[INFO] cloning repository https://github.com/letaron/tacron
[INFO] running `Command { std: "git" "-c" "credential.helper=" "-c" "credential.helper=/workspace/cargo-home/bin/git-credential-null" "clone" "--bare" "https://github.com/letaron/tacron" "/workspace/cache/git-repos/https%3A%2F%2Fgithub.com%2Fletaron%2Ftacron", kill_on_drop: false }`
[INFO] [stderr] Cloning into bare repository '/workspace/cache/git-repos/https%3A%2F%2Fgithub.com%2Fletaron%2Ftacron'...
[INFO] running `Command { std: "git" "rev-parse" "HEAD", kill_on_drop: false }`
[INFO] [stdout] 80c7a770b45d2f7d5d177182307f193b17a16c6f
[INFO] checking letaron/tacron against master#385fa9d845dd326c6bbfd58c22244215e431948a for absurd-question-mark-desugar
[INFO] running `Command { std: "git" "clone" "/workspace/cache/git-repos/https%3A%2F%2Fgithub.com%2Fletaron%2Ftacron" "/workspace/builds/worker-7-tc1/source", kill_on_drop: false }`
[INFO] [stderr] Cloning into '/workspace/builds/worker-7-tc1/source'...
[INFO] [stderr] done.
[INFO] validating manifest of git repo https://github.com/letaron/tacron on toolchain 385fa9d845dd326c6bbfd58c22244215e431948a
[INFO] running `Command { std: CARGO_HOME="/workspace/cargo-home" RUSTUP_HOME="/workspace/rustup-home" "/workspace/cargo-home/bin/cargo" "+385fa9d845dd326c6bbfd58c22244215e431948a" "metadata" "--manifest-path" "Cargo.toml" "--no-deps", kill_on_drop: false }`
[INFO] started tweaking git repo https://github.com/letaron/tacron
[INFO] finished tweaking git repo https://github.com/letaron/tacron
[INFO] tweaked toml for git repo https://github.com/letaron/tacron written to /workspace/builds/worker-7-tc1/source/Cargo.toml
[INFO] crate git repo https://github.com/letaron/tacron 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" "+385fa9d845dd326c6bbfd58c22244215e431948a" "fetch" "--manifest-path" "Cargo.toml", kill_on_drop: false }`
[INFO] [stderr]  Downloading crates ...
[INFO] [stderr]   Downloaded signal-hook v0.1.8
[INFO] [stderr]   Downloaded arc-swap v0.3.7
[INFO] [stderr]   Downloaded libc v0.2.49
[INFO] running `Command { std: "docker" "create" "-v" "/var/lib/crater-agent-workspace/builds/worker-7-tc1/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-7-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@sha256:2788e3201cd34a07e3172128adcd8b3090168a8e3bcc40d7c032b9dda1df7d1c" "/opt/rustwide/cargo-home/bin/cargo" "+385fa9d845dd326c6bbfd58c22244215e431948a" "metadata" "--no-deps" "--format-version=1", kill_on_drop: false }`
[INFO] [stdout] f761dfbb1ebcc476a88ea062bab0934762513888a9a819babdaa12770096f823
[INFO] running `Command { std: "docker" "start" "-a" "f761dfbb1ebcc476a88ea062bab0934762513888a9a819babdaa12770096f823", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "inspect" "f761dfbb1ebcc476a88ea062bab0934762513888a9a819babdaa12770096f823", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "f761dfbb1ebcc476a88ea062bab0934762513888a9a819babdaa12770096f823", kill_on_drop: false }`
[INFO] [stdout] f761dfbb1ebcc476a88ea062bab0934762513888a9a819babdaa12770096f823
[INFO] running `Command { std: "docker" "create" "-v" "/var/lib/crater-agent-workspace/builds/worker-7-tc1/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-7-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@sha256:2788e3201cd34a07e3172128adcd8b3090168a8e3bcc40d7c032b9dda1df7d1c" "/opt/rustwide/cargo-home/bin/cargo" "+385fa9d845dd326c6bbfd58c22244215e431948a" "check" "--frozen" "--all" "--all-targets" "--message-format=json", kill_on_drop: false }`
[INFO] [stdout] b4c359bd7f77132feebc7e45c5b148b2e4d2737164953c16d28e336a5685b7d0
[INFO] running `Command { std: "docker" "start" "-a" "b4c359bd7f77132feebc7e45c5b148b2e4d2737164953c16d28e336a5685b7d0", kill_on_drop: false }`
[INFO] [stderr]    Compiling libc v0.2.49
[INFO] [stderr]    Compiling num-traits v0.2.6
[INFO] [stderr]    Compiling num-integer v0.1.39
[INFO] [stderr]    Compiling regex v1.1.2
[INFO] [stderr]     Checking arc-swap v0.3.7
[INFO] [stderr]     Checking linked-hash-map v0.5.1
[INFO] [stderr]     Checking regex-syntax v0.6.5
[INFO] [stderr]     Checking aho-corasick v0.6.10
[INFO] [stderr]     Checking yaml-rust v0.4.3
[INFO] [stderr]     Checking time v0.1.42
[INFO] [stderr]     Checking signal-hook v0.1.8
[INFO] [stderr]     Checking chrono v0.4.6
[INFO] [stderr]     Checking tacron v0.1.0 (/opt/rustwide/workdir)
[INFO] [stdout] warning: trait objects without an explicit `dyn` are deprecated
[INFO] [stdout]   --> src/main.rs:66:40
[INFO] [stdout]    |
[INFO] [stdout] 66 | fn add_sighup_handler(readers: Vec<Box<Reader + Sync + Send>>, tacrons: Arc<RwLock<Vec<TaCron>>>) {
[INFO] [stdout]    |                                        ^^^^^^^^^^^^^^^^^^^^
[INFO] [stdout]    |
[INFO] [stdout]    = warning: this is accepted in the current edition (Rust 2018) 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]    = note: `#[warn(bare_trait_objects)]` on by default
[INFO] [stdout] help: if this is an object-safe trait, use `dyn`
[INFO] [stdout]    |
[INFO] [stdout] 66 | fn add_sighup_handler(readers: Vec<Box<dyn Reader + Sync + Send>>, tacrons: Arc<RwLock<Vec<TaCron>>>) {
[INFO] [stdout]    |                                        +++
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: trait objects without an explicit `dyn` are deprecated
[INFO] [stdout]   --> src/reader/mod.rs:30:14
[INFO] [stdout]    |
[INFO] [stdout] 30 | ) -> Vec<Box<Reader + Sync + Send>> {
[INFO] [stdout]    |              ^^^^^^^^^^^^^^^^^^^^
[INFO] [stdout]    |
[INFO] [stdout]    = warning: this is accepted in the current edition (Rust 2018) 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: if this is an object-safe trait, use `dyn`
[INFO] [stdout]    |
[INFO] [stdout] 30 | ) -> Vec<Box<dyn Reader + Sync + Send>> {
[INFO] [stdout]    |              +++
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: trait objects without an explicit `dyn` are deprecated
[INFO] [stdout]   --> src/reader/mod.rs:49:43
[INFO] [stdout]    |
[INFO] [stdout] 49 | pub fn retrieve_tacrons(readers: &Vec<Box<Reader + Sync + Send>>) -> Vec<TaCron> {
[INFO] [stdout]    |                                           ^^^^^^^^^^^^^^^^^^^^
[INFO] [stdout]    |
[INFO] [stdout]    = warning: this is accepted in the current edition (Rust 2018) 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: if this is an object-safe trait, use `dyn`
[INFO] [stdout]    |
[INFO] [stdout] 49 | pub fn retrieve_tacrons(readers: &Vec<Box<dyn Reader + Sync + Send>>) -> Vec<TaCron> {
[INFO] [stdout]    |                                           +++
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: trait objects without an explicit `dyn` are deprecated
[INFO] [stdout]   --> src/reader/crontab_reader.rs:48:27
[INFO] [stdout]    |
[INFO] [stdout] 48 |     readers: &mut Vec<Box<Reader + Sync + Send>>, users: &Vec<String>,
[INFO] [stdout]    |                           ^^^^^^^^^^^^^^^^^^^^
[INFO] [stdout]    |
[INFO] [stdout]    = warning: this is accepted in the current edition (Rust 2018) 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: if this is an object-safe trait, use `dyn`
[INFO] [stdout]    |
[INFO] [stdout] 48 |     readers: &mut Vec<Box<dyn Reader + Sync + Send>>, users: &Vec<String>,
[INFO] [stdout]    |                           +++
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: trait objects without an explicit `dyn` are deprecated
[INFO] [stdout]   --> src/reader/file_reader.rs:81:27
[INFO] [stdout]    |
[INFO] [stdout] 81 |     readers: &mut Vec<Box<Reader + Sync + Send>>, crontabs: &Vec<String>,
[INFO] [stdout]    |                           ^^^^^^^^^^^^^^^^^^^^
[INFO] [stdout]    |
[INFO] [stdout]    = warning: this is accepted in the current edition (Rust 2018) 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: if this is an object-safe trait, use `dyn`
[INFO] [stdout]    |
[INFO] [stdout] 81 |     readers: &mut Vec<Box<dyn Reader + Sync + Send>>, crontabs: &Vec<String>,
[INFO] [stdout]    |                           +++
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: trait objects without an explicit `dyn` are deprecated
[INFO] [stdout]   --> src/main.rs:66:40
[INFO] [stdout]    |
[INFO] [stdout] 66 | fn add_sighup_handler(readers: Vec<Box<Reader + Sync + Send>>, tacrons: Arc<RwLock<Vec<TaCron>>>) {
[INFO] [stdout]    |                                        ^^^^^^^^^^^^^^^^^^^^
[INFO] [stdout]    |
[INFO] [stdout]    = warning: this is accepted in the current edition (Rust 2018) 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]    = note: `#[warn(bare_trait_objects)]` on by default
[INFO] [stdout] help: if this is an object-safe trait, use `dyn`
[INFO] [stdout]    |
[INFO] [stdout] 66 | fn add_sighup_handler(readers: Vec<Box<dyn Reader + Sync + Send>>, tacrons: Arc<RwLock<Vec<TaCron>>>) {
[INFO] [stdout]    |                                        +++
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: trait objects without an explicit `dyn` are deprecated
[INFO] [stdout]   --> src/reader/mod.rs:31:30
[INFO] [stdout]    |
[INFO] [stdout] 31 |     let mut readers: Vec<Box<Reader + Sync + Send>> = Vec::new();
[INFO] [stdout]    |                              ^^^^^^^^^^^^^^^^^^^^
[INFO] [stdout]    |
[INFO] [stdout]    = warning: this is accepted in the current edition (Rust 2018) 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: if this is an object-safe trait, use `dyn`
[INFO] [stdout]    |
[INFO] [stdout] 31 |     let mut readers: Vec<Box<dyn Reader + Sync + Send>> = Vec::new();
[INFO] [stdout]    |                              +++
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: trait objects without an explicit `dyn` are deprecated
[INFO] [stdout]   --> src/reader/mod.rs:35:26
[INFO] [stdout]    |
[INFO] [stdout] 35 |         fn(&mut Vec<Box<(Reader + Send + Sync)>>, &Vec<String>),
[INFO] [stdout]    |                          ^^^^^^^^^^^^^^^^^^^^
[INFO] [stdout]    |
[INFO] [stdout]    = warning: this is accepted in the current edition (Rust 2018) 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: if this is an object-safe trait, use `dyn`
[INFO] [stdout]    |
[INFO] [stdout] 35 |         fn(&mut Vec<Box<(dyn Reader + Send + Sync)>>, &Vec<String>),
[INFO] [stdout]    |                          +++
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: trait objects without an explicit `dyn` are deprecated
[INFO] [stdout]   --> src/main.rs:51:26
[INFO] [stdout]    |
[INFO] [stdout] 51 |     let readers: Vec<Box<Reader + Sync + Send>>;
[INFO] [stdout]    |                          ^^^^^^^^^^^^^^^^^^^^
[INFO] [stdout]    |
[INFO] [stdout]    = warning: this is accepted in the current edition (Rust 2018) 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: if this is an object-safe trait, use `dyn`
[INFO] [stdout]    |
[INFO] [stdout] 51 |     let readers: Vec<Box<dyn Reader + Sync + Send>>;
[INFO] [stdout]    |                          +++
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: trait objects without an explicit `dyn` are deprecated
[INFO] [stdout]   --> src/reader/mod.rs:30:14
[INFO] [stdout]    |
[INFO] [stdout] 30 | ) -> Vec<Box<Reader + Sync + Send>> {
[INFO] [stdout]    |              ^^^^^^^^^^^^^^^^^^^^
[INFO] [stdout]    |
[INFO] [stdout]    = warning: this is accepted in the current edition (Rust 2018) 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: if this is an object-safe trait, use `dyn`
[INFO] [stdout]    |
[INFO] [stdout] 30 | ) -> Vec<Box<dyn Reader + Sync + Send>> {
[INFO] [stdout]    |              +++
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: trait objects without an explicit `dyn` are deprecated
[INFO] [stdout]   --> src/reader/mod.rs:49:43
[INFO] [stdout]    |
[INFO] [stdout] 49 | pub fn retrieve_tacrons(readers: &Vec<Box<Reader + Sync + Send>>) -> Vec<TaCron> {
[INFO] [stdout]    |                                           ^^^^^^^^^^^^^^^^^^^^
[INFO] [stdout]    |
[INFO] [stdout]    = warning: this is accepted in the current edition (Rust 2018) 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: if this is an object-safe trait, use `dyn`
[INFO] [stdout]    |
[INFO] [stdout] 49 | pub fn retrieve_tacrons(readers: &Vec<Box<dyn Reader + Sync + Send>>) -> Vec<TaCron> {
[INFO] [stdout]    |                                           +++
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: trait objects without an explicit `dyn` are deprecated
[INFO] [stdout]   --> src/reader/crontab_reader.rs:48:27
[INFO] [stdout]    |
[INFO] [stdout] 48 |     readers: &mut Vec<Box<Reader + Sync + Send>>, users: &Vec<String>,
[INFO] [stdout]    |                           ^^^^^^^^^^^^^^^^^^^^
[INFO] [stdout]    |
[INFO] [stdout]    = warning: this is accepted in the current edition (Rust 2018) 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: if this is an object-safe trait, use `dyn`
[INFO] [stdout]    |
[INFO] [stdout] 48 |     readers: &mut Vec<Box<dyn Reader + Sync + Send>>, users: &Vec<String>,
[INFO] [stdout]    |                           +++
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: trait objects without an explicit `dyn` are deprecated
[INFO] [stdout]   --> src/reader/file_reader.rs:81:27
[INFO] [stdout]    |
[INFO] [stdout] 81 |     readers: &mut Vec<Box<Reader + Sync + Send>>, crontabs: &Vec<String>,
[INFO] [stdout]    |                           ^^^^^^^^^^^^^^^^^^^^
[INFO] [stdout]    |
[INFO] [stdout]    = warning: this is accepted in the current edition (Rust 2018) 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: if this is an object-safe trait, use `dyn`
[INFO] [stdout]    |
[INFO] [stdout] 81 |     readers: &mut Vec<Box<dyn Reader + Sync + Send>>, crontabs: &Vec<String>,
[INFO] [stdout]    |                           +++
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: trait objects without an explicit `dyn` are deprecated
[INFO] [stdout]    --> src/reader/file_reader.rs:125:34
[INFO] [stdout]     |
[INFO] [stdout] 125 |         let mut readers: Vec<Box<Reader + Sync + Send>> = Vec::new();
[INFO] [stdout]     |                                  ^^^^^^^^^^^^^^^^^^^^
[INFO] [stdout]     |
[INFO] [stdout]     = warning: this is accepted in the current edition (Rust 2018) 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: if this is an object-safe trait, use `dyn`
[INFO] [stdout]     |
[INFO] [stdout] 125 |         let mut readers: Vec<Box<dyn Reader + Sync + Send>> = Vec::new();
[INFO] [stdout]     |                                  +++
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: trait objects without an explicit `dyn` are deprecated
[INFO] [stdout]   --> src/reader/mod.rs:31:30
[INFO] [stdout]    |
[INFO] [stdout] 31 |     let mut readers: Vec<Box<Reader + Sync + Send>> = Vec::new();
[INFO] [stdout]    |                              ^^^^^^^^^^^^^^^^^^^^
[INFO] [stdout]    |
[INFO] [stdout]    = warning: this is accepted in the current edition (Rust 2018) 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: if this is an object-safe trait, use `dyn`
[INFO] [stdout]    |
[INFO] [stdout] 31 |     let mut readers: Vec<Box<dyn Reader + Sync + Send>> = Vec::new();
[INFO] [stdout]    |                              +++
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: trait objects without an explicit `dyn` are deprecated
[INFO] [stdout]   --> src/reader/mod.rs:35:26
[INFO] [stdout]    |
[INFO] [stdout] 35 |         fn(&mut Vec<Box<(Reader + Send + Sync)>>, &Vec<String>),
[INFO] [stdout]    |                          ^^^^^^^^^^^^^^^^^^^^
[INFO] [stdout]    |
[INFO] [stdout]    = warning: this is accepted in the current edition (Rust 2018) 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: if this is an object-safe trait, use `dyn`
[INFO] [stdout]    |
[INFO] [stdout] 35 |         fn(&mut Vec<Box<(dyn Reader + Send + Sync)>>, &Vec<String>),
[INFO] [stdout]    |                          +++
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: 8 warnings emitted
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: trait objects without an explicit `dyn` are deprecated
[INFO] [stdout]   --> src/main.rs:51:26
[INFO] [stdout]    |
[INFO] [stdout] 51 |     let readers: Vec<Box<Reader + Sync + Send>>;
[INFO] [stdout]    |                          ^^^^^^^^^^^^^^^^^^^^
[INFO] [stdout]    |
[INFO] [stdout]    = warning: this is accepted in the current edition (Rust 2018) 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: if this is an object-safe trait, use `dyn`
[INFO] [stdout]    |
[INFO] [stdout] 51 |     let readers: Vec<Box<dyn Reader + Sync + Send>>;
[INFO] [stdout]    |                          +++
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused return value of `Result::<T, E>::is_err` that must be used
[INFO] [stdout]   --> src/time_units/days_of_week.rs:63:9
[INFO] [stdout]    |
[INFO] [stdout] 63 |         DaysOfWeek::value_from_name("foo").is_err();
[INFO] [stdout]    |         ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
[INFO] [stdout]    |
[INFO] [stdout]    = note: if you intended to assert that this is err, consider `.unwrap_err()` instead
[INFO] [stdout]    = note: `#[warn(unused_must_use)]` on by default
[INFO] [stdout] help: use `let _ = ...` to ignore the resulting value
[INFO] [stdout]    |
[INFO] [stdout] 63 |         let _ = DaysOfWeek::value_from_name("foo").is_err();
[INFO] [stdout]    |         +++++++
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused return value of `Result::<T, E>::is_err` that must be used
[INFO] [stdout]   --> src/time_units/months.rs:73:9
[INFO] [stdout]    |
[INFO] [stdout] 73 |         Months::value_from_name("foo").is_err();
[INFO] [stdout]    |         ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
[INFO] [stdout]    |
[INFO] [stdout]    = note: if you intended to assert that this is err, consider `.unwrap_err()` instead
[INFO] [stdout] help: use `let _ = ...` to ignore the resulting value
[INFO] [stdout]    |
[INFO] [stdout] 73 |         let _ = Months::value_from_name("foo").is_err();
[INFO] [stdout]    |         +++++++
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: 11 warnings emitted
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stderr]     Finished `dev` profile [unoptimized + debuginfo] target(s) in 4.32s
[INFO] running `Command { std: "docker" "inspect" "b4c359bd7f77132feebc7e45c5b148b2e4d2737164953c16d28e336a5685b7d0", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "b4c359bd7f77132feebc7e45c5b148b2e4d2737164953c16d28e336a5685b7d0", kill_on_drop: false }`
[INFO] [stdout] b4c359bd7f77132feebc7e45c5b148b2e4d2737164953c16d28e336a5685b7d0