[INFO] cloning repository https://github.com/fin-ger/declarative-state-machine
[INFO] running `Command { std: "git" "-c" "credential.helper=" "-c" "credential.helper=/workspace/cargo-home/bin/git-credential-null" "clone" "--bare" "https://github.com/fin-ger/declarative-state-machine" "/workspace/cache/git-repos/https%3A%2F%2Fgithub.com%2Ffin-ger%2Fdeclarative-state-machine", kill_on_drop: false }`
[INFO] [stderr] Cloning into bare repository '/workspace/cache/git-repos/https%3A%2F%2Fgithub.com%2Ffin-ger%2Fdeclarative-state-machine'...
[INFO] running `Command { std: "git" "rev-parse" "HEAD", kill_on_drop: false }`
[INFO] [stdout] 301f8d92408bed8eb92b99caf23175da73673c6a
[INFO] checking fin-ger/declarative-state-machine against try#012cd62c9add58ab3910e44c137d87db3ab70f61 for pr-155915
[INFO] running `Command { std: "git" "clone" "/workspace/cache/git-repos/https%3A%2F%2Fgithub.com%2Ffin-ger%2Fdeclarative-state-machine" "/workspace/builds/worker-6-tc2/source", kill_on_drop: false }`
[INFO] [stderr] Cloning into '/workspace/builds/worker-6-tc2/source'...
[INFO] [stderr] done.
[INFO] started tweaking git repo https://github.com/fin-ger/declarative-state-machine
[INFO] finished tweaking git repo https://github.com/fin-ger/declarative-state-machine
[INFO] tweaked toml for git repo https://github.com/fin-ger/declarative-state-machine written to /workspace/builds/worker-6-tc2/source/Cargo.toml
[INFO] validating manifest of git repo https://github.com/fin-ger/declarative-state-machine on toolchain 012cd62c9add58ab3910e44c137d87db3ab70f61
[INFO] running `Command { std: CARGO_HOME="/workspace/cargo-home" RUSTUP_HOME="/workspace/rustup-home" "/workspace/cargo-home/bin/cargo" "+012cd62c9add58ab3910e44c137d87db3ab70f61" "metadata" "--manifest-path" "Cargo.toml" "--no-deps", kill_on_drop: false }`
[INFO] crate git repo https://github.com/fin-ger/declarative-state-machine 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" "+012cd62c9add58ab3910e44c137d87db3ab70f61" "fetch" "--manifest-path" "Cargo.toml", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "create" "-v" "/var/lib/crater-agent-workspace/builds/worker-6-tc2/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-6-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" "+012cd62c9add58ab3910e44c137d87db3ab70f61" "metadata" "--no-deps" "--format-version=1", kill_on_drop: false }`
[INFO] [stdout] 7e8a97303ff628bf8b8b3ba7771977b7f23ef6ec40ae21029e7d3704466a1b1b
[INFO] running `Command { std: "docker" "start" "-a" "7e8a97303ff628bf8b8b3ba7771977b7f23ef6ec40ae21029e7d3704466a1b1b", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "inspect" "7e8a97303ff628bf8b8b3ba7771977b7f23ef6ec40ae21029e7d3704466a1b1b", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "7e8a97303ff628bf8b8b3ba7771977b7f23ef6ec40ae21029e7d3704466a1b1b", kill_on_drop: false }`
[INFO] [stdout] 7e8a97303ff628bf8b8b3ba7771977b7f23ef6ec40ae21029e7d3704466a1b1b
[INFO] running `Command { std: "docker" "create" "-v" "/var/lib/crater-agent-workspace/builds/worker-6-tc2/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-6-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=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" "+012cd62c9add58ab3910e44c137d87db3ab70f61" "check" "--frozen" "--all" "--all-targets" "--message-format=json", kill_on_drop: false }`
[INFO] [stdout] 91e64c12d8f7be4ba19bee6ca506f2068adf52798e9efe9ea08b956ce52b5517
[INFO] running `Command { std: "docker" "start" "-a" "91e64c12d8f7be4ba19bee6ca506f2068adf52798e9efe9ea08b956ce52b5517", kill_on_drop: false }`
[INFO] [stderr]    Compiling proc-macro2 v0.4.27
[INFO] [stderr]     Checking unicode-xid v0.1.0
[INFO] [stderr]     Checking quick-error v1.2.2
[INFO] [stderr]     Checking quote v0.6.11
[INFO] [stderr]     Checking syn v0.15.27
[INFO] [stderr]     Checking declarative-state-machine v0.1.0 (/opt/rustwide/workdir)
[INFO] [stdout] warning: trait objects without an explicit `dyn` are deprecated
[INFO] [stdout]  --> src/events.rs:5:16
[INFO] [stdout]   |
[INFO] [stdout] 5 |     iter: &mut Iterator<Item = TokenTree>,
[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/edition-guide/rust-2021/warnings-promoted-to-error.html>
[INFO] [stdout]   = note: `#[warn(bare_trait_objects)]` (part of `#[warn(rust_2021_compatibility)]`) on by default
[INFO] [stdout] help: if this is a dyn-compatible trait, use `dyn`
[INFO] [stdout]   |
[INFO] [stdout] 5 |     iter: &mut dyn Iterator<Item = TokenTree>,
[INFO] [stdout]   |                +++
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: trait objects without an explicit `dyn` are deprecated
[INFO] [stdout]   --> src/events.rs:89:31
[INFO] [stdout]    |
[INFO] [stdout] 89 | pub fn parse_event(iter: &mut Iterator<Item = TokenTree>, span: Span) -> StateMachineResult<Event> {
[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/edition-guide/rust-2021/warnings-promoted-to-error.html>
[INFO] [stdout] help: if this is a dyn-compatible trait, use `dyn`
[INFO] [stdout]    |
[INFO] [stdout] 89 | pub fn parse_event(iter: &mut dyn Iterator<Item = TokenTree>, span: Span) -> StateMachineResult<Event> {
[INFO] [stdout]    |                               +++
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: trait objects without an explicit `dyn` are deprecated
[INFO] [stdout]   --> src/states.rs:30:16
[INFO] [stdout]    |
[INFO] [stdout] 30 |     iter: &mut Iterator<Item = TokenTree>,
[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/edition-guide/rust-2021/warnings-promoted-to-error.html>
[INFO] [stdout] help: if this is a dyn-compatible trait, use `dyn`
[INFO] [stdout]    |
[INFO] [stdout] 30 |     iter: &mut dyn Iterator<Item = TokenTree>,
[INFO] [stdout]    |                +++
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: trait objects without an explicit `dyn` are deprecated
[INFO] [stdout]   --> src/states.rs:77:16
[INFO] [stdout]    |
[INFO] [stdout] 77 |     iter: &mut Iterator<Item = TokenTree>,
[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/edition-guide/rust-2021/warnings-promoted-to-error.html>
[INFO] [stdout] help: if this is a dyn-compatible trait, use `dyn`
[INFO] [stdout]    |
[INFO] [stdout] 77 |     iter: &mut dyn Iterator<Item = TokenTree>,
[INFO] [stdout]    |                +++
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: trait objects without an explicit `dyn` are deprecated
[INFO] [stdout]  --> src/events.rs:5:16
[INFO] [stdout]   |
[INFO] [stdout] 5 |     iter: &mut Iterator<Item = TokenTree>,
[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/edition-guide/rust-2021/warnings-promoted-to-error.html>
[INFO] [stdout]   = note: `#[warn(bare_trait_objects)]` (part of `#[warn(rust_2021_compatibility)]`) on by default
[INFO] [stdout] help: if this is a dyn-compatible trait, use `dyn`
[INFO] [stdout]   |
[INFO] [stdout] 5 |     iter: &mut dyn Iterator<Item = TokenTree>,
[INFO] [stdout]   |                +++
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: trait objects without an explicit `dyn` are deprecated
[INFO] [stdout]   --> src/events.rs:89:31
[INFO] [stdout]    |
[INFO] [stdout] 89 | pub fn parse_event(iter: &mut Iterator<Item = TokenTree>, span: Span) -> StateMachineResult<Event> {
[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/edition-guide/rust-2021/warnings-promoted-to-error.html>
[INFO] [stdout] help: if this is a dyn-compatible trait, use `dyn`
[INFO] [stdout]    |
[INFO] [stdout] 89 | pub fn parse_event(iter: &mut dyn Iterator<Item = TokenTree>, span: Span) -> StateMachineResult<Event> {
[INFO] [stdout]    |                               +++
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: trait objects without an explicit `dyn` are deprecated
[INFO] [stdout]   --> src/transitions.rs:13:16
[INFO] [stdout]    |
[INFO] [stdout] 13 |     iter: &mut Iterator<Item = TokenTree>,
[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/edition-guide/rust-2021/warnings-promoted-to-error.html>
[INFO] [stdout] help: if this is a dyn-compatible trait, use `dyn`
[INFO] [stdout]    |
[INFO] [stdout] 13 |     iter: &mut dyn Iterator<Item = TokenTree>,
[INFO] [stdout]    |                +++
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: trait objects without an explicit `dyn` are deprecated
[INFO] [stdout]    --> src/transitions.rs:106:16
[INFO] [stdout]     |
[INFO] [stdout] 106 |     iter: &mut Iterator<Item = TokenTree>,
[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/edition-guide/rust-2021/warnings-promoted-to-error.html>
[INFO] [stdout] help: if this is a dyn-compatible trait, use `dyn`
[INFO] [stdout]     |
[INFO] [stdout] 106 |     iter: &mut dyn Iterator<Item = TokenTree>,
[INFO] [stdout]     |                +++
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: trait objects without an explicit `dyn` are deprecated
[INFO] [stdout]   --> src/states.rs:30:16
[INFO] [stdout]    |
[INFO] [stdout] 30 |     iter: &mut Iterator<Item = TokenTree>,
[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/edition-guide/rust-2021/warnings-promoted-to-error.html>
[INFO] [stdout] help: if this is a dyn-compatible trait, use `dyn`
[INFO] [stdout]    |
[INFO] [stdout] 30 |     iter: &mut dyn Iterator<Item = TokenTree>,
[INFO] [stdout]    |                +++
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: trait objects without an explicit `dyn` are deprecated
[INFO] [stdout]   --> src/states.rs:77:16
[INFO] [stdout]    |
[INFO] [stdout] 77 |     iter: &mut Iterator<Item = TokenTree>,
[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/edition-guide/rust-2021/warnings-promoted-to-error.html>
[INFO] [stdout] help: if this is a dyn-compatible trait, use `dyn`
[INFO] [stdout]    |
[INFO] [stdout] 77 |     iter: &mut dyn Iterator<Item = TokenTree>,
[INFO] [stdout]    |                +++
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: trait objects without an explicit `dyn` are deprecated
[INFO] [stdout]   --> src/transitions.rs:13:16
[INFO] [stdout]    |
[INFO] [stdout] 13 |     iter: &mut Iterator<Item = TokenTree>,
[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/edition-guide/rust-2021/warnings-promoted-to-error.html>
[INFO] [stdout] help: if this is a dyn-compatible trait, use `dyn`
[INFO] [stdout]    |
[INFO] [stdout] 13 |     iter: &mut dyn Iterator<Item = TokenTree>,
[INFO] [stdout]    |                +++
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: trait objects without an explicit `dyn` are deprecated
[INFO] [stdout]    --> src/transitions.rs:106:16
[INFO] [stdout]     |
[INFO] [stdout] 106 |     iter: &mut Iterator<Item = TokenTree>,
[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/edition-guide/rust-2021/warnings-promoted-to-error.html>
[INFO] [stdout] help: if this is a dyn-compatible trait, use `dyn`
[INFO] [stdout]     |
[INFO] [stdout] 106 |     iter: &mut dyn Iterator<Item = TokenTree>,
[INFO] [stdout]     |                +++
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: variable does not need to be mutable
[INFO] [stdout]   --> src/states.rs:82:9
[INFO] [stdout]    |
[INFO] [stdout] 82 |     let mut definition;
[INFO] [stdout]    |         ----^^^^^^^^^^
[INFO] [stdout]    |         |
[INFO] [stdout]    |         help: remove this `mut`
[INFO] [stdout]    |
[INFO] [stdout]    = note: `#[warn(unused_mut)]` (part of `#[warn(unused)]`) on by default
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: variable does not need to be mutable
[INFO] [stdout]   --> src/states.rs:82:9
[INFO] [stdout]    |
[INFO] [stdout] 82 |     let mut definition;
[INFO] [stdout]    |         ----^^^^^^^^^^
[INFO] [stdout]    |         |
[INFO] [stdout]    |         help: remove this `mut`
[INFO] [stdout]    |
[INFO] [stdout]    = note: `#[warn(unused_mut)]` (part of `#[warn(unused)]`) on by default
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: trait objects without an explicit `dyn` are deprecated
[INFO] [stdout]  --> src/events.rs:5:16
[INFO] [stdout]   |
[INFO] [stdout] 5 |     iter: &mut Iterator<Item = TokenTree>,
[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/edition-guide/rust-2021/warnings-promoted-to-error.html>
[INFO] [stdout]   = note: `#[warn(bare_trait_objects)]` (part of `#[warn(rust_2021_compatibility)]`) on by default
[INFO] [stdout] help: if this is a dyn-compatible trait, use `dyn`
[INFO] [stdout]   |
[INFO] [stdout] 5 |     iter: &mut dyn Iterator<Item = TokenTree>,
[INFO] [stdout]   |                +++
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: trait objects without an explicit `dyn` are deprecated
[INFO] [stdout]   --> src/events.rs:89:31
[INFO] [stdout]    |
[INFO] [stdout] 89 | pub fn parse_event(iter: &mut Iterator<Item = TokenTree>, span: Span) -> StateMachineResult<Event> {
[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/edition-guide/rust-2021/warnings-promoted-to-error.html>
[INFO] [stdout] help: if this is a dyn-compatible trait, use `dyn`
[INFO] [stdout]    |
[INFO] [stdout] 89 | pub fn parse_event(iter: &mut dyn Iterator<Item = TokenTree>, span: Span) -> StateMachineResult<Event> {
[INFO] [stdout]    |                               +++
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: trait objects without an explicit `dyn` are deprecated
[INFO] [stdout]   --> src/states.rs:30:16
[INFO] [stdout]    |
[INFO] [stdout] 30 |     iter: &mut Iterator<Item = TokenTree>,
[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/edition-guide/rust-2021/warnings-promoted-to-error.html>
[INFO] [stdout] help: if this is a dyn-compatible trait, use `dyn`
[INFO] [stdout]    |
[INFO] [stdout] 30 |     iter: &mut dyn Iterator<Item = TokenTree>,
[INFO] [stdout]    |                +++
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: trait objects without an explicit `dyn` are deprecated
[INFO] [stdout]   --> src/states.rs:77:16
[INFO] [stdout]    |
[INFO] [stdout] 77 |     iter: &mut Iterator<Item = TokenTree>,
[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/edition-guide/rust-2021/warnings-promoted-to-error.html>
[INFO] [stdout] help: if this is a dyn-compatible trait, use `dyn`
[INFO] [stdout]    |
[INFO] [stdout] 77 |     iter: &mut dyn Iterator<Item = TokenTree>,
[INFO] [stdout]    |                +++
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: trait objects without an explicit `dyn` are deprecated
[INFO] [stdout]   --> src/transitions.rs:13:16
[INFO] [stdout]    |
[INFO] [stdout] 13 |     iter: &mut Iterator<Item = TokenTree>,
[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/edition-guide/rust-2021/warnings-promoted-to-error.html>
[INFO] [stdout] help: if this is a dyn-compatible trait, use `dyn`
[INFO] [stdout]    |
[INFO] [stdout] 13 |     iter: &mut dyn Iterator<Item = TokenTree>,
[INFO] [stdout]    |                +++
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: trait objects without an explicit `dyn` are deprecated
[INFO] [stdout]    --> src/transitions.rs:106:16
[INFO] [stdout]     |
[INFO] [stdout] 106 |     iter: &mut Iterator<Item = TokenTree>,
[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/edition-guide/rust-2021/warnings-promoted-to-error.html>
[INFO] [stdout] help: if this is a dyn-compatible trait, use `dyn`
[INFO] [stdout]     |
[INFO] [stdout] 106 |     iter: &mut dyn Iterator<Item = TokenTree>,
[INFO] [stdout]     |                +++
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: variable does not need to be mutable
[INFO] [stdout]   --> src/states.rs:82:9
[INFO] [stdout]    |
[INFO] [stdout] 82 |     let mut definition;
[INFO] [stdout]    |         ----^^^^^^^^^^
[INFO] [stdout]    |         |
[INFO] [stdout]    |         help: remove this `mut`
[INFO] [stdout]    |
[INFO] [stdout]    = note: `#[warn(unused_mut)]` (part of `#[warn(unused)]`) on by default
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stderr]     Finished `dev` profile [unoptimized + debuginfo] target(s) in 4.22s
[INFO] running `Command { std: "docker" "inspect" "91e64c12d8f7be4ba19bee6ca506f2068adf52798e9efe9ea08b956ce52b5517", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "91e64c12d8f7be4ba19bee6ca506f2068adf52798e9efe9ea08b956ce52b5517", kill_on_drop: false }`
[INFO] [stdout] 91e64c12d8f7be4ba19bee6ca506f2068adf52798e9efe9ea08b956ce52b5517
