[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 try#99a443d6903f71d521237d8acb5a3016b534d17b for pr-83354
[INFO] running `Command { std: "git" "clone" "/workspace/cache/git-repos/https%3A%2F%2Fgithub.com%2Fgyng%2Frust-primer" "/workspace/builds/worker-0/source", kill_on_drop: false }`
[INFO] [stderr] Cloning into '/workspace/builds/worker-0/source'...
[INFO] [stderr] done.
[INFO] validating manifest of git repo https://github.com/gyng/rust-primer on toolchain 99a443d6903f71d521237d8acb5a3016b534d17b
[INFO] running `Command { std: "/workspace/cargo-home/bin/cargo" "+99a443d6903f71d521237d8acb5a3016b534d17b" "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-0/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" "+99a443d6903f71d521237d8acb5a3016b534d17b" "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-0/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[INFO] the lockfile is outdated, regenerating it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" "+99a443d6903f71d521237d8acb5a3016b534d17b" "generate-lockfile" "--manifest-path" "Cargo.toml" "-Zno-index-update", kill_on_drop: false }`
[INFO] running `Command { std: "/workspace/cargo-home/bin/cargo" "+99a443d6903f71d521237d8acb5a3016b534d17b" "fetch" "--locked" "--manifest-path" "Cargo.toml", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "create" "-v" "/var/lib/crater-agent-workspace/builds/worker-0/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-0/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:f2f6bcd4b43ebee4e173f653a26493129bdb64017c85f916b780ca7fbdbaa79d" "/opt/rustwide/cargo-home/bin/cargo" "+99a443d6903f71d521237d8acb5a3016b534d17b" "metadata" "--no-deps" "--format-version=1", kill_on_drop: false }`
[INFO] [stdout] 69b1feb70b7d9c09c8dd91cba8fb0cd0793e69d543fd0e12f7a9f174e0d2b2d2
[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" "69b1feb70b7d9c09c8dd91cba8fb0cd0793e69d543fd0e12f7a9f174e0d2b2d2", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "inspect" "69b1feb70b7d9c09c8dd91cba8fb0cd0793e69d543fd0e12f7a9f174e0d2b2d2", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "69b1feb70b7d9c09c8dd91cba8fb0cd0793e69d543fd0e12f7a9f174e0d2b2d2", kill_on_drop: false }`
[INFO] [stdout] 69b1feb70b7d9c09c8dd91cba8fb0cd0793e69d543fd0e12f7a9f174e0d2b2d2
[INFO] running `Command { std: "docker" "create" "-v" "/var/lib/crater-agent-workspace/builds/worker-0/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-0/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:f2f6bcd4b43ebee4e173f653a26493129bdb64017c85f916b780ca7fbdbaa79d" "/opt/rustwide/cargo-home/bin/cargo" "+99a443d6903f71d521237d8acb5a3016b534d17b" "check" "--frozen" "--all" "--all-targets" "--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] 716c7219c062dc41187ff5fe6559b73c645ddc4afa04604f14185a581930c5be
[INFO] running `Command { std: "docker" "start" "-a" "716c7219c062dc41187ff5fe6559b73c645ddc4afa04604f14185a581930c5be", kill_on_drop: false }`
[INFO] [stderr]    Compiling syn v1.0.68
[INFO] [stderr]    Compiling serde_derive v1.0.125
[INFO] [stderr]    Compiling libc v0.2.92
[INFO] [stderr]    Compiling ryu v1.0.5
[INFO] [stderr]    Compiling unicode-segmentation v1.7.1
[INFO] [stderr]    Compiling serde v1.0.125
[INFO] [stderr]    Compiling serde_json v1.0.64
[INFO] [stderr]     Checking hashbrown v0.9.1
[INFO] [stderr]     Checking unicode-width v0.1.8
[INFO] [stderr]     Checking termcolor v1.1.2
[INFO] [stderr]     Checking vec_map v0.8.2
[INFO] [stderr]     Checking strsim v0.10.0
[INFO] [stderr]     Checking itoa v0.4.7
[INFO] [stderr]     Checking os_str_bytes v2.4.0
[INFO] [stderr]     Checking exercise-libraries v0.1.0 (/opt/rustwide/workdir/07-external-libraries/exercise)
[INFO] [stderr]     Checking structs-exercise v0.1.0 (/opt/rustwide/workdir/02-basics/exercise)
[INFO] [stdout] warning: unused variable: `x`
[INFO] [stdout]   --> 02-basics/exercise/src/main.rs:16:9
[INFO] [stdout]    |
[INFO] [stdout] 16 |     let x: u8 = 1;
[INFO] [stdout]    |         ^ help: if this is intentional, prefix it with an underscore: `_x`
[INFO] [stdout]    |
[INFO] [stdout]    = note: `#[warn(unused_variables)]` on by default
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `xs`
[INFO] [stdout]   --> 02-basics/exercise/src/main.rs:28:9
[INFO] [stdout]    |
[INFO] [stdout] 28 |     let xs = [1, 2, 3, 4, 5];
[INFO] [stdout]    |         ^^ help: if this is intentional, prefix it with an underscore: `_xs`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: function is never used: `mutability`
[INFO] [stdout]  --> 02-basics/exercise/src/main.rs:3:4
[INFO] [stdout]   |
[INFO] [stdout] 3 | fn mutability() -> u8 {
[INFO] [stdout]   |    ^^^^^^^^^^
[INFO] [stdout]   |
[INFO] [stdout]   = note: `#[warn(dead_code)]` on by default
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: function is never used: `casting`
[INFO] [stdout]   --> 02-basics/exercise/src/main.rs:15:4
[INFO] [stdout]    |
[INFO] [stdout] 15 | fn casting() -> f64 {
[INFO] [stdout]    |    ^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: function is never used: `collections`
[INFO] [stdout]   --> 02-basics/exercise/src/main.rs:27:4
[INFO] [stdout]    |
[INFO] [stdout] 27 | fn collections() -> u8 {
[INFO] [stdout]    |    ^^^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: 5 warnings emitted
[INFO] [stdout] 
[INFO] [stdout] 
[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]     Checking demo-generics v0.1.0 (/opt/rustwide/workdir/04-generics-traits/demo)
[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] [stderr] error: build failed
[INFO] running `Command { std: "docker" "inspect" "716c7219c062dc41187ff5fe6559b73c645ddc4afa04604f14185a581930c5be", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "716c7219c062dc41187ff5fe6559b73c645ddc4afa04604f14185a581930c5be", kill_on_drop: false }`
[INFO] [stdout] 716c7219c062dc41187ff5fe6559b73c645ddc4afa04604f14185a581930c5be