[INFO] cloning repository https://github.com/Nandem/Rust_learning
[INFO] running `Command { std: "git" "-c" "credential.helper=" "-c" "credential.helper=/workspace/cargo-home/bin/git-credential-null" "clone" "--bare" "https://github.com/Nandem/Rust_learning" "/workspace/cache/git-repos/https%3A%2F%2Fgithub.com%2FNandem%2FRust_learning", kill_on_drop: false }`
[INFO] [stderr] Cloning into bare repository '/workspace/cache/git-repos/https%3A%2F%2Fgithub.com%2FNandem%2FRust_learning'...
[INFO] running `Command { std: "git" "rev-parse" "HEAD", kill_on_drop: false }`
[INFO] [stdout] f6ba2518afb7cacb51835855bbd260bf98a628b1
[INFO] documenting Nandem/Rust_learning against beta-2020-08-29 for beta-1.47-rustdoc-1
[INFO] running `Command { std: "git" "clone" "/workspace/cache/git-repos/https%3A%2F%2Fgithub.com%2FNandem%2FRust_learning" "/workspace/builds/worker-6/source", kill_on_drop: false }`
[INFO] [stderr] Cloning into '/workspace/builds/worker-6/source'...
[INFO] [stderr] done.
[INFO] validating manifest of git repo https://github.com/Nandem/Rust_learning on toolchain beta-2020-08-29
[INFO] running `Command { std: "/workspace/cargo-home/bin/cargo" "+beta-2020-08-29" "read-manifest" "--manifest-path" "Cargo.toml", kill_on_drop: false }`
[INFO] started tweaking git repo https://github.com/Nandem/Rust_learning
[INFO] finished tweaking git repo https://github.com/Nandem/Rust_learning
[INFO] tweaked toml for git repo https://github.com/Nandem/Rust_learning written to /workspace/builds/worker-6/source/Cargo.toml
[INFO] crate git repo https://github.com/Nandem/Rust_learning already has a lockfile, it will not be regenerated
[INFO] running `Command { std: "/workspace/cargo-home/bin/cargo" "+beta-2020-08-29" "fetch" "--locked" "--manifest-path" "Cargo.toml", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "create" "-v" "/var/lib/crater-agent-workspace/builds/worker-6/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-6/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:d92eaeed33fa75130ca1ee6c8a01d1ffb62bac859dfdfb3450e3e5d1c0146529" "/opt/rustwide/cargo-home/bin/cargo" "+beta-2020-08-29" "metadata" "--no-deps" "--format-version=1", kill_on_drop: false }`
[INFO] [stdout] e9c2556b1321a29814b93a8fbd0e0c181852f4752544cbef0a4ba23316bac63b
[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" "e9c2556b1321a29814b93a8fbd0e0c181852f4752544cbef0a4ba23316bac63b", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "inspect" "e9c2556b1321a29814b93a8fbd0e0c181852f4752544cbef0a4ba23316bac63b", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "e9c2556b1321a29814b93a8fbd0e0c181852f4752544cbef0a4ba23316bac63b", kill_on_drop: false }`
[INFO] [stdout] e9c2556b1321a29814b93a8fbd0e0c181852f4752544cbef0a4ba23316bac63b
[INFO] running `Command { std: "docker" "create" "-v" "/var/lib/crater-agent-workspace/builds/worker-6/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-6/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" "RUSTDOCFLAGS=--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:d92eaeed33fa75130ca1ee6c8a01d1ffb62bac859dfdfb3450e3e5d1c0146529" "/opt/rustwide/cargo-home/bin/cargo" "+beta-2020-08-29" "doc" "--frozen" "--no-deps" "--document-private-items" "--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] 30f892cf4274ca3c161396750c354e38909d373724f6f3c2e14c324ffd15dbf7
[INFO] running `Command { std: "docker" "start" "-a" "30f892cf4274ca3c161396750c354e38909d373724f6f3c2e14c324ffd15dbf7", kill_on_drop: false }`
[INFO] [stderr]     Blocking waiting for file lock on package cache
[INFO] [stderr]  Documenting learning v0.1.0 (/opt/rustwide/workdir)
[INFO] [stdout] error[E0433]: failed to resolve: use of undeclared type or module `io`
[INFO] [stdout]   --> src/errors/error1.rs:39:49
[INFO] [stdout]    |
[INFO] [stdout] 39 | fn read_username_from_file1() -> Result<String, io::Error> {
[INFO] [stdout]    |                                                 ^^ use of undeclared type or module `io`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stderr] error: Could not document `learning`.
[INFO] [stdout] error[E0433]: failed to resolve: use of undeclared type or module `io`
[INFO] [stdout]   --> src/errors/error1.rs:55:49
[INFO] [stdout]    |
[INFO] [stdout] 55 | fn read_username_from_file2() -> Result<String, io::Error> {
[INFO] [stdout]    |                                                 ^^ use of undeclared type or module `io`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stderr] 
[INFO] [stdout] error[E0433]: failed to resolve: use of undeclared type or module `io`
[INFO] [stdout]   --> src/errors/error1.rs:62:49
[INFO] [stdout]    |
[INFO] [stdout] 62 | fn read_username_from_file3() -> Result<String, io::Error> {
[INFO] [stdout]    |                                                 ^^ use of undeclared type or module `io`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stderr] Caused by:
[INFO] [stdout] error: Compilation failed, aborting rustdoc
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stderr]   process didn't exit successfully: `rustdoc --crate-type lib --crate-name learning src/lib.rs -o /opt/rustwide/target/doc --error-format=json --json=diagnostic-rendered-ansi --document-private-items -L dependency=/opt/rustwide/target/debug/deps --cap-lints=warn --crate-version 0.1.0` (exit code: 1)
[INFO] [stdout] error: aborting due to 4 previous errors
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] For more information about this error, try `rustc --explain E0433`.
[INFO] [stdout] 
[INFO] running `Command { std: "docker" "inspect" "30f892cf4274ca3c161396750c354e38909d373724f6f3c2e14c324ffd15dbf7", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "30f892cf4274ca3c161396750c354e38909d373724f6f3c2e14c324ffd15dbf7", kill_on_drop: false }`
[INFO] [stdout] 30f892cf4274ca3c161396750c354e38909d373724f6f3c2e14c324ffd15dbf7