide/target/debug/deps/rust_euler-a4116c66dcd1a6c8
[INFO] [stderr]      Running /opt/rustwide/target/debug/deps/rust_euler-6beaa5ea427b1c7c
[INFO] [stdout] 
[INFO] [stderr]    Doc-tests rust_euler
[INFO] [stdout] running 0 tests
[INFO] [stdout] 
[INFO] [stdout] test result: ok. 0 passed; 0 failed; 0 ignored; 0 measured; 0 filtered out
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] running 0 tests
[INFO] [stdout] 
[INFO] [stdout] test result: ok. 0 passed; 0 failed; 0 ignored; 0 measured; 0 filtered out
[INFO] [stdout] 
[INFO] running `Command { std: "docker" "inspect" "e80fa5b19bca63549b686de1eef78c6287311a8527136ffd3a14f62e64998643", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "e80fa5b19bca63549b686de1eef78c6287311a8527136ffd3a14f62e64998643", kill_on_drop: false }`
[INFO] [stdout] e80fa5b19bca63549b686de1eef78c6287311a8527136ffd3a14f62e64998643