[INFO] cloning repository https://github.com/leecobaby/study-rust
[INFO] running `Command { std: "git" "-c" "credential.helper=" "-c" "credential.helper=/workspace/cargo-home/bin/git-credential-null" "clone" "--bare" "https://github.com/leecobaby/study-rust" "/workspace/cache/git-repos/https%3A%2F%2Fgithub.com%2Fleecobaby%2Fstudy-rust", kill_on_drop: false }`
[INFO] [stderr] Cloning into bare repository '/workspace/cache/git-repos/https%3A%2F%2Fgithub.com%2Fleecobaby%2Fstudy-rust'...
[INFO] running `Command { std: "git" "rev-parse" "HEAD", kill_on_drop: false }`
[INFO] [stdout] d7cb5e178d0d2d6794201af8b33d067ab635bef3
[INFO] testing leecobaby/study-rust 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%2Fleecobaby%2Fstudy-rust" "/workspace/builds/worker-4-tc2/source", kill_on_drop: false }`
[INFO] [stderr] Cloning into '/workspace/builds/worker-4-tc2/source'...
[INFO] [stderr] done.
[INFO] started tweaking git repo https://github.com/leecobaby/study-rust
[INFO] finished tweaking git repo https://github.com/leecobaby/study-rust
[INFO] tweaked toml for git repo https://github.com/leecobaby/study-rust written to /workspace/builds/worker-4-tc2/source/Cargo.toml
[INFO] validating manifest of git repo https://github.com/leecobaby/study-rust 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/leecobaby/study-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" "+beta-2026-04-21" "fetch" "--manifest-path" "Cargo.toml", kill_on_drop: false }`
[INFO] [stderr] warning: unused manifest key: profiles
[INFO] running `Command { std: "docker" "create" "-v" "/var/lib/crater-agent-workspace/builds/worker-4-tc2/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-4-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] c20323702e0b67c81e30d29fcaa5f276280c4f50071eda4194b50d5a4745d7f5
[INFO] running `Command { std: "docker" "start" "-a" "c20323702e0b67c81e30d29fcaa5f276280c4f50071eda4194b50d5a4745d7f5", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "inspect" "c20323702e0b67c81e30d29fcaa5f276280c4f50071eda4194b50d5a4745d7f5", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "c20323702e0b67c81e30d29fcaa5f276280c4f50071eda4194b50d5a4745d7f5", kill_on_drop: false }`
[INFO] [stdout] c20323702e0b67c81e30d29fcaa5f276280c4f50071eda4194b50d5a4745d7f5
[INFO] running `Command { std: "docker" "create" "-v" "/var/lib/crater-agent-workspace/builds/worker-4-tc2/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-4-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] 3d68eef1d1bea126a0fa3058a291bd534ec4cb9863244acf7c59c80b36c4d4d4
[INFO] running `Command { std: "docker" "start" "-a" "3d68eef1d1bea126a0fa3058a291bd534ec4cb9863244acf7c59c80b36c4d4d4", kill_on_drop: false }`
[INFO] [stderr] warning: unused manifest key: profiles
[INFO] [stderr]    Compiling rand_core v0.3.1
[INFO] [stderr]    Compiling rand v0.5.6
[INFO] [stderr]    Compiling study_rust v0.1.0 (/opt/rustwide/workdir)
[INFO] [stdout] warning: unused variable: `b`
[INFO] [stdout]   --> src/bin/15-4.rs:21:9
[INFO] [stdout]    |
[INFO] [stdout] 21 |     let b = Cons(3, Rc::clone(&a));
[INFO] [stdout]    |         ^ help: if this is intentional, prefix it with an underscore: `_b`
[INFO] [stdout]    |
[INFO] [stdout]    = note: `#[warn(unused_variables)]` (part of `#[warn(unused)]`) on by default
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `c`
[INFO] [stdout]   --> src/bin/15-4.rs:24:13
[INFO] [stdout]    |
[INFO] [stdout] 24 |         let c = Cons(4, Rc::clone(&a));
[INFO] [stdout]    |             ^ help: if this is intentional, prefix it with an underscore: `_c`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: fields `0` and `1` are never read
[INFO] [stdout]   --> src/bin/15-4.rs:11:10
[INFO] [stdout]    |
[INFO] [stdout] 11 |     Cons(i32, Rc<List>),
[INFO] [stdout]    |     ---- ^^^  ^^^^^^^^
[INFO] [stdout]    |     |
[INFO] [stdout]    |     fields in this variant
[INFO] [stdout]    |
[INFO] [stdout]    = note: `#[warn(dead_code)]` (part of `#[warn(unused)]`) on by default
[INFO] [stdout] help: consider changing the fields to be of unit type to suppress this warning while preserving the field numbering, or remove the fields
[INFO] [stdout]    |
[INFO] [stdout] 11 -     Cons(i32, Rc<List>),
[INFO] [stdout] 11 +     Cons((), ()),
[INFO] [stdout]    |
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] error[E0601]: `main` function not found in crate `11_8`
[INFO] [stdout]   --> src/bin/11-8.rs:19:2
[INFO] [stdout]    |
[INFO] [stdout] 19 | }
[INFO] [stdout]    |  ^ consider adding a `main` function to `src/bin/11-8.rs`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] For more information about this error, try `rustc --explain E0601`.
[INFO] [stdout] 
[INFO] [stdout] error[E0601]: `main` function not found in crate `18_1`
[INFO] [stdout]  --> src/bin/18-1.rs:6:10
[INFO] [stdout]   |
[INFO] [stdout] 6 | // param
[INFO] [stdout]   |         ^ consider adding a `main` function to `src/bin/18-1.rs`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stderr] error: could not compile `study_rust` (bin "11-8") due to 1 previous error
[INFO] [stdout] For more information about this error, try `rustc --explain E0601`.
[INFO] [stdout] 
[INFO] [stderr] warning: build failed, waiting for other jobs to finish...
[INFO] [stdout] error[E0601]: `main` function not found in crate `14_6`
[INFO] [stdout]   --> src/bin/14-6.rs:10:76
[INFO] [stdout]    |
[INFO] [stdout] 10 | // 如果 $HOME/.cargo/bin 在 $PATH 中，有个二进制文件叫做 cargo-xxx，那么就可以通过 cargo xxx 来运行它
[INFO] [stdout]    |                                                                                                      ^ consider adding a `main` function to `src/bin/14-6.rs`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stderr] error: could not compile `study_rust` (bin "18-1") due to 1 previous error
[INFO] [stdout] For more information about this error, try `rustc --explain E0601`.
[INFO] [stdout] 
[INFO] [stdout] error[E0106]: missing lifetime specifier
[INFO] [stdout]   --> src/bin/4-2.rs:30:16
[INFO] [stdout]    |
[INFO] [stdout] 30 | fn dangle() -> &String { // 编译器会报错
[INFO] [stdout]    |                ^ expected named lifetime parameter
[INFO] [stdout]    |
[INFO] [stdout]    = help: this function's return type contains a borrowed value, but there is no value for it to be borrowed from
[INFO] [stdout] help: consider using the `'static` lifetime, but this is uncommon unless you're returning a borrowed value from a `const` or a `static`
[INFO] [stdout]    |
[INFO] [stdout] 30 | fn dangle() -> &'static String { // 编译器会报错
[INFO] [stdout]    |                 +++++++
[INFO] [stdout] help: instead, you are more likely to want to return an owned value
[INFO] [stdout]    |
[INFO] [stdout] 30 - fn dangle() -> &String { // 编译器会报错
[INFO] [stdout] 30 + fn dangle() -> String { // 编译器会报错
[INFO] [stdout]    |
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stderr] error: could not compile `study_rust` (bin "14-6") due to 1 previous error
[INFO] [stdout] error[E0601]: `main` function not found in crate `16_4`
[INFO] [stdout]  --> src/bin/16-4.rs:7:41
[INFO] [stdout]   |
[INFO] [stdout] 7 | // 也就是说，如果一个类型 T 实现了 Sync，那么 &T 就是 Send
[INFO] [stdout]   |                                                           ^ consider adding a `main` function to `src/bin/16-4.rs`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] error[E0601]: `main` function not found in crate `11_6`
[INFO] [stdout]   --> src/bin/11-6.rs:34:2
[INFO] [stdout]    |
[INFO] [stdout] 34 | }
[INFO] [stdout]    |  ^ consider adding a `main` function to `src/bin/11-6.rs`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] For more information about this error, try `rustc --explain E0106`.
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `s1`
[INFO] [stdout]  --> src/bin/8-4.rs:2:9
[INFO] [stdout]   |
[INFO] [stdout] 2 |     let s1 = String::from("hello");
[INFO] [stdout]   |         ^^ help: if this is intentional, prefix it with an underscore: `_s1`
[INFO] [stdout]   |
[INFO] [stdout]   = note: `#[warn(unused_variables)]` (part of `#[warn(unused)]`) on by default
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] For more information about this error, try `rustc --explain E0601`.
[INFO] [stdout] 
[INFO] [stderr] error: could not compile `study_rust` (bin "16-4") due to 1 previous error
[INFO] [stderr] error: could not compile `study_rust` (bin "4-2") due to 1 previous error
[INFO] [stdout] warning: unused variable: `v`
[INFO] [stdout]   --> src/bin/19-4.rs:22:9
[INFO] [stdout]    |
[INFO] [stdout] 22 |     let v = Status::Value(3);
[INFO] [stdout]    |         ^ help: if this is intentional, prefix it with an underscore: `_v`
[INFO] [stdout]    |
[INFO] [stdout]    = note: `#[warn(unused_variables)]` (part of `#[warn(unused)]`) on by default
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `list_of_statuses`
[INFO] [stdout]   --> src/bin/19-4.rs:24:9
[INFO] [stdout]    |
[INFO] [stdout] 24 |     let list_of_statuses: Vec<Status> = (0u32..20).map(Status::Value).collect();
[INFO] [stdout]    |         ^^^^^^^^^^^^^^^^ help: if this is intentional, prefix it with an underscore: `_list_of_statuses`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] For more information about this error, try `rustc --explain E0601`.
[INFO] [stdout] 
[INFO] [stdout] warning: field `0` is never read
[INFO] [stdout]   --> src/bin/19-4.rs:17:15
[INFO] [stdout]    |
[INFO] [stdout] 17 |         Value(u32),
[INFO] [stdout]    |         ----- ^^^
[INFO] [stdout]    |         |
[INFO] [stdout]    |         field in this variant
[INFO] [stdout]    |
[INFO] [stdout]    = note: `#[warn(dead_code)]` (part of `#[warn(unused)]`) on by default
[INFO] [stdout] help: consider changing the field to be of unit type to suppress this warning while preserving the field numbering, or remove the field
[INFO] [stdout]    |
[INFO] [stdout] 17 -         Value(u32),
[INFO] [stdout] 17 +         Value(()),
[INFO] [stdout]    |
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `i`
[INFO] [stdout]   --> src/bin/10-8.rs:25:9
[INFO] [stdout]    |
[INFO] [stdout] 25 |     let i = ImportantExcerpt {
[INFO] [stdout]    |         ^ help: if this is intentional, prefix it with an underscore: `_i`
[INFO] [stdout]    |
[INFO] [stdout]    = note: `#[warn(unused_variables)]` (part of `#[warn(unused)]`) on by default
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: field `part` is never read
[INFO] [stdout]  --> src/bin/10-8.rs:6:5
[INFO] [stdout]   |
[INFO] [stdout] 5 | struct ImportantExcerpt<'a> {
[INFO] [stdout]   |        ---------------- field in this struct
[INFO] [stdout] 6 |     part: &'a str,
[INFO] [stdout]   |     ^^^^
[INFO] [stdout]   |
[INFO] [stdout]   = note: `#[warn(dead_code)]` (part of `#[warn(unused)]`) on by default
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: methods `level` and `announce_and_return_part` are never used
[INFO] [stdout]   --> src/bin/10-8.rs:10:8
[INFO] [stdout]    |
[INFO] [stdout]  9 | impl<'a> ImportantExcerpt<'a> {
[INFO] [stdout]    | ----------------------------- methods in this implementation
[INFO] [stdout] 10 |     fn level(&self) -> i32 {
[INFO] [stdout]    |        ^^^^^
[INFO] [stdout] ...
[INFO] [stdout] 16 |     fn announce_and_return_part(&self, announcement: &str) -> &str {
[INFO] [stdout]    |        ^^^^^^^^^^^^^^^^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: variant `Stop` is never constructed
[INFO] [stdout]   --> src/bin/19-4.rs:18:9
[INFO] [stdout]    |
[INFO] [stdout] 16 |     enum Status {
[INFO] [stdout]    |          ------ variant in this enum
[INFO] [stdout] 17 |         Value(u32),
[INFO] [stdout] 18 |         Stop,
[INFO] [stdout]    |         ^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: function `returns_closure` is never used
[INFO] [stdout]   --> src/bin/19-4.rs:39:4
[INFO] [stdout]    |
[INFO] [stdout] 39 | fn returns_closure() -> Box<dyn Fn(i32) -> i32> {
[INFO] [stdout]    |    ^^^^^^^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: function `longest_with_an_announcement` is never used
[INFO] [stdout]   --> src/bin/10-8.rs:34:4
[INFO] [stdout]    |
[INFO] [stdout] 34 | fn longest_with_an_announcement<'a, T>(x: &'a str, y: &'a str, ann: T) -> &'a str
[INFO] [stdout]    |    ^^^^^^^^^^^^^^^^^^^^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] error[E0502]: cannot borrow `s` as mutable because it is also borrowed as immutable
[INFO] [stdout]  --> src/bin/4-3.rs:6:5
[INFO] [stdout]   |
[INFO] [stdout] 4 |     let word_slice = first_word_slice(&s);
[INFO] [stdout]   |                                       -- immutable borrow occurs here
[INFO] [stdout] 5 |
[INFO] [stdout] 6 |     s.clear(); // 这清空了字符串，使其等于 ""
[INFO] [stdout]   |     ^^^^^^^^^ mutable borrow occurs here
[INFO] [stdout] 7 |     println!("The first word is: {}", word_slice);
[INFO] [stdout]   |                                       ---------- immutable borrow later used here
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `word_index`
[INFO] [stdout]  --> src/bin/4-3.rs:3:9
[INFO] [stdout]   |
[INFO] [stdout] 3 |     let word_index = first_word(&s);
[INFO] [stdout]   |         ^^^^^^^^^^ help: if this is intentional, prefix it with an underscore: `_word_index`
[INFO] [stdout]   |
[INFO] [stdout]   = note: `#[warn(unused_variables)]` (part of `#[warn(unused)]`) on by default
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `whole`
[INFO] [stdout]   --> src/bin/4-3.rs:14:9
[INFO] [stdout]    |
[INFO] [stdout] 14 |     let whole = &s1[..];
[INFO] [stdout]    |         ^^^^^ help: if this is intentional, prefix it with an underscore: `_whole`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `slice`
[INFO] [stdout]   --> src/bin/4-3.rs:22:9
[INFO] [stdout]    |
[INFO] [stdout] 22 |     let slice = &a[1..3];
[INFO] [stdout]    |         ^^^^^ help: if this is intentional, prefix it with an underscore: `_slice`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] For more information about this error, try `rustc --explain E0502`.
[INFO] [stdout] 
[INFO] [stderr] error: could not compile `study_rust` (bin "11-6") due to 1 previous error
[INFO] [stderr] error: could not compile `study_rust` (bin "4-3") due to 1 previous error; 3 warnings emitted
[INFO] running `Command { std: "docker" "inspect" "3d68eef1d1bea126a0fa3058a291bd534ec4cb9863244acf7c59c80b36c4d4d4", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "3d68eef1d1bea126a0fa3058a291bd534ec4cb9863244acf7c59c80b36c4d4d4", kill_on_drop: false }`
[INFO] [stdout] 3d68eef1d1bea126a0fa3058a291bd534ec4cb9863244acf7c59c80b36c4d4d4
