[INFO] cloning repository https://github.com/a74946443/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/a74946443/learn_rust" "/workspace/cache/git-repos/https%3A%2F%2Fgithub.com%2Fa74946443%2Flearn_rust", kill_on_drop: false }`
[INFO] [stderr] Cloning into bare repository '/workspace/cache/git-repos/https%3A%2F%2Fgithub.com%2Fa74946443%2Flearn_rust'...
[INFO] running `Command { std: "git" "rev-parse" "HEAD", kill_on_drop: false }`
[INFO] [stdout] d4214616a24e50a567a83e50cca030906d5f2a9f
[INFO] checking a74946443/learn_rust against master#db870ea71b6dcc7a91b999420b88f41d3cdd13e1 for pr-75192
[INFO] running `Command { std: "git" "clone" "/workspace/cache/git-repos/https%3A%2F%2Fgithub.com%2Fa74946443%2Flearn_rust" "/workspace/builds/worker-9/source", kill_on_drop: false }`
[INFO] [stderr] Cloning into '/workspace/builds/worker-9/source'...
[INFO] [stderr] done.
[INFO] validating manifest of git repo https://github.com/a74946443/learn_rust on toolchain db870ea71b6dcc7a91b999420b88f41d3cdd13e1
[INFO] running `Command { std: "/workspace/cargo-home/bin/cargo" "+db870ea71b6dcc7a91b999420b88f41d3cdd13e1" "read-manifest" "--manifest-path" "Cargo.toml", kill_on_drop: false }`
[INFO] started tweaking git repo https://github.com/a74946443/learn_rust
[INFO] finished tweaking git repo https://github.com/a74946443/learn_rust
[INFO] tweaked toml for git repo https://github.com/a74946443/learn_rust written to /workspace/builds/worker-9/source/Cargo.toml
[INFO] crate git repo https://github.com/a74946443/learn_rust already has a lockfile, it will not be regenerated
[INFO] running `Command { std: "/workspace/cargo-home/bin/cargo" "+db870ea71b6dcc7a91b999420b88f41d3cdd13e1" "fetch" "--locked" "--manifest-path" "Cargo.toml", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "create" "-v" "/var/lib/crater-agent-workspace/builds/worker-9/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-9/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:e18d859f9e32a1da89bc7b2d7d51e13b57342044d1295d9fc0dd0068c58eb3d1" "/opt/rustwide/cargo-home/bin/cargo" "+db870ea71b6dcc7a91b999420b88f41d3cdd13e1" "metadata" "--no-deps" "--format-version=1", kill_on_drop: false }`
[INFO] [stdout] 0c3e8757ff5e736c4e04b7b2a54245b04725af833eef0fb16100c6cd32d6756c
[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" "0c3e8757ff5e736c4e04b7b2a54245b04725af833eef0fb16100c6cd32d6756c", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "inspect" "0c3e8757ff5e736c4e04b7b2a54245b04725af833eef0fb16100c6cd32d6756c", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "0c3e8757ff5e736c4e04b7b2a54245b04725af833eef0fb16100c6cd32d6756c", kill_on_drop: false }`
[INFO] [stdout] 0c3e8757ff5e736c4e04b7b2a54245b04725af833eef0fb16100c6cd32d6756c
[INFO] running `Command { std: "docker" "create" "-v" "/var/lib/crater-agent-workspace/builds/worker-9/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-9/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:e18d859f9e32a1da89bc7b2d7d51e13b57342044d1295d9fc0dd0068c58eb3d1" "/opt/rustwide/cargo-home/bin/cargo" "+db870ea71b6dcc7a91b999420b88f41d3cdd13e1" "check" "--frozen" "--all" "--all-targets" "--message-format=json", kill_on_drop: false }`
[INFO] [stdout] 1df6a9e2fc4f65efcbea03de5ce62a81f5d1b10b87e24b67a8920015841d4756
[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" "1df6a9e2fc4f65efcbea03de5ce62a81f5d1b10b87e24b67a8920015841d4756", kill_on_drop: false }`
[INFO] [stderr]     Checking smallvec v0.6.10
[INFO] [stderr]    Compiling redis v0.8.0
[INFO] [stderr]     Checking percent-encoding v1.0.1
[INFO] [stderr]     Checking unicode-normalization v0.1.8
[INFO] [stderr]     Checking idna v0.1.5
[INFO] [stderr]     Checking url v1.7.2
[INFO] [stderr]     Checking simple_redis v0.3.44
[INFO] [stderr]     Checking learn_rust v0.1.0 (/opt/rustwide/workdir)
[INFO] [stdout] error[E0432]: unresolved import `learn_rust::exercise::length_of_longest_substring::substring`
[INFO] [stdout]   --> tests/exercise.rs:16:9
[INFO] [stdout]    |
[INFO] [stdout] 16 |     use learn_rust::exercise::length_of_longest_substring::substring;
[INFO] [stdout]    |         ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ no `substring` in `exercise::length_of_longest_substring`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] error: aborting due to previous error
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] For more information about this error, try `rustc --explain E0432`.
[INFO] [stdout] 
[INFO] [stderr] error: could not compile `learn_rust`.
[INFO] [stderr] 
[INFO] [stderr] To learn more, run the command again with --verbose.
[INFO] running `Command { std: "docker" "inspect" "1df6a9e2fc4f65efcbea03de5ce62a81f5d1b10b87e24b67a8920015841d4756", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "1df6a9e2fc4f65efcbea03de5ce62a81f5d1b10b87e24b67a8920015841d4756", kill_on_drop: false }`
[INFO] [stdout] 1df6a9e2fc4f65efcbea03de5ce62a81f5d1b10b87e24b67a8920015841d4756