[INFO] cloning repository https://github.com/xmarsf/100-exercises-to-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/xmarsf/100-exercises-to-learn-rust" "/workspace/cache/git-repos/https%3A%2F%2Fgithub.com%2Fxmarsf%2F100-exercises-to-learn-rust", kill_on_drop: false }`
[INFO] [stderr] Cloning into bare repository '/workspace/cache/git-repos/https%3A%2F%2Fgithub.com%2Fxmarsf%2F100-exercises-to-learn-rust'...
[INFO] running `Command { std: "git" "rev-parse" "HEAD", kill_on_drop: false }`
[INFO] [stdout] 1862563f8157a11e35d73b490d51ebb4ef7c3071
[INFO] checking xmarsf/100-exercises-to-learn-rust/1862563f8157a11e35d73b490d51ebb4ef7c3071 against master#507271bc119683008ec719ecee48814e8ac86c65 for pr-146440
[INFO] running `Command { std: "git" "clone" "/workspace/cache/git-repos/https%3A%2F%2Fgithub.com%2Fxmarsf%2F100-exercises-to-learn-rust" "/workspace/builds/worker-0-tc1/source", kill_on_drop: false }`
[INFO] [stderr] Cloning into '/workspace/builds/worker-0-tc1/source'...
[INFO] [stderr] done.
[INFO] started tweaking git repo https://github.com/xmarsf/100-exercises-to-learn-rust
[INFO] finished tweaking git repo https://github.com/xmarsf/100-exercises-to-learn-rust
[INFO] tweaked toml for git repo https://github.com/xmarsf/100-exercises-to-learn-rust written to /workspace/builds/worker-0-tc1/source/Cargo.toml
[INFO] validating manifest of git repo https://github.com/xmarsf/100-exercises-to-learn-rust on toolchain 507271bc119683008ec719ecee48814e8ac86c65
[INFO] running `Command { std: CARGO_HOME="/workspace/cargo-home" RUSTUP_HOME="/workspace/rustup-home" "/workspace/cargo-home/bin/cargo" "+507271bc119683008ec719ecee48814e8ac86c65" "metadata" "--manifest-path" "Cargo.toml" "--no-deps", kill_on_drop: false }`
[INFO] crate git repo https://github.com/xmarsf/100-exercises-to-learn-rust already has a lockfile, it will not be regenerated
[INFO] running `Command { std: CARGO_HOME="/workspace/cargo-home" RUSTUP_HOME="/workspace/rustup-home" "/workspace/cargo-home/bin/cargo" "+507271bc119683008ec719ecee48814e8ac86c65" "fetch" "--manifest-path" "Cargo.toml", kill_on_drop: false }`
[INFO] [stderr]  Downloading crates ...
[INFO] [stderr]   Downloaded serde_json v1.0.148
[INFO] [stderr]   Downloaded zmij v1.0.10
[INFO] [stderr]   Downloaded escargot v0.5.15
[INFO] [stderr]   Downloaded syn v2.0.113
[INFO] [stderr]   Downloaded libc v0.2.179
[INFO] running `Command { std: "docker" "create" "-v" "/var/lib/crater-agent-workspace/builds/worker-0-tc1/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-0-tc1/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:d429b63d4308055ea97f60fb1d3dfca48854a00942f1bd2ad806beaf015945ec" "/opt/rustwide/cargo-home/bin/cargo" "+507271bc119683008ec719ecee48814e8ac86c65" "metadata" "--no-deps" "--format-version=1", kill_on_drop: false }`
[INFO] [stdout] e8dd70c3c214e43e9aeafb5d76d2fede2ac32f3541fede9ca7c38d524cb755ce
[INFO] running `Command { std: "docker" "start" "-a" "e8dd70c3c214e43e9aeafb5d76d2fede2ac32f3541fede9ca7c38d524cb755ce", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "inspect" "e8dd70c3c214e43e9aeafb5d76d2fede2ac32f3541fede9ca7c38d524cb755ce", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "e8dd70c3c214e43e9aeafb5d76d2fede2ac32f3541fede9ca7c38d524cb755ce", kill_on_drop: false }`
[INFO] [stdout] e8dd70c3c214e43e9aeafb5d76d2fede2ac32f3541fede9ca7c38d524cb755ce
[INFO] running `Command { std: "docker" "create" "-v" "/var/lib/crater-agent-workspace/builds/worker-0-tc1/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-0-tc1/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" "RUSTDOCFLAGS=--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:d429b63d4308055ea97f60fb1d3dfca48854a00942f1bd2ad806beaf015945ec" "/opt/rustwide/cargo-home/bin/cargo" "+507271bc119683008ec719ecee48814e8ac86c65" "check" "--frozen" "--all" "--all-targets" "--message-format=json", kill_on_drop: false }`
[INFO] [stdout] 387f2b958aeea7fe5ff2b5cc084b0d8123d14e19b2689719e45d1acd37ff7bb5
[INFO] running `Command { std: "docker" "start" "-a" "387f2b958aeea7fe5ff2b5cc084b0d8123d14e19b2689719e45d1acd37ff7bb5", kill_on_drop: false }`
[INFO] [stderr]    Compiling proc-macro2 v1.0.104
[INFO] [stderr]     Checking common v0.1.0 (/opt/rustwide/workdir/helpers/common)
[INFO] [stderr]    Compiling libc v0.2.179
[INFO] [stderr]    Compiling zmij v1.0.10
[INFO] [stderr]    Compiling serde_json v1.0.148
[INFO] [stderr]     Checking http v1.4.0
[INFO] [stderr]     Checking futures-channel v0.3.31
[INFO] [stderr]     Checking futures-task v0.3.31
[INFO] [stderr]     Checking sync_wrapper v1.0.2
[INFO] [stderr]    Compiling escargot v0.5.15
[INFO] [stderr]     Checking task_packages v0.1.0 (/opt/rustwide/workdir/TicketV2/Packages/Task)
[INFO] [stderr]     Checking futures-util v0.3.31
[INFO] [stderr]     Checking task_ownership v0.1.0 (/opt/rustwide/workdir/TicketV1/Ownership/Task)
[INFO] [stderr]     Checking task_futures_introduction v0.1.0 (/opt/rustwide/workdir/Futures/Introduction/Futures - Introduction)
[INFO] [stderr]     Checking task_encapsulation v0.1.0 (/opt/rustwide/workdir/TicketV1/Encapsulation/Task)
[INFO] [stdout] warning: unused import: `crate::ticket::Ticket`
[INFO] [stdout]  --> TicketV1/Encapsulation/Task/src/lib.rs:1:5
[INFO] [stdout]   |
[INFO] [stdout] 1 | use crate::ticket::Ticket;
[INFO] [stdout]   |     ^^^^^^^^^^^^^^^^^^^^^
[INFO] [stdout]   |
[INFO] [stdout]   = note: `#[warn(unused_imports)]` (part of `#[warn(unused)]`) on by default
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stderr]     Checking task_stack v0.1.0 (/opt/rustwide/workdir/TicketV1/Stack/Task)
[INFO] [stderr]     Checking task_nullability v0.1.0 (/opt/rustwide/workdir/TicketV2/Nullability/Task)
[INFO] [stderr]     Checking task_loops_for v0.1.0 (/opt/rustwide/workdir/ABasicCalculator/LoopsFor/Task)
[INFO] [stderr]     Checking task_variables v0.1.0 (/opt/rustwide/workdir/ABasicCalculator/Variables/Task)
[INFO] [stderr]     Checking task_slices v0.1.0 (/opt/rustwide/workdir/TicketManagement/Slices/Task)
[INFO] [stderr]     Checking task_integers v0.1.0 (/opt/rustwide/workdir/ABasicCalculator/Integers/Task)
[INFO] [stderr]     Checking task_copy_trait v0.1.0 (/opt/rustwide/workdir/Traits/CopyTrait/Task)
[INFO] [stdout] error[E0308]: mismatched types
[INFO] [stdout]   --> TicketV2/Nullability/Task/src/lib.rs:38:34
[INFO] [stdout]    |
[INFO] [stdout] 38 |     pub fn assigned_to(&self) -> Option<&String> {
[INFO] [stdout]    |            -----------           ^^^^^^^^^^^^^^^ expected `Option<&String>`, found `()`
[INFO] [stdout]    |            |
[INFO] [stdout]    |            implicitly returns `()` as its body has no tail or `return` expression
[INFO] [stdout]    |
[INFO] [stdout]    = note:   expected enum `Option<&String>`
[INFO] [stdout]            found unit type `()`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] For more information about this error, try `rustc --explain E0308`.
[INFO] [stdout] 
[INFO] [stderr] error: could not compile `task_nullability` (lib) due to 1 previous error
[INFO] [stderr] warning: build failed, waiting for other jobs to finish...
[INFO] [stdout] warning: field `value` is never read
[INFO] [stdout]  --> Traits/CopyTrait/Task/src/lib.rs:4:5
[INFO] [stdout]   |
[INFO] [stdout] 3 | pub struct WrappingU32 {
[INFO] [stdout]   |            ----------- field in this struct
[INFO] [stdout] 4 |     value: u32,
[INFO] [stdout]   |     ^^^^^
[INFO] [stdout]   |
[INFO] [stdout]   = note: `#[warn(dead_code)]` (part of `#[warn(unused)]`) on by default
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] running `Command { std: "docker" "inspect" "387f2b958aeea7fe5ff2b5cc084b0d8123d14e19b2689719e45d1acd37ff7bb5", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "387f2b958aeea7fe5ff2b5cc084b0d8123d14e19b2689719e45d1acd37ff7bb5", kill_on_drop: false }`
[INFO] [stdout] 387f2b958aeea7fe5ff2b5cc084b0d8123d14e19b2689719e45d1acd37ff7bb5