[INFO] cloning repository https://github.com/davetttt/ttt_rust_2
[INFO] running `Command { std: "git" "-c" "credential.helper=" "-c" "credential.helper=/workspace/cargo-home/bin/git-credential-null" "clone" "--bare" "https://github.com/davetttt/ttt_rust_2" "/workspace/cache/git-repos/https%3A%2F%2Fgithub.com%2Fdavetttt%2Fttt_rust_2", kill_on_drop: false }`
[INFO] [stderr] Cloning into bare repository '/workspace/cache/git-repos/https%3A%2F%2Fgithub.com%2Fdavetttt%2Fttt_rust_2'...
[INFO] running `Command { std: "git" "rev-parse" "HEAD", kill_on_drop: false }`
[INFO] [stdout] 44ebdbd5f3afa5acc94ccdcac24f0b487ec608b7
[INFO] testing davetttt/ttt_rust_2 against 1.60.0 for beta-1.61-1
[INFO] running `Command { std: "git" "clone" "/workspace/cache/git-repos/https%3A%2F%2Fgithub.com%2Fdavetttt%2Fttt_rust_2" "/workspace/builds/worker-6/source", kill_on_drop: false }`
[INFO] [stderr] Cloning into '/workspace/builds/worker-6/source'...
[INFO] [stderr] done.
[INFO] validating manifest of git repo https://github.com/davetttt/ttt_rust_2 on toolchain 1.60.0
[INFO] running `Command { std: "/workspace/cargo-home/bin/cargo" "+1.60.0" "metadata" "--manifest-path" "Cargo.toml" "--no-deps", kill_on_drop: false }`
[INFO] started tweaking git repo https://github.com/davetttt/ttt_rust_2
[INFO] finished tweaking git repo https://github.com/davetttt/ttt_rust_2
[INFO] tweaked toml for git repo https://github.com/davetttt/ttt_rust_2 written to /workspace/builds/worker-6/source/Cargo.toml
[INFO] crate git repo https://github.com/davetttt/ttt_rust_2 already has a lockfile, it will not be regenerated
[INFO] running `Command { std: "/workspace/cargo-home/bin/cargo" "+1.60.0" "fetch" "--manifest-path" "Cargo.toml", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "create" "-v" "/var/lib/crater-agent-workspace/builds/worker-6/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-6/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:eaef2f80f755933c374d2ae5edccceec0c1312ceb8a4e0b6404e8ab76561e1e5" "/opt/rustwide/cargo-home/bin/cargo" "+1.60.0" "metadata" "--no-deps" "--format-version=1", kill_on_drop: false }`
[INFO] [stdout] ca7eb988ad4d7ab8df9dbe1adbae515013f7ce9b238080a59641e5e299cfdead
[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" "ca7eb988ad4d7ab8df9dbe1adbae515013f7ce9b238080a59641e5e299cfdead", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "inspect" "ca7eb988ad4d7ab8df9dbe1adbae515013f7ce9b238080a59641e5e299cfdead", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "ca7eb988ad4d7ab8df9dbe1adbae515013f7ce9b238080a59641e5e299cfdead", kill_on_drop: false }`
[INFO] [stdout] ca7eb988ad4d7ab8df9dbe1adbae515013f7ce9b238080a59641e5e299cfdead
[INFO] running `Command { std: "docker" "create" "-v" "/var/lib/crater-agent-workspace/builds/worker-6/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-6/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" "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:eaef2f80f755933c374d2ae5edccceec0c1312ceb8a4e0b6404e8ab76561e1e5" "/opt/rustwide/cargo-home/bin/cargo" "+1.60.0" "build" "--frozen" "--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] 65c7f5e615025fa8227945a6081c68d90d75d85b0d14d6adb0c8d2f7c1db14d4
[INFO] running `Command { std: "docker" "start" "-a" "65c7f5e615025fa8227945a6081c68d90d75d85b0d14d6adb0c8d2f7c1db14d4", kill_on_drop: false }`
[INFO] [stderr]    Compiling ttt_rust_2 v0.0.1 (/opt/rustwide/workdir)
[INFO] [stdout] warning: unknown lint: `unstable`
[INFO] [stdout]  --> src/main.rs:1:10
[INFO] [stdout]   |
[INFO] [stdout] 1 | #![allow(unstable)]
[INFO] [stdout]   |          ^^^^^^^^
[INFO] [stdout]   |
[INFO] [stdout]   = note: `#[warn(unknown_lints)]` on by default
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] error[E0432]: unresolved import `std::num::Float`
[INFO] [stdout]  --> src/board.rs:2:5
[INFO] [stdout]   |
[INFO] [stdout] 2 | use std::num::Float;
[INFO] [stdout]   |     ^^^^^^^^^^^^^^^ no `Float` in `num`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] error[E0432]: unresolved import `std::io::BufferedReader`
[INFO] [stdout]  --> src/io.rs:2:5
[INFO] [stdout]   |
[INFO] [stdout] 2 | use std::io::BufferedReader;
[INFO] [stdout]   |     ^^^^^^^^^^^^^^^^^^^^^^^ no `BufferedReader` in `io`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] error: cannot find derive macro `Show` in this scope
[INFO] [stdout]  --> src/token.rs:1:21
[INFO] [stdout]   |
[INFO] [stdout] 1 | #[derive(PartialEq, Show)] // so that tokens can be compared
[INFO] [stdout]   |                     ^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] error[E0425]: cannot find function `range` in this scope
[INFO] [stdout]  --> src/board.rs:7:14
[INFO] [stdout]   |
[INFO] [stdout] 7 |     for i in range(0, width * width) {
[INFO] [stdout]   |              ^^^^^ not found in this scope
[INFO] [stdout]   |
[INFO] [stdout] help: consider importing this function
[INFO] [stdout]   |
[INFO] [stdout] 1 | use std::slice::range;
[INFO] [stdout]   |
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] error[E0425]: cannot find function `range` in this scope
[INFO] [stdout]   --> src/board.rs:32:25
[INFO] [stdout]    |
[INFO] [stdout] 32 |     let space_numbers = range(0, board.len()).
[INFO] [stdout]    |                         ^^^^^ not found in this scope
[INFO] [stdout]    |
[INFO] [stdout] help: consider importing this function
[INFO] [stdout]    |
[INFO] [stdout] 1  | use std::slice::range;
[INFO] [stdout]    |
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] error[E0425]: cannot find function `range` in this scope
[INFO] [stdout]   --> src/board.rs:42:23
[INFO] [stdout]    |
[INFO] [stdout] 42 |     for row_number in range(0, width) {
[INFO] [stdout]    |                       ^^^^^ not found in this scope
[INFO] [stdout]    |
[INFO] [stdout] help: consider importing this function
[INFO] [stdout]    |
[INFO] [stdout] 1  | use std::slice::range;
[INFO] [stdout]    |
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] error[E0425]: cannot find function `range` in this scope
[INFO] [stdout]   --> src/board.rs:52:26
[INFO] [stdout]    |
[INFO] [stdout] 52 |     for column_number in range(0, width) {
[INFO] [stdout]    |                          ^^^^^ not found in this scope
[INFO] [stdout]    |
[INFO] [stdout] help: consider importing this function
[INFO] [stdout]    |
[INFO] [stdout] 1  | use std::slice::range;
[INFO] [stdout]    |
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] error[E0425]: cannot find function `range` in this scope
[INFO] [stdout]   --> src/board.rs:83:5
[INFO] [stdout]    |
[INFO] [stdout] 83 |     range(0, board.len()).
[INFO] [stdout]    |     ^^^^^ not found in this scope
[INFO] [stdout]    |
[INFO] [stdout] help: consider importing this function
[INFO] [stdout]    |
[INFO] [stdout] 1  | use std::slice::range;
[INFO] [stdout]    |
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] error[E0425]: cannot find function `range` in this scope
[INFO] [stdout]   --> src/io.rs:60:18
[INFO] [stdout]    |
[INFO] [stdout] 60 |         for i in range(0, row.len()) {
[INFO] [stdout]    |                  ^^^^^ not found in this scope
[INFO] [stdout]    |
[INFO] [stdout] help: consider importing this function
[INFO] [stdout]    |
[INFO] [stdout] 1  | use std::slice::range;
[INFO] [stdout]    |
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] error[E0425]: cannot find function `range` in this scope
[INFO] [stdout]   --> src/io.rs:87:27
[INFO] [stdout]    |
[INFO] [stdout] 87 |         for row_number in range(0, rows.len()) {
[INFO] [stdout]    |                           ^^^^^ not found in this scope
[INFO] [stdout]    |
[INFO] [stdout] help: consider importing this function
[INFO] [stdout]    |
[INFO] [stdout] 1  | use std::slice::range;
[INFO] [stdout]    |
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: trait objects without an explicit `dyn` are deprecated
[INFO] [stdout]  --> src/game.rs:6:36
[INFO] [stdout]   |
[INFO] [stdout] 6 | pub fn game_loop(players: &Vec<Box<player::Player>>,
[INFO] [stdout]   |                                    ^^^^^^^^^^^^^^
[INFO] [stdout]   |
[INFO] [stdout]   = note: `#[warn(bare_trait_objects)]` on by default
[INFO] [stdout]   = warning: this is accepted in the current edition (Rust 2015) but is a hard error in Rust 2021!
[INFO] [stdout]   = note: for more information, see <https://doc.rust-lang.org/nightly/edition-guide/rust-2021/warnings-promoted-to-error.html>
[INFO] [stdout] help: use `dyn`
[INFO] [stdout]   |
[INFO] [stdout] 6 - pub fn game_loop(players: &Vec<Box<player::Player>>,
[INFO] [stdout] 6 + pub fn game_loop(players: &Vec<Box<dyn player::Player>>,
[INFO] [stdout]   | 
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: trait objects without an explicit `dyn` are deprecated
[INFO] [stdout]   --> src/game.rs:24:43
[INFO] [stdout]    |
[INFO] [stdout] 24 | pub fn play_game<I: Io>(players: &Vec<Box<player::Player>>,
[INFO] [stdout]    |                                           ^^^^^^^^^^^^^^
[INFO] [stdout]    |
[INFO] [stdout]    = warning: this is accepted in the current edition (Rust 2015) but is a hard error in Rust 2021!
[INFO] [stdout]    = note: for more information, see <https://doc.rust-lang.org/nightly/edition-guide/rust-2021/warnings-promoted-to-error.html>
[INFO] [stdout] help: use `dyn`
[INFO] [stdout]    |
[INFO] [stdout] 24 - pub fn play_game<I: Io>(players: &Vec<Box<player::Player>>,
[INFO] [stdout] 24 + pub fn play_game<I: Io>(players: &Vec<Box<dyn player::Player>>,
[INFO] [stdout]    | 
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: trait objects without an explicit `dyn` are deprecated
[INFO] [stdout]  --> src/config.rs:5:31
[INFO] [stdout]   |
[INFO] [stdout] 5 | fn human_cpu<'a>() -> Vec<Box<Player + 'a>> {
[INFO] [stdout]   |                               ^^^^^^^^^^^
[INFO] [stdout]   |
[INFO] [stdout]   = warning: this is accepted in the current edition (Rust 2015) but is a hard error in Rust 2021!
[INFO] [stdout]   = note: for more information, see <https://doc.rust-lang.org/nightly/edition-guide/rust-2021/warnings-promoted-to-error.html>
[INFO] [stdout] help: use `dyn`
[INFO] [stdout]   |
[INFO] [stdout] 5 - fn human_cpu<'a>() -> Vec<Box<Player + 'a>> {
[INFO] [stdout] 5 + fn human_cpu<'a>() -> Vec<Box<dyn Player + 'a>> {
[INFO] [stdout]   | 
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: trait objects without an explicit `dyn` are deprecated
[INFO] [stdout]   --> src/config.rs:12:31
[INFO] [stdout]    |
[INFO] [stdout] 12 | fn cpu_human<'a>() -> Vec<Box<Player + 'a>> {
[INFO] [stdout]    |                               ^^^^^^^^^^^
[INFO] [stdout]    |
[INFO] [stdout]    = warning: this is accepted in the current edition (Rust 2015) but is a hard error in Rust 2021!
[INFO] [stdout]    = note: for more information, see <https://doc.rust-lang.org/nightly/edition-guide/rust-2021/warnings-promoted-to-error.html>
[INFO] [stdout] help: use `dyn`
[INFO] [stdout]    |
[INFO] [stdout] 12 - fn cpu_human<'a>() -> Vec<Box<Player + 'a>> {
[INFO] [stdout] 12 + fn cpu_human<'a>() -> Vec<Box<dyn Player + 'a>> {
[INFO] [stdout]    | 
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: trait objects without an explicit `dyn` are deprecated
[INFO] [stdout]   --> src/config.rs:19:33
[INFO] [stdout]    |
[INFO] [stdout] 19 | fn human_human<'a>() -> Vec<Box<Player + 'a>> {
[INFO] [stdout]    |                                 ^^^^^^^^^^^
[INFO] [stdout]    |
[INFO] [stdout]    = warning: this is accepted in the current edition (Rust 2015) but is a hard error in Rust 2021!
[INFO] [stdout]    = note: for more information, see <https://doc.rust-lang.org/nightly/edition-guide/rust-2021/warnings-promoted-to-error.html>
[INFO] [stdout] help: use `dyn`
[INFO] [stdout]    |
[INFO] [stdout] 19 - fn human_human<'a>() -> Vec<Box<Player + 'a>> {
[INFO] [stdout] 19 + fn human_human<'a>() -> Vec<Box<dyn Player + 'a>> {
[INFO] [stdout]    | 
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: trait objects without an explicit `dyn` are deprecated
[INFO] [stdout]   --> src/config.rs:26:56
[INFO] [stdout]    |
[INFO] [stdout] 26 | pub fn configure_players<'a, I: Io>(io: &I) -> Vec<Box<Player + 'a>> {
[INFO] [stdout]    |                                                        ^^^^^^^^^^^
[INFO] [stdout]    |
[INFO] [stdout]    = warning: this is accepted in the current edition (Rust 2015) but is a hard error in Rust 2021!
[INFO] [stdout]    = note: for more information, see <https://doc.rust-lang.org/nightly/edition-guide/rust-2021/warnings-promoted-to-error.html>
[INFO] [stdout] help: use `dyn`
[INFO] [stdout]    |
[INFO] [stdout] 26 - pub fn configure_players<'a, I: Io>(io: &I) -> Vec<Box<Player + 'a>> {
[INFO] [stdout] 26 + pub fn configure_players<'a, I: Io>(io: &I) -> Vec<Box<dyn Player + 'a>> {
[INFO] [stdout]    | 
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] error[E0599]: no method named `as_slice` found for struct `String` in the current scope
[INFO] [stdout]   --> src/io.rs:62:69
[INFO] [stdout]    |
[INFO] [stdout] 62 |             result.push_str(self.format_space(row[i], space_number).as_slice());
[INFO] [stdout]    |                                                                     ^^^^^^^^ method not found in `String`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] error[E0599]: no method named `as_slice` found for reference `&&str` in the current scope
[INFO] [stdout]   --> src/io.rs:77:44
[INFO] [stdout]    |
[INFO] [stdout] 77 |                   position(|option| option.as_slice() == answer.trim()) {
[INFO] [stdout]    |                                            ^^^^^^^^ method not found in `&&str`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] error[E0599]: no method named `as_slice` found for struct `String` in the current scope
[INFO] [stdout]   --> src/io.rs:90:59
[INFO] [stdout]    |
[INFO] [stdout] 90 | ...                   row_number * board_width).as_slice());
[INFO] [stdout]    |                                                 ^^^^^^^^ method not found in `String`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] error[E0599]: no method named `as_slice` found for struct `String` in the current scope
[INFO] [stdout]   --> src/io.rs:92:29
[INFO] [stdout]    |
[INFO] [stdout] 92 |         print!("{}", result.as_slice())
[INFO] [stdout]    |                             ^^^^^^^^ method not found in `String`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] error[E0599]: no method named `as_slice` found for reference `&String` in the current scope
[INFO] [stdout]   --> src/player.rs:31:60
[INFO] [stdout]    |
[INFO] [stdout] 31 |         let options = empty_space_strings.iter().map(|s| s.as_slice()).collect();
[INFO] [stdout]    |                                                            ^^^^^^^^ method not found in `&String`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] error[E0599]: no method named `push_all` found for struct `Vec<Vec<Token>>` in the current scope
[INFO] [stdout]   --> src/rules.rs:14:11
[INFO] [stdout]    |
[INFO] [stdout] 14 |     lines.push_all(board::get_columns(board).as_slice());
[INFO] [stdout]    |           ^^^^^^^^ method not found in `Vec<Vec<Token>>`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] error[E0599]: no method named `push_all` found for struct `Vec<Vec<Token>>` in the current scope
[INFO] [stdout]   --> src/rules.rs:15:11
[INFO] [stdout]    |
[INFO] [stdout] 15 |     lines.push_all(board::get_diagonals(board).as_slice());
[INFO] [stdout]    |           ^^^^^^^^ method not found in `Vec<Vec<Token>>`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] error[E0593]: closure is expected to take 2 arguments, but it takes 1 argument
[INFO] [stdout]   --> src/minimax.rs:37:29
[INFO] [stdout]    |
[INFO] [stdout] 37 | ...                   max_by(|tuple| tuple.1).unwrap(),
[INFO] [stdout]    |                       ^^^^^^ ------- takes 1 argument
[INFO] [stdout]    |                       |
[INFO] [stdout]    |                       expected closure that takes 2 arguments
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] error[E0593]: closure is expected to take 2 arguments, but it takes 1 argument
[INFO] [stdout]   --> src/minimax.rs:39:29
[INFO] [stdout]    |
[INFO] [stdout] 39 | ...                   min_by(|tuple| tuple.1).unwrap(),
[INFO] [stdout]    |                       ^^^^^^ ------- takes 1 argument
[INFO] [stdout]    |                       |
[INFO] [stdout]    |                       expected closure that takes 2 arguments
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: trait objects without an explicit `dyn` are deprecated
[INFO] [stdout]  --> src/config.rs:6:30
[INFO] [stdout]   |
[INFO] [stdout] 6 |     let mut players: Vec<Box<Player>> = Vec::new();
[INFO] [stdout]   |                              ^^^^^^
[INFO] [stdout]   |
[INFO] [stdout]   = warning: this is accepted in the current edition (Rust 2015) but is a hard error in Rust 2021!
[INFO] [stdout]   = note: for more information, see <https://doc.rust-lang.org/nightly/edition-guide/rust-2021/warnings-promoted-to-error.html>
[INFO] [stdout] help: use `dyn`
[INFO] [stdout]   |
[INFO] [stdout] 6 -     let mut players: Vec<Box<Player>> = Vec::new();
[INFO] [stdout] 6 +     let mut players: Vec<Box<dyn Player>> = Vec::new();
[INFO] [stdout]   | 
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: trait objects without an explicit `dyn` are deprecated
[INFO] [stdout]   --> src/config.rs:13:30
[INFO] [stdout]    |
[INFO] [stdout] 13 |     let mut players: Vec<Box<Player>> = Vec::new();
[INFO] [stdout]    |                              ^^^^^^
[INFO] [stdout]    |
[INFO] [stdout]    = warning: this is accepted in the current edition (Rust 2015) but is a hard error in Rust 2021!
[INFO] [stdout]    = note: for more information, see <https://doc.rust-lang.org/nightly/edition-guide/rust-2021/warnings-promoted-to-error.html>
[INFO] [stdout] help: use `dyn`
[INFO] [stdout]    |
[INFO] [stdout] 13 -     let mut players: Vec<Box<Player>> = Vec::new();
[INFO] [stdout] 13 +     let mut players: Vec<Box<dyn Player>> = Vec::new();
[INFO] [stdout]    | 
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: trait objects without an explicit `dyn` are deprecated
[INFO] [stdout]   --> src/config.rs:20:30
[INFO] [stdout]    |
[INFO] [stdout] 20 |     let mut players: Vec<Box<Player>> = Vec::new();
[INFO] [stdout]    |                              ^^^^^^
[INFO] [stdout]    |
[INFO] [stdout]    = warning: this is accepted in the current edition (Rust 2015) but is a hard error in Rust 2021!
[INFO] [stdout]    = note: for more information, see <https://doc.rust-lang.org/nightly/edition-guide/rust-2021/warnings-promoted-to-error.html>
[INFO] [stdout] help: use `dyn`
[INFO] [stdout]    |
[INFO] [stdout] 20 -     let mut players: Vec<Box<Player>> = Vec::new();
[INFO] [stdout] 20 +     let mut players: Vec<Box<dyn Player>> = Vec::new();
[INFO] [stdout]    | 
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] error: aborting due to 19 previous errors; 10 warnings emitted
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] Some errors have detailed explanations: E0425, E0432, E0593, E0599.
[INFO] [stdout] 
[INFO] [stdout] For more information about an error, try `rustc --explain E0425`.
[INFO] [stdout] 
[INFO] [stderr] error: could not compile `ttt_rust_2` due to 20 previous errors; 10 warnings emitted
[INFO] running `Command { std: "docker" "inspect" "65c7f5e615025fa8227945a6081c68d90d75d85b0d14d6adb0c8d2f7c1db14d4", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "65c7f5e615025fa8227945a6081c68d90d75d85b0d14d6adb0c8d2f7c1db14d4", kill_on_drop: false }`
[INFO] [stdout] 65c7f5e615025fa8227945a6081c68d90d75d85b0d14d6adb0c8d2f7c1db14d4