[INFO] cloning repository https://github.com/gyng/rust-primer
[INFO] running `Command { std: "git" "-c" "credential.helper=" "-c" "credential.helper=/workspace/cargo-home/bin/git-credential-null" "clone" "--bare" "https://github.com/gyng/rust-primer" "/workspace/cache/git-repos/https%3A%2F%2Fgithub.com%2Fgyng%2Frust-primer", kill_on_drop: false }`
[INFO] [stderr] Cloning into bare repository '/workspace/cache/git-repos/https%3A%2F%2Fgithub.com%2Fgyng%2Frust-primer'...
[INFO] running `Command { std: "git" "rev-parse" "HEAD", kill_on_drop: false }`
[INFO] [stdout] ed24db7d18d5c614ab80a44a1f34288f101769b0
[INFO] checking gyng/rust-primer against master#a5f164faad4a2fed606b8160fd7ecd2d5cbba381 for pr-84920
[INFO] running `Command { std: "git" "clone" "/workspace/cache/git-repos/https%3A%2F%2Fgithub.com%2Fgyng%2Frust-primer" "/workspace/builds/worker-2/source", kill_on_drop: false }`
[INFO] [stderr] Cloning into '/workspace/builds/worker-2/source'...
[INFO] [stderr] done.
[INFO] validating manifest of git repo https://github.com/gyng/rust-primer on toolchain a5f164faad4a2fed606b8160fd7ecd2d5cbba381
[INFO] running `Command { std: "/workspace/cargo-home/bin/cargo" "+a5f164faad4a2fed606b8160fd7ecd2d5cbba381" "metadata" "--manifest-path" "Cargo.toml" "--no-deps", kill_on_drop: false }`
[INFO] started tweaking git repo https://github.com/gyng/rust-primer
[INFO] finished tweaking git repo https://github.com/gyng/rust-primer
[INFO] tweaked toml for git repo https://github.com/gyng/rust-primer written to /workspace/builds/worker-2/source/Cargo.toml
[INFO] crate git repo https://github.com/gyng/rust-primer already has a lockfile, it will not be regenerated
[INFO] running `Command { std: "/workspace/cargo-home/bin/cargo" "+a5f164faad4a2fed606b8160fd7ecd2d5cbba381" "fetch" "--locked" "--manifest-path" "Cargo.toml", kill_on_drop: false }`
[INFO] [stderr] error: the lock file /workspace/builds/worker-2/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[INFO] the lockfile is outdated, regenerating it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" "+a5f164faad4a2fed606b8160fd7ecd2d5cbba381" "generate-lockfile" "--manifest-path" "Cargo.toml" "-Zno-index-update", kill_on_drop: false }`
[INFO] running `Command { std: "/workspace/cargo-home/bin/cargo" "+a5f164faad4a2fed606b8160fd7ecd2d5cbba381" "fetch" "--locked" "--manifest-path" "Cargo.toml", 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] running `Command { std: "docker" "create" "-v" "/var/lib/crater-agent-workspace/builds/worker-2/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-2/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" "+a5f164faad4a2fed606b8160fd7ecd2d5cbba381" "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] 12d17b8c09e2ccfa397b7b5a2e697c42cce4f88c14daa50b3cf0d398774ee0ec
[INFO] running `Command { std: "docker" "start" "-a" "12d17b8c09e2ccfa397b7b5a2e697c42cce4f88c14daa50b3cf0d398774ee0ec", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "inspect" "12d17b8c09e2ccfa397b7b5a2e697c42cce4f88c14daa50b3cf0d398774ee0ec", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "12d17b8c09e2ccfa397b7b5a2e697c42cce4f88c14daa50b3cf0d398774ee0ec", kill_on_drop: false }`
[INFO] [stdout] 12d17b8c09e2ccfa397b7b5a2e697c42cce4f88c14daa50b3cf0d398774ee0ec
[INFO] running `Command { std: "docker" "create" "-v" "/var/lib/crater-agent-workspace/builds/worker-2/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-2/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" "+a5f164faad4a2fed606b8160fd7ecd2d5cbba381" "check" "--frozen" "--all" "--all-targets" "--message-format=json", kill_on_drop: false }`
[INFO] [stdout] ee9e47b4db60d3a8d00efe733782948f65a5ae90ec6d3f605c5b04143b012c5f
[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" "ee9e47b4db60d3a8d00efe733782948f65a5ae90ec6d3f605c5b04143b012c5f", kill_on_drop: false }`
[INFO] [stderr]    Compiling proc-macro2 v1.0.26
[INFO] [stderr]    Compiling unicode-xid v0.2.2
[INFO] [stderr]    Compiling syn v1.0.72
[INFO] [stderr]    Compiling version_check v0.9.3
[INFO] [stderr]    Compiling serde_derive v1.0.125
[INFO] [stderr]    Compiling unicode-segmentation v1.7.1
[INFO] [stderr]    Compiling ryu v1.0.5
[INFO] [stderr]     Checking unicode-width v0.1.8
[INFO] [stderr]     Checking hashbrown v0.9.1
[INFO] [stderr]    Compiling serde_json v1.0.64
[INFO] [stderr]     Checking vec_map v0.8.2
[INFO] [stderr]     Checking demo-generics v0.1.0 (/opt/rustwide/workdir/04-generics-traits/demo)
[INFO] [stderr]     Checking solution v0.1.0 (/opt/rustwide/workdir/01-hello/solution)
[INFO] [stderr]     Checking demo-strings v0.1.0 (/opt/rustwide/workdir/06-strings/demo)
[INFO] [stderr]     Checking exercise-hello v0.1.0 (/opt/rustwide/workdir/01-hello/exercise)
[INFO] [stderr]     Checking exercise-libraries v0.1.0 (/opt/rustwide/workdir/07-external-libraries/exercise)
[INFO] [stdout] error: expected one of `!` or `::`, found `:`
[INFO] [stdout]   --> 07-external-libraries/exercise/src/main.rs:21:6
[INFO] [stdout]    |
[INFO] [stdout] 21 | https://docs.serde.rs/serde_json/#parsing-json-as-strongly-typed-data-structures
[INFO] [stdout]    |      ^ expected one of `!` or `::`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] error: aborting due to previous error
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stderr] error: could not compile `exercise-libraries`
[INFO] [stderr] 
[INFO] [stderr] To learn more, run the command again with --verbose.
[INFO] [stderr] warning: build failed, waiting for other jobs to finish...
[INFO] [stdout] warning: unused variable: `s2`
[INFO] [stdout]  --> 06-strings/demo/src/main.rs:7:9
[INFO] [stdout]   |
[INFO] [stdout] 7 |     let s2: String = String::from_str(s).unwrap(); // s could be invalid bytes for a String
[INFO] [stdout]   |         ^^ help: if this is intentional, prefix it with an underscore: `_s2`
[INFO] [stdout]   |
[INFO] [stdout]   = note: `#[warn(unused_variables)]` on by default
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `s2`
[INFO] [stdout]  --> 06-strings/demo/src/main.rs:8:9
[INFO] [stdout]   |
[INFO] [stdout] 8 |     let s2: String = s.to_owned();
[INFO] [stdout]   |         ^^ help: if this is intentional, prefix it with an underscore: `_s2`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `s3`
[INFO] [stdout]   --> 06-strings/demo/src/main.rs:17:9
[INFO] [stdout]    |
[INFO] [stdout] 17 |     let s3: &str = s2.as_str();
[INFO] [stdout]    |         ^^ help: if this is intentional, prefix it with an underscore: `_s3`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: 3 warnings emitted
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stderr] error: build failed
[INFO] running `Command { std: "docker" "inspect" "ee9e47b4db60d3a8d00efe733782948f65a5ae90ec6d3f605c5b04143b012c5f", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "ee9e47b4db60d3a8d00efe733782948f65a5ae90ec6d3f605c5b04143b012c5f", kill_on_drop: false }`
[INFO] [stdout] ee9e47b4db60d3a8d00efe733782948f65a5ae90ec6d3f605c5b04143b012c5f