[INFO] cloning repository https://github.com/luna7111/rustlings
[INFO] running `Command { std: "git" "-c" "credential.helper=" "-c" "credential.helper=/workspace/cargo-home/bin/git-credential-null" "clone" "--bare" "https://github.com/luna7111/rustlings" "/workspace/cache/git-repos/https%3A%2F%2Fgithub.com%2Fluna7111%2Frustlings", kill_on_drop: false }`
[INFO] [stderr] Cloning into bare repository '/workspace/cache/git-repos/https%3A%2F%2Fgithub.com%2Fluna7111%2Frustlings'...
[INFO] running `Command { std: "git" "rev-parse" "HEAD", kill_on_drop: false }`
[INFO] [stdout] c074d36e717454207763b85167dba505993f108a
[INFO] testing luna7111/rustlings against beta-2026-04-21 for beta-1.96-2
[INFO] running `Command { std: "git" "clone" "/workspace/cache/git-repos/https%3A%2F%2Fgithub.com%2Fluna7111%2Frustlings" "/workspace/builds/worker-0-tc2/source", kill_on_drop: false }`
[INFO] [stderr] Cloning into '/workspace/builds/worker-0-tc2/source'...
[INFO] [stderr] done.
[INFO] started tweaking git repo https://github.com/luna7111/rustlings
[INFO] finished tweaking git repo https://github.com/luna7111/rustlings
[INFO] tweaked toml for git repo https://github.com/luna7111/rustlings written to /workspace/builds/worker-0-tc2/source/Cargo.toml
[INFO] validating manifest of git repo https://github.com/luna7111/rustlings on toolchain beta-2026-04-21
[INFO] running `Command { std: CARGO_HOME="/workspace/cargo-home" RUSTUP_HOME="/workspace/rustup-home" "/workspace/cargo-home/bin/cargo" "+beta-2026-04-21" "metadata" "--manifest-path" "Cargo.toml" "--no-deps", kill_on_drop: false }`
[INFO] crate git repo https://github.com/luna7111/rustlings 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" "+beta-2026-04-21" "fetch" "--manifest-path" "Cargo.toml", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "create" "-v" "/var/lib/crater-agent-workspace/builds/worker-0-tc2/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-0-tc2/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" "+beta-2026-04-21" "metadata" "--no-deps" "--format-version=1", kill_on_drop: false }`
[INFO] [stdout] ddac7a5a4b426a13808e393d52b10365bf1df3cd5cc46b62bd29b830605cc1b3
[INFO] running `Command { std: "docker" "start" "-a" "ddac7a5a4b426a13808e393d52b10365bf1df3cd5cc46b62bd29b830605cc1b3", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "inspect" "ddac7a5a4b426a13808e393d52b10365bf1df3cd5cc46b62bd29b830605cc1b3", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "ddac7a5a4b426a13808e393d52b10365bf1df3cd5cc46b62bd29b830605cc1b3", kill_on_drop: false }`
[INFO] [stdout] ddac7a5a4b426a13808e393d52b10365bf1df3cd5cc46b62bd29b830605cc1b3
[INFO] running `Command { std: "docker" "create" "-v" "/var/lib/crater-agent-workspace/builds/worker-0-tc2/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-0-tc2/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=warn" "-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" "ghcr.io/rust-lang/crates-build-env/linux@sha256:d429b63d4308055ea97f60fb1d3dfca48854a00942f1bd2ad806beaf015945ec" "/opt/rustwide/cargo-home/bin/cargo" "+beta-2026-04-21" "build" "--frozen" "--message-format=json", kill_on_drop: false }`
[INFO] [stdout] 6717d8045d6498e713aa7591494acd7829081a9af3d541fdba6113b5856bf8f4
[INFO] running `Command { std: "docker" "start" "-a" "6717d8045d6498e713aa7591494acd7829081a9af3d541fdba6113b5856bf8f4", kill_on_drop: false }`
[INFO] [stderr]    Compiling exercises v0.0.0 (/opt/rustwide/workdir)
[INFO] [stdout] error[E0308]: mismatched types
[INFO] [stdout]  --> exercises/09_strings/strings2.rs:9:24
[INFO] [stdout]   |
[INFO] [stdout] 9 |     if is_a_color_word(word) {
[INFO] [stdout]   |        --------------- ^^^^ expected `&str`, found `String`
[INFO] [stdout]   |        |
[INFO] [stdout]   |        arguments to this function are incorrect
[INFO] [stdout]   |
[INFO] [stdout] note: function defined here
[INFO] [stdout]  --> exercises/09_strings/strings2.rs:2:4
[INFO] [stdout]   |
[INFO] [stdout] 2 | fn is_a_color_word(attempt: &str) -> bool {
[INFO] [stdout]   |    ^^^^^^^^^^^^^^^ -------------
[INFO] [stdout] help: consider borrowing here
[INFO] [stdout]   |
[INFO] [stdout] 9 |     if is_a_color_word(&word) {
[INFO] [stdout]   |                        +
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] For more information about this error, try `rustc --explain E0308`.
[INFO] [stdout] 
[INFO] [stderr] error: could not compile `exercises` (bin "strings2") due to 1 previous error
[INFO] [stderr] warning: build failed, waiting for other jobs to finish...
[INFO] [stdout] error[E0061]: this function takes 0 arguments but 1 argument was supplied
[INFO] [stdout]   --> exercises/09_strings/strings4.rs:16:5
[INFO] [stdout]    |
[INFO] [stdout] 16 |     placeholder("blue");
[INFO] [stdout]    |     ^^^^^^^^^^^ ------ unexpected argument of type `&'static str`
[INFO] [stdout]    |
[INFO] [stdout] note: function defined here
[INFO] [stdout]   --> exercises/09_strings/strings4.rs:2:4
[INFO] [stdout]    |
[INFO] [stdout]  2 | fn placeholder() {}
[INFO] [stdout]    |    ^^^^^^^^^^^
[INFO] [stdout] help: remove the extra argument
[INFO] [stdout]    |
[INFO] [stdout] 16 -     placeholder("blue");
[INFO] [stdout] 16 +     placeholder();
[INFO] [stdout]    |
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] error[E0308]: mismatched types
[INFO] [stdout]  --> exercises/18_iterators/iterators4.rs:1:27
[INFO] [stdout]   |
[INFO] [stdout] 1 | fn factorial(num: u64) -> u64 {
[INFO] [stdout]   |    ---------              ^^^ expected `u64`, found `()`
[INFO] [stdout]   |    |
[INFO] [stdout]   |    implicitly returns `()` as its body has no tail or `return` expression
[INFO] [stdout]   |
[INFO] [stdout] help: consider returning the local binding `num`
[INFO] [stdout]   |
[INFO] [stdout] 1 | fn factorial(num: u64) -> u64 {
[INFO] [stdout] 2 ~     num
[INFO] [stdout]   |
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] error[E0061]: this function takes 0 arguments but 1 argument was supplied
[INFO] [stdout]   --> exercises/09_strings/strings4.rs:18:5
[INFO] [stdout]    |
[INFO] [stdout] 18 |     placeholder("red".to_string());
[INFO] [stdout]    |     ^^^^^^^^^^^ ----------------- unexpected argument of type `String`
[INFO] [stdout]    |
[INFO] [stdout] note: function defined here
[INFO] [stdout]   --> exercises/09_strings/strings4.rs:2:4
[INFO] [stdout]    |
[INFO] [stdout]  2 | fn placeholder() {}
[INFO] [stdout]    |    ^^^^^^^^^^^
[INFO] [stdout] help: remove the extra argument
[INFO] [stdout]    |
[INFO] [stdout] 18 -     placeholder("red".to_string());
[INFO] [stdout] 18 +     placeholder();
[INFO] [stdout]    |
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] error[E0061]: this function takes 0 arguments but 1 argument was supplied
[INFO] [stdout]   --> exercises/09_strings/strings4.rs:20:5
[INFO] [stdout]    |
[INFO] [stdout] 20 |     placeholder(String::from("hi"));
[INFO] [stdout]    |     ^^^^^^^^^^^ ------------------ unexpected argument of type `String`
[INFO] [stdout]    |
[INFO] [stdout] note: function defined here
[INFO] [stdout]   --> exercises/09_strings/strings4.rs:2:4
[INFO] [stdout]    |
[INFO] [stdout]  2 | fn placeholder() {}
[INFO] [stdout]    |    ^^^^^^^^^^^
[INFO] [stdout] help: remove the extra argument
[INFO] [stdout]    |
[INFO] [stdout] 20 -     placeholder(String::from("hi"));
[INFO] [stdout] 20 +     placeholder();
[INFO] [stdout]    |
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] error[E0061]: this function takes 0 arguments but 1 argument was supplied
[INFO] [stdout]   --> exercises/09_strings/strings4.rs:22:5
[INFO] [stdout]    |
[INFO] [stdout] 22 |     placeholder("rust is fun!".to_owned());
[INFO] [stdout]    |     ^^^^^^^^^^^ ------------------------- unexpected argument of type `String`
[INFO] [stdout]    |
[INFO] [stdout] note: function defined here
[INFO] [stdout]   --> exercises/09_strings/strings4.rs:2:4
[INFO] [stdout]    |
[INFO] [stdout]  2 | fn placeholder() {}
[INFO] [stdout]    |    ^^^^^^^^^^^
[INFO] [stdout] help: remove the extra argument
[INFO] [stdout]    |
[INFO] [stdout] 22 -     placeholder("rust is fun!".to_owned());
[INFO] [stdout] 22 +     placeholder();
[INFO] [stdout]    |
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] error[E0061]: this function takes 0 arguments but 1 argument was supplied
[INFO] [stdout]   --> exercises/09_strings/strings4.rs:24:5
[INFO] [stdout]    |
[INFO] [stdout] 24 |     placeholder("nice weather".into());
[INFO] [stdout]    |     ^^^^^^^^^^^ --------------------- unexpected argument
[INFO] [stdout]    |
[INFO] [stdout] note: function defined here
[INFO] [stdout]   --> exercises/09_strings/strings4.rs:2:4
[INFO] [stdout]    |
[INFO] [stdout]  2 | fn placeholder() {}
[INFO] [stdout]    |    ^^^^^^^^^^^
[INFO] [stdout] help: remove the extra argument
[INFO] [stdout]    |
[INFO] [stdout] 24 -     placeholder("nice weather".into());
[INFO] [stdout] 24 +     placeholder();
[INFO] [stdout]    |
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] error[E0061]: this function takes 0 arguments but 1 argument was supplied
[INFO] [stdout]   --> exercises/09_strings/strings4.rs:26:5
[INFO] [stdout]    |
[INFO] [stdout] 26 |     placeholder(format!("Interpolation {}", "Station"));
[INFO] [stdout]    |     ^^^^^^^^^^^ -------------------------------------- unexpected argument of type `String`
[INFO] [stdout]    |
[INFO] [stdout] note: function defined here
[INFO] [stdout]   --> exercises/09_strings/strings4.rs:2:4
[INFO] [stdout]    |
[INFO] [stdout]  2 | fn placeholder() {}
[INFO] [stdout]    |    ^^^^^^^^^^^
[INFO] [stdout] help: remove the extra argument
[INFO] [stdout]    |
[INFO] [stdout] 26 -     placeholder(format!("Interpolation {}", "Station"));
[INFO] [stdout] 26 +     placeholder();
[INFO] [stdout]    |
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] error[E0061]: this function takes 0 arguments but 1 argument was supplied
[INFO] [stdout]   --> exercises/09_strings/strings4.rs:30:5
[INFO] [stdout]    |
[INFO] [stdout] 30 |     placeholder(&String::from("abc")[0..1]);
[INFO] [stdout]    |     ^^^^^^^^^^^ -------------------------- unexpected argument of type `&str`
[INFO] [stdout]    |
[INFO] [stdout] note: function defined here
[INFO] [stdout]   --> exercises/09_strings/strings4.rs:2:4
[INFO] [stdout]    |
[INFO] [stdout]  2 | fn placeholder() {}
[INFO] [stdout]    |    ^^^^^^^^^^^
[INFO] [stdout] help: remove the extra argument
[INFO] [stdout]    |
[INFO] [stdout] 30 -     placeholder(&String::from("abc")[0..1]);
[INFO] [stdout] 30 +     placeholder();
[INFO] [stdout]    |
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] error[E0061]: this function takes 0 arguments but 1 argument was supplied
[INFO] [stdout]   --> exercises/09_strings/strings4.rs:32:5
[INFO] [stdout]    |
[INFO] [stdout] 32 |     placeholder("  hello there ".trim());
[INFO] [stdout]    |     ^^^^^^^^^^^ ----------------------- unexpected argument of type `&str`
[INFO] [stdout]    |
[INFO] [stdout] note: function defined here
[INFO] [stdout]   --> exercises/09_strings/strings4.rs:2:4
[INFO] [stdout]    |
[INFO] [stdout]  2 | fn placeholder() {}
[INFO] [stdout]    |    ^^^^^^^^^^^
[INFO] [stdout] help: remove the extra argument
[INFO] [stdout]    |
[INFO] [stdout] 32 -     placeholder("  hello there ".trim());
[INFO] [stdout] 32 +     placeholder();
[INFO] [stdout]    |
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] error[E0061]: this function takes 0 arguments but 1 argument was supplied
[INFO] [stdout]   --> exercises/09_strings/strings4.rs:34:5
[INFO] [stdout]    |
[INFO] [stdout] 34 |     placeholder("Happy Monday!".replace("Mon", "Tues"));
[INFO] [stdout]    |     ^^^^^^^^^^^ -------------------------------------- unexpected argument of type `String`
[INFO] [stdout]    |
[INFO] [stdout] note: function defined here
[INFO] [stdout]   --> exercises/09_strings/strings4.rs:2:4
[INFO] [stdout]    |
[INFO] [stdout]  2 | fn placeholder() {}
[INFO] [stdout]    |    ^^^^^^^^^^^
[INFO] [stdout] help: remove the extra argument
[INFO] [stdout]    |
[INFO] [stdout] 34 -     placeholder("Happy Monday!".replace("Mon", "Tues"));
[INFO] [stdout] 34 +     placeholder();
[INFO] [stdout]    |
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] error[E0061]: this function takes 0 arguments but 1 argument was supplied
[INFO] [stdout]   --> exercises/09_strings/strings4.rs:36:5
[INFO] [stdout]    |
[INFO] [stdout] 36 |     placeholder("mY sHiFt KeY iS sTiCkY".to_lowercase());
[INFO] [stdout]    |     ^^^^^^^^^^^ --------------------------------------- unexpected argument of type `String`
[INFO] [stdout]    |
[INFO] [stdout] note: function defined here
[INFO] [stdout]   --> exercises/09_strings/strings4.rs:2:4
[INFO] [stdout]    |
[INFO] [stdout]  2 | fn placeholder() {}
[INFO] [stdout]    |    ^^^^^^^^^^^
[INFO] [stdout] help: remove the extra argument
[INFO] [stdout]    |
[INFO] [stdout] 36 -     placeholder("mY sHiFt KeY iS sTiCkY".to_lowercase());
[INFO] [stdout] 36 +     placeholder();
[INFO] [stdout]    |
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] For more information about this error, try `rustc --explain E0061`.
[INFO] [stdout] 
[INFO] [stderr] error: could not compile `exercises` (bin "strings4") due to 10 previous errors
[INFO] [stdout] For more information about this error, try `rustc --explain E0308`.
[INFO] [stdout] 
[INFO] [stdout] warning: unreachable expression
[INFO] [stdout]   --> exercises/20_threads/threads2.rs:33:5
[INFO] [stdout]    |
[INFO] [stdout] 33 |     println!("Jobs done: {}", todo!());
[INFO] [stdout]    |     ^^^^^^^^^^^^^^^^^^^^^^^^^^-------^
[INFO] [stdout]    |     |                         |
[INFO] [stdout]    |     |                         any code following this expression is unreachable
[INFO] [stdout]    |     unreachable expression
[INFO] [stdout]    |
[INFO] [stdout]    = note: `#[warn(unreachable_code)]` (part of `#[warn(unused)]`) on by default
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stderr] error: could not compile `exercises` (bin "iterators4") due to 1 previous error
[INFO] [stdout] error[E0594]: cannot assign to data in an `Arc`
[INFO] [stdout]   --> exercises/20_threads/threads2.rs:22:13
[INFO] [stdout]    |
[INFO] [stdout] 22 |             status_shared.jobs_done += 1;
[INFO] [stdout]    |             ^^^^^^^^^^^^^^^^^^^^^^^^^^^^ cannot assign
[INFO] [stdout]    |
[INFO] [stdout]    = help: trait `DerefMut` is required to modify through a dereference, but it is not implemented for `Arc<JobStatus>`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] For more information about this error, try `rustc --explain E0594`.
[INFO] [stdout] 
[INFO] [stderr] error: could not compile `exercises` (bin "threads2") due to 1 previous error; 1 warning emitted
[INFO] running `Command { std: "docker" "inspect" "6717d8045d6498e713aa7591494acd7829081a9af3d541fdba6113b5856bf8f4", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "6717d8045d6498e713aa7591494acd7829081a9af3d541fdba6113b5856bf8f4", kill_on_drop: false }`
[INFO] [stdout] 6717d8045d6498e713aa7591494acd7829081a9af3d541fdba6113b5856bf8f4
