[INFO] fetching crate stringtree 0.2.0...
[INFO] testing stringtree-0.2.0 against beta-2026-04-21 for beta-1.96-2
[INFO] extracting crate stringtree 0.2.0 into /workspace/builds/worker-6-tc2/source
[INFO] started tweaking crates.io crate stringtree 0.2.0
[INFO] finished tweaking crates.io crate stringtree 0.2.0
[INFO] tweaked toml for crates.io crate stringtree 0.2.0 written to /workspace/builds/worker-6-tc2/source/Cargo.toml
[INFO] validating manifest of crates.io crate stringtree 0.2.0 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] running `Command { std: CARGO_HOME="/workspace/cargo-home" RUSTUP_HOME="/workspace/rustup-home" "/workspace/cargo-home/bin/cargo" "+beta-2026-04-21" "generate-lockfile" "--manifest-path" "Cargo.toml", kill_on_drop: false }`
[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: `package.edition` is unspecified, defaulting to `2015` while the latest is `2024`
[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" "+beta-2026-04-21" "metadata" "--no-deps" "--format-version=1", kill_on_drop: false }`
[INFO] [stdout] 6823d56e5bfcb69c5661c26e444ab8da54b296849889a1f5d90f4bde65879eaf
[INFO] running `Command { std: "docker" "start" "-a" "6823d56e5bfcb69c5661c26e444ab8da54b296849889a1f5d90f4bde65879eaf", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "inspect" "6823d56e5bfcb69c5661c26e444ab8da54b296849889a1f5d90f4bde65879eaf", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "6823d56e5bfcb69c5661c26e444ab8da54b296849889a1f5d90f4bde65879eaf", kill_on_drop: false }`
[INFO] [stdout] 6823d56e5bfcb69c5661c26e444ab8da54b296849889a1f5d90f4bde65879eaf
[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=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] 496d58d278905a6007ab9c6fb3c6bfaa48700b86ff922a8870d6338f5719b395
[INFO] running `Command { std: "docker" "start" "-a" "496d58d278905a6007ab9c6fb3c6bfaa48700b86ff922a8870d6338f5719b395", kill_on_drop: false }`
[INFO] [stderr] warning: `package.edition` is unspecified, defaulting to `2015` while the latest is `2024`
[INFO] [stderr]    Compiling stringtree v0.2.0 (/opt/rustwide/workdir)
[INFO] [stdout] warning: trait objects without an explicit `dyn` are deprecated
[INFO] [stdout]   --> src/lib.rs:73:44
[INFO] [stdout]    |
[INFO] [stdout] 73 | pub type StringTreeOption<'a> = Option<&'a StringTree>;
[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/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] 73 | pub type StringTreeOption<'a> = Option<&'a dyn StringTree>;
[INFO] [stdout]    |                                            +++
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: trait objects without an explicit `dyn` are deprecated
[INFO] [stdout]   --> src/lib.rs:84:29
[INFO] [stdout]    |
[INFO] [stdout] 84 | pub type StringTreeFn = Box<Fn() -> &'static str>;
[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/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] 84 | pub type StringTreeFn = Box<dyn Fn() -> &'static str>;
[INFO] [stdout]    |                             +++
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: trait objects without an explicit `dyn` are deprecated
[INFO] [stdout]   --> src/lib.rs:13:6
[INFO] [stdout]    |
[INFO] [stdout] 13 | impl StringTree {
[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/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 | impl dyn StringTree {
[INFO] [stdout]    |      +++
[INFO] [stdout] help: you might have intended to implement this trait for a given type
[INFO] [stdout]    |
[INFO] [stdout] 13 | impl StringTree for /* Type */ {
[INFO] [stdout]    |                 ++++++++++++++
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: trait objects without an explicit `dyn` are deprecated
[INFO] [stdout]   --> src/lib.rs:14:22
[INFO] [stdout]    |
[INFO] [stdout] 14 |     pub fn new(s: &[&StringTree]) -> StringTreeBuf {
[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/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] 14 |     pub fn new(s: &[&dyn StringTree]) -> StringTreeBuf {
[INFO] [stdout]    |                      +++
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stderr]     Finished `dev` profile [unoptimized + debuginfo] target(s) in 0.17s
[INFO] running `Command { std: "docker" "inspect" "496d58d278905a6007ab9c6fb3c6bfaa48700b86ff922a8870d6338f5719b395", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "496d58d278905a6007ab9c6fb3c6bfaa48700b86ff922a8870d6338f5719b395", kill_on_drop: false }`
[INFO] [stdout] 496d58d278905a6007ab9c6fb3c6bfaa48700b86ff922a8870d6338f5719b395
[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=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" "test" "--frozen" "--no-run" "--message-format=json", kill_on_drop: false }`
[INFO] [stdout] ec6251ed6127b2cd82cec00a21d3a47dea71fedab318b27e9545377ca4cdb96e
[INFO] running `Command { std: "docker" "start" "-a" "ec6251ed6127b2cd82cec00a21d3a47dea71fedab318b27e9545377ca4cdb96e", kill_on_drop: false }`
[INFO] [stderr] warning: `package.edition` is unspecified, defaulting to `2015` while the latest is `2024`
[INFO] [stdout] warning: trait objects without an explicit `dyn` are deprecated
[INFO] [stdout]   --> src/lib.rs:73:44
[INFO] [stdout]    |
[INFO] [stdout] 73 | pub type StringTreeOption<'a> = Option<&'a StringTree>;
[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/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] 73 | pub type StringTreeOption<'a> = Option<&'a dyn StringTree>;
[INFO] [stdout]    |                                            +++
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: trait objects without an explicit `dyn` are deprecated
[INFO] [stdout]   --> src/lib.rs:84:29
[INFO] [stdout]    |
[INFO] [stdout] 84 | pub type StringTreeFn = Box<Fn() -> &'static str>;
[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/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] 84 | pub type StringTreeFn = Box<dyn Fn() -> &'static str>;
[INFO] [stdout]    |                             +++
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: trait objects without an explicit `dyn` are deprecated
[INFO] [stdout]   --> src/lib.rs:13:6
[INFO] [stdout]    |
[INFO] [stdout] 13 | impl StringTree {
[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/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 | impl dyn StringTree {
[INFO] [stdout]    |      +++
[INFO] [stdout] help: you might have intended to implement this trait for a given type
[INFO] [stdout]    |
[INFO] [stdout] 13 | impl StringTree for /* Type */ {
[INFO] [stdout]    |                 ++++++++++++++
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: trait objects without an explicit `dyn` are deprecated
[INFO] [stdout]   --> src/lib.rs:14:22
[INFO] [stdout]    |
[INFO] [stdout] 14 |     pub fn new(s: &[&StringTree]) -> StringTreeBuf {
[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/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] 14 |     pub fn new(s: &[&dyn StringTree]) -> StringTreeBuf {
[INFO] [stdout]    |                      +++
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stderr]    Compiling stringtree v0.2.0 (/opt/rustwide/workdir)
[INFO] [stdout] warning: trait objects without an explicit `dyn` are deprecated
[INFO] [stdout]   --> src/lib.rs:73:44
[INFO] [stdout]    |
[INFO] [stdout] 73 | pub type StringTreeOption<'a> = Option<&'a StringTree>;
[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/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] 73 | pub type StringTreeOption<'a> = Option<&'a dyn StringTree>;
[INFO] [stdout]    |                                            +++
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: trait objects without an explicit `dyn` are deprecated
[INFO] [stdout]   --> src/lib.rs:84:29
[INFO] [stdout]    |
[INFO] [stdout] 84 | pub type StringTreeFn = Box<Fn() -> &'static str>;
[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/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] 84 | pub type StringTreeFn = Box<dyn Fn() -> &'static str>;
[INFO] [stdout]    |                             +++
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: trait objects without an explicit `dyn` are deprecated
[INFO] [stdout]   --> src/lib.rs:13:6
[INFO] [stdout]    |
[INFO] [stdout] 13 | impl StringTree {
[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/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 | impl dyn StringTree {
[INFO] [stdout]    |      +++
[INFO] [stdout] help: you might have intended to implement this trait for a given type
[INFO] [stdout]    |
[INFO] [stdout] 13 | impl StringTree for /* Type */ {
[INFO] [stdout]    |                 ++++++++++++++
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: trait objects without an explicit `dyn` are deprecated
[INFO] [stdout]   --> src/lib.rs:14:22
[INFO] [stdout]    |
[INFO] [stdout] 14 |     pub fn new(s: &[&StringTree]) -> StringTreeBuf {
[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/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] 14 |     pub fn new(s: &[&dyn StringTree]) -> StringTreeBuf {
[INFO] [stdout]    |                      +++
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: trait objects without an explicit `dyn` are deprecated
[INFO] [stdout]   --> src/lib.rs:99:18
[INFO] [stdout]    |
[INFO] [stdout] 99 |         let i0 = StringTree::indent(&"x");
[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/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] 99 |         let i0 = <dyn StringTree>::indent(&"x");
[INFO] [stdout]    |                  ++++           +
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: trait objects without an explicit `dyn` are deprecated
[INFO] [stdout]    --> src/lib.rs:112:20
[INFO] [stdout]     |
[INFO] [stdout] 112 |         assert_eq!(StringTree::new(&[]).to_string(), "");
[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/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] 112 |         assert_eq!(<dyn StringTree>::new(&[]).to_string(), "");
[INFO] [stdout]     |                    ++++           +
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: trait objects without an explicit `dyn` are deprecated
[INFO] [stdout]    --> src/lib.rs:113:20
[INFO] [stdout]     |
[INFO] [stdout] 113 |         assert_eq!(StringTree::new(&[&"foo"]).to_string(), "foo");
[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/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] 113 |         assert_eq!(<dyn StringTree>::new(&[&"foo"]).to_string(), "foo");
[INFO] [stdout]     |                    ++++           +
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: trait objects without an explicit `dyn` are deprecated
[INFO] [stdout]    --> src/lib.rs:114:20
[INFO] [stdout]     |
[INFO] [stdout] 114 |         assert_eq!(StringTree::new(&[&"foo", &"bar"]).to_string(), "foobar");
[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/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] 114 |         assert_eq!(<dyn StringTree>::new(&[&"foo", &"bar"]).to_string(), "foobar");
[INFO] [stdout]     |                    ++++           +
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: trait objects without an explicit `dyn` are deprecated
[INFO] [stdout]    --> src/lib.rs:116:18
[INFO] [stdout]     |
[INFO] [stdout] 116 |         let i2 = StringTree::indent("x").next().next();
[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/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] 116 |         let i2 = <dyn StringTree>::indent("x").next().next();
[INFO] [stdout]     |                  ++++           +
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: trait objects without an explicit `dyn` are deprecated
[INFO] [stdout]    --> src/lib.rs:117:20
[INFO] [stdout]     |
[INFO] [stdout] 117 |         assert_eq!(StringTree::new(&[&i2, &"bar"]).to_string(), "xxbar");
[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/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] 117 |         assert_eq!(<dyn StringTree>::new(&[&i2, &"bar"]).to_string(), "xxbar");
[INFO] [stdout]     |                    ++++           +
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: trait objects without an explicit `dyn` are deprecated
[INFO] [stdout]    --> src/lib.rs:120:20
[INFO] [stdout]     |
[INFO] [stdout] 120 |         assert_eq!(StringTree::new(&[&f]).to_string(), "foo");
[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/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] 120 |         assert_eq!(<dyn StringTree>::new(&[&f]).to_string(), "foo");
[INFO] [stdout]     |                    ++++           +
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: trait objects without an explicit `dyn` are deprecated
[INFO] [stdout]    --> src/lib.rs:121:20
[INFO] [stdout]     |
[INFO] [stdout] 121 |         assert_eq!(StringTree::new(&[&"bar", &f]).to_string(), "barfoo");
[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/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] 121 |         assert_eq!(<dyn StringTree>::new(&[&"bar", &f]).to_string(), "barfoo");
[INFO] [stdout]     |                    ++++           +
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: trait objects without an explicit `dyn` are deprecated
[INFO] [stdout]    --> src/lib.rs:124:17
[INFO] [stdout]     |
[INFO] [stdout] 124 |         let c: &StringTree = &StringTree::new(&[&"opt"]);
[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/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] 124 |         let c: &dyn StringTree = &StringTree::new(&[&"opt"]);
[INFO] [stdout]     |                 +++
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: trait objects without an explicit `dyn` are deprecated
[INFO] [stdout]    --> src/lib.rs:124:31
[INFO] [stdout]     |
[INFO] [stdout] 124 |         let c: &StringTree = &StringTree::new(&[&"opt"]);
[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/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] 124 |         let c: &StringTree = &<dyn StringTree>::new(&[&"opt"]);
[INFO] [stdout]     |                               ++++           +
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: trait objects without an explicit `dyn` are deprecated
[INFO] [stdout]    --> src/lib.rs:126:20
[INFO] [stdout]     |
[INFO] [stdout] 126 |         assert_eq!(StringTree::new(&[&none]).to_string(), "");
[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/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] 126 |         assert_eq!(<dyn StringTree>::new(&[&none]).to_string(), "");
[INFO] [stdout]     |                    ++++           +
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: trait objects without an explicit `dyn` are deprecated
[INFO] [stdout]    --> src/lib.rs:127:20
[INFO] [stdout]     |
[INFO] [stdout] 127 |         assert_eq!(StringTree::new(&[&some]).to_string(), "opt");
[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/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] 127 |         assert_eq!(<dyn StringTree>::new(&[&some]).to_string(), "opt");
[INFO] [stdout]     |                    ++++           +
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: trait objects without an explicit `dyn` are deprecated
[INFO] [stdout]    --> src/lib.rs:128:20
[INFO] [stdout]     |
[INFO] [stdout] 128 |         assert_eq!(StringTree::new(&[&"foo", &none, &some]).to_string(), "fooopt");
[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/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] 128 |         assert_eq!(<dyn StringTree>::new(&[&"foo", &none, &some]).to_string(), "fooopt");
[INFO] [stdout]     |                    ++++           +
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stderr]     Finished `test` profile [unoptimized + debuginfo] target(s) in 0.46s
[INFO] running `Command { std: "docker" "inspect" "ec6251ed6127b2cd82cec00a21d3a47dea71fedab318b27e9545377ca4cdb96e", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "ec6251ed6127b2cd82cec00a21d3a47dea71fedab318b27e9545377ca4cdb96e", kill_on_drop: false }`
[INFO] [stdout] ec6251ed6127b2cd82cec00a21d3a47dea71fedab318b27e9545377ca4cdb96e
[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=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" "test" "--frozen", kill_on_drop: false }`
[INFO] [stdout] 7c781bc473e85c8133e60fa98e9dd589819bf5fb9d5835c3473ebad5cd8c190d
[INFO] running `Command { std: "docker" "start" "-a" "7c781bc473e85c8133e60fa98e9dd589819bf5fb9d5835c3473ebad5cd8c190d", kill_on_drop: false }`
[INFO] [stderr] warning: `package.edition` is unspecified, defaulting to `2015` while the latest is `2024`
[INFO] [stderr] warning: trait objects without an explicit `dyn` are deprecated
[INFO] [stderr]   --> src/lib.rs:73:44
[INFO] [stderr]    |
[INFO] [stderr] 73 | pub type StringTreeOption<'a> = Option<&'a StringTree>;
[INFO] [stderr]    |                                            ^^^^^^^^^^
[INFO] [stderr]    |
[INFO] [stderr]    = warning: this is accepted in the current edition (Rust 2015) but is a hard error in Rust 2021!
[INFO] [stderr]    = note: for more information, see <https://doc.rust-lang.org/edition-guide/rust-2021/warnings-promoted-to-error.html>
[INFO] [stderr]    = note: `#[warn(bare_trait_objects)]` (part of `#[warn(rust_2021_compatibility)]`) on by default
[INFO] [stderr] help: if this is a dyn-compatible trait, use `dyn`
[INFO] [stderr]    |
[INFO] [stderr] 73 | pub type StringTreeOption<'a> = Option<&'a dyn StringTree>;
[INFO] [stderr]    |                                            +++
[INFO] [stderr] 
[INFO] [stderr] warning: trait objects without an explicit `dyn` are deprecated
[INFO] [stderr]   --> src/lib.rs:84:29
[INFO] [stderr]    |
[INFO] [stderr] 84 | pub type StringTreeFn = Box<Fn() -> &'static str>;
[INFO] [stderr]    |                             ^^^^^^^^^^^^^^^^^^^^
[INFO] [stderr]    |
[INFO] [stderr]    = warning: this is accepted in the current edition (Rust 2015) but is a hard error in Rust 2021!
[INFO] [stderr]    = note: for more information, see <https://doc.rust-lang.org/edition-guide/rust-2021/warnings-promoted-to-error.html>
[INFO] [stderr] help: if this is a dyn-compatible trait, use `dyn`
[INFO] [stderr]    |
[INFO] [stderr] 84 | pub type StringTreeFn = Box<dyn Fn() -> &'static str>;
[INFO] [stderr]    |                             +++
[INFO] [stderr] 
[INFO] [stderr] warning: trait objects without an explicit `dyn` are deprecated
[INFO] [stderr]   --> src/lib.rs:13:6
[INFO] [stderr]    |
[INFO] [stderr] 13 | impl StringTree {
[INFO] [stderr]    |      ^^^^^^^^^^
[INFO] [stderr]    |
[INFO] [stderr]    = warning: this is accepted in the current edition (Rust 2015) but is a hard error in Rust 2021!
[INFO] [stderr]    = note: for more information, see <https://doc.rust-lang.org/edition-guide/rust-2021/warnings-promoted-to-error.html>
[INFO] [stderr] help: if this is a dyn-compatible trait, use `dyn`
[INFO] [stderr]    |
[INFO] [stderr] 13 | impl dyn StringTree {
[INFO] [stderr]    |      +++
[INFO] [stderr] help: you might have intended to implement this trait for a given type
[INFO] [stderr]    |
[INFO] [stderr] 13 | impl StringTree for /* Type */ {
[INFO] [stderr]    |                 ++++++++++++++
[INFO] [stderr] 
[INFO] [stderr] warning: trait objects without an explicit `dyn` are deprecated
[INFO] [stderr]   --> src/lib.rs:14:22
[INFO] [stderr]    |
[INFO] [stderr] 14 |     pub fn new(s: &[&StringTree]) -> StringTreeBuf {
[INFO] [stderr]    |                      ^^^^^^^^^^
[INFO] [stderr]    |
[INFO] [stderr]    = warning: this is accepted in the current edition (Rust 2015) but is a hard error in Rust 2021!
[INFO] [stderr]    = note: for more information, see <https://doc.rust-lang.org/edition-guide/rust-2021/warnings-promoted-to-error.html>
[INFO] [stderr] help: if this is a dyn-compatible trait, use `dyn`
[INFO] [stderr]    |
[INFO] [stderr] 14 |     pub fn new(s: &[&dyn StringTree]) -> StringTreeBuf {
[INFO] [stderr]    |                      +++
[INFO] [stderr] 
[INFO] [stderr] warning: `stringtree` (lib) generated 4 warnings (run `cargo fix --lib -p stringtree` to apply 4 suggestions)
[INFO] [stderr] warning: trait objects without an explicit `dyn` are deprecated
[INFO] [stderr]   --> src/lib.rs:99:18
[INFO] [stderr]    |
[INFO] [stderr] 99 |         let i0 = StringTree::indent(&"x");
[INFO] [stderr]    |                  ^^^^^^^^^^
[INFO] [stderr]    |
[INFO] [stderr]    = warning: this is accepted in the current edition (Rust 2015) but is a hard error in Rust 2021!
[INFO] [stderr]    = note: for more information, see <https://doc.rust-lang.org/edition-guide/rust-2021/warnings-promoted-to-error.html>
[INFO] [stderr] help: if this is a dyn-compatible trait, use `dyn`
[INFO] [stderr]    |
[INFO] [stderr] 99 |         let i0 = <dyn StringTree>::indent(&"x");
[INFO] [stderr]    |                  ++++           +
[INFO] [stderr] 
[INFO] [stderr] warning: trait objects without an explicit `dyn` are deprecated
[INFO] [stderr]    --> src/lib.rs:112:20
[INFO] [stderr]     |
[INFO] [stderr] 112 |         assert_eq!(StringTree::new(&[]).to_string(), "");
[INFO] [stderr]     |                    ^^^^^^^^^^
[INFO] [stderr]     |
[INFO] [stderr]     = warning: this is accepted in the current edition (Rust 2015) but is a hard error in Rust 2021!
[INFO] [stderr]     = note: for more information, see <https://doc.rust-lang.org/edition-guide/rust-2021/warnings-promoted-to-error.html>
[INFO] [stderr] help: if this is a dyn-compatible trait, use `dyn`
[INFO] [stderr]     |
[INFO] [stderr] 112 |         assert_eq!(<dyn StringTree>::new(&[]).to_string(), "");
[INFO] [stderr]     |                    ++++           +
[INFO] [stderr] 
[INFO] [stderr] warning: trait objects without an explicit `dyn` are deprecated
[INFO] [stderr]    --> src/lib.rs:113:20
[INFO] [stderr]     |
[INFO] [stderr] 113 |         assert_eq!(StringTree::new(&[&"foo"]).to_string(), "foo");
[INFO] [stderr]     |                    ^^^^^^^^^^
[INFO] [stderr]     |
[INFO] [stderr]     = warning: this is accepted in the current edition (Rust 2015) but is a hard error in Rust 2021!
[INFO] [stderr]     = note: for more information, see <https://doc.rust-lang.org/edition-guide/rust-2021/warnings-promoted-to-error.html>
[INFO] [stderr] help: if this is a dyn-compatible trait, use `dyn`
[INFO] [stderr]     |
[INFO] [stderr] 113 |         assert_eq!(<dyn StringTree>::new(&[&"foo"]).to_string(), "foo");
[INFO] [stderr]     |                    ++++           +
[INFO] [stderr] 
[INFO] [stderr] warning: trait objects without an explicit `dyn` are deprecated
[INFO] [stderr]    --> src/lib.rs:114:20
[INFO] [stderr]     |
[INFO] [stderr] 114 |         assert_eq!(StringTree::new(&[&"foo", &"bar"]).to_string(), "foobar");
[INFO] [stderr]     |                    ^^^^^^^^^^
[INFO] [stderr]     |
[INFO] [stderr]     = warning: this is accepted in the current edition (Rust 2015) but is a hard error in Rust 2021!
[INFO] [stderr]     = note: for more information, see <https://doc.rust-lang.org/edition-guide/rust-2021/warnings-promoted-to-error.html>
[INFO] [stderr] help: if this is a dyn-compatible trait, use `dyn`
[INFO] [stderr]     |
[INFO] [stderr] 114 |         assert_eq!(<dyn StringTree>::new(&[&"foo", &"bar"]).to_string(), "foobar");
[INFO] [stderr]     |                    ++++           +
[INFO] [stderr] 
[INFO] [stderr] warning: trait objects without an explicit `dyn` are deprecated
[INFO] [stderr]    --> src/lib.rs:116:18
[INFO] [stderr]     |
[INFO] [stderr] 116 |         let i2 = StringTree::indent("x").next().next();
[INFO] [stderr]     |                  ^^^^^^^^^^
[INFO] [stderr]     |
[INFO] [stderr]     = warning: this is accepted in the current edition (Rust 2015) but is a hard error in Rust 2021!
[INFO] [stderr]     = note: for more information, see <https://doc.rust-lang.org/edition-guide/rust-2021/warnings-promoted-to-error.html>
[INFO] [stderr] help: if this is a dyn-compatible trait, use `dyn`
[INFO] [stderr]     |
[INFO] [stderr] 116 |         let i2 = <dyn StringTree>::indent("x").next().next();
[INFO] [stderr]     |                  ++++           +
[INFO] [stderr] 
[INFO] [stderr] warning: trait objects without an explicit `dyn` are deprecated
[INFO] [stderr]    --> src/lib.rs:117:20
[INFO] [stderr]     |
[INFO] [stderr] 117 |         assert_eq!(StringTree::new(&[&i2, &"bar"]).to_string(), "xxbar");
[INFO] [stderr]     |                    ^^^^^^^^^^
[INFO] [stderr]     |
[INFO] [stderr]     = warning: this is accepted in the current edition (Rust 2015) but is a hard error in Rust 2021!
[INFO] [stderr]     = note: for more information, see <https://doc.rust-lang.org/edition-guide/rust-2021/warnings-promoted-to-error.html>
[INFO] [stderr] help: if this is a dyn-compatible trait, use `dyn`
[INFO] [stderr]     |
[INFO] [stderr] 117 |         assert_eq!(<dyn StringTree>::new(&[&i2, &"bar"]).to_string(), "xxbar");
[INFO] [stderr]     |                    ++++           +
[INFO] [stderr] 
[INFO] [stderr] warning: trait objects without an explicit `dyn` are deprecated
[INFO] [stderr]    --> src/lib.rs:120:20
[INFO] [stderr]     |
[INFO] [stderr] 120 |         assert_eq!(StringTree::new(&[&f]).to_string(), "foo");
[INFO] [stderr]     |                    ^^^^^^^^^^
[INFO] [stderr]     |
[INFO] [stderr]     = warning: this is accepted in the current edition (Rust 2015) but is a hard error in Rust 2021!
[INFO] [stderr]     = note: for more information, see <https://doc.rust-lang.org/edition-guide/rust-2021/warnings-promoted-to-error.html>
[INFO] [stderr] help: if this is a dyn-compatible trait, use `dyn`
[INFO] [stderr]     |
[INFO] [stderr] 120 |         assert_eq!(<dyn StringTree>::new(&[&f]).to_string(), "foo");
[INFO] [stderr]     |                    ++++           +
[INFO] [stderr] 
[INFO] [stderr] warning: trait objects without an explicit `dyn` are deprecated
[INFO] [stderr]    --> src/lib.rs:121:20
[INFO] [stderr]     |
[INFO] [stderr] 121 |         assert_eq!(StringTree::new(&[&"bar", &f]).to_string(), "barfoo");
[INFO] [stderr]     |                    ^^^^^^^^^^
[INFO] [stderr]     |
[INFO] [stderr]     = warning: this is accepted in the current edition (Rust 2015) but is a hard error in Rust 2021!
[INFO] [stderr]     = note: for more information, see <https://doc.rust-lang.org/edition-guide/rust-2021/warnings-promoted-to-error.html>
[INFO] [stderr] help: if this is a dyn-compatible trait, use `dyn`
[INFO] [stderr]     |
[INFO] [stderr] 121 |         assert_eq!(<dyn StringTree>::new(&[&"bar", &f]).to_string(), "barfoo");
[INFO] [stderr]     |                    ++++           +
[INFO] [stderr] 
[INFO] [stderr] warning: trait objects without an explicit `dyn` are deprecated
[INFO] [stderr]    --> src/lib.rs:124:17
[INFO] [stderr]     |
[INFO] [stderr] 124 |         let c: &StringTree = &StringTree::new(&[&"opt"]);
[INFO] [stderr]     |                 ^^^^^^^^^^
[INFO] [stderr]     |
[INFO] [stderr]     = warning: this is accepted in the current edition (Rust 2015) but is a hard error in Rust 2021!
[INFO] [stderr]     = note: for more information, see <https://doc.rust-lang.org/edition-guide/rust-2021/warnings-promoted-to-error.html>
[INFO] [stderr] help: if this is a dyn-compatible trait, use `dyn`
[INFO] [stderr]     |
[INFO] [stderr] 124 |         let c: &dyn StringTree = &StringTree::new(&[&"opt"]);
[INFO] [stderr]     |                 +++
[INFO] [stderr] 
[INFO] [stderr] warning: trait objects without an explicit `dyn` are deprecated
[INFO] [stderr]    --> src/lib.rs:124:31
[INFO] [stderr]     |
[INFO] [stderr] 124 |         let c: &StringTree = &StringTree::new(&[&"opt"]);
[INFO] [stderr]     |                               ^^^^^^^^^^
[INFO] [stderr]     |
[INFO] [stderr]     = warning: this is accepted in the current edition (Rust 2015) but is a hard error in Rust 2021!
[INFO] [stderr]     = note: for more information, see <https://doc.rust-lang.org/edition-guide/rust-2021/warnings-promoted-to-error.html>
[INFO] [stderr] help: if this is a dyn-compatible trait, use `dyn`
[INFO] [stderr]     |
[INFO] [stderr] 124 |         let c: &StringTree = &<dyn StringTree>::new(&[&"opt"]);
[INFO] [stderr]     |                               ++++           +
[INFO] [stderr] 
[INFO] [stderr] warning: trait objects without an explicit `dyn` are deprecated
[INFO] [stderr]    --> src/lib.rs:126:20
[INFO] [stderr]     |
[INFO] [stderr] 126 |         assert_eq!(StringTree::new(&[&none]).to_string(), "");
[INFO] [stderr]     |                    ^^^^^^^^^^
[INFO] [stderr]     |
[INFO] [stderr]     = warning: this is accepted in the current edition (Rust 2015) but is a hard error in Rust 2021!
[INFO] [stderr]     = note: for more information, see <https://doc.rust-lang.org/edition-guide/rust-2021/warnings-promoted-to-error.html>
[INFO] [stderr] help: if this is a dyn-compatible trait, use `dyn`
[INFO] [stderr]     |
[INFO] [stderr] 126 |         assert_eq!(<dyn StringTree>::new(&[&none]).to_string(), "");
[INFO] [stderr]     |                    ++++           +
[INFO] [stderr] 
[INFO] [stderr] warning: trait objects without an explicit `dyn` are deprecated
[INFO] [stderr]    --> src/lib.rs:127:20
[INFO] [stderr]     |
[INFO] [stderr] 127 |         assert_eq!(StringTree::new(&[&some]).to_string(), "opt");
[INFO] [stderr]     |                    ^^^^^^^^^^
[INFO] [stderr]     |
[INFO] [stderr]     = warning: this is accepted in the current edition (Rust 2015) but is a hard error in Rust 2021!
[INFO] [stderr]     = note: for more information, see <https://doc.rust-lang.org/edition-guide/rust-2021/warnings-promoted-to-error.html>
[INFO] [stderr] help: if this is a dyn-compatible trait, use `dyn`
[INFO] [stderr]     |
[INFO] [stderr] 127 |         assert_eq!(<dyn StringTree>::new(&[&some]).to_string(), "opt");
[INFO] [stderr]     |                    ++++           +
[INFO] [stderr] 
[INFO] [stderr] warning: trait objects without an explicit `dyn` are deprecated
[INFO] [stderr]    --> src/lib.rs:128:20
[INFO] [stderr]     |
[INFO] [stderr] 128 |         assert_eq!(StringTree::new(&[&"foo", &none, &some]).to_string(), "fooopt");
[INFO] [stderr]     |                    ^^^^^^^^^^
[INFO] [stderr]     |
[INFO] [stderr]     = warning: this is accepted in the current edition (Rust 2015) but is a hard error in Rust 2021!
[INFO] [stderr]     = note: for more information, see <https://doc.rust-lang.org/edition-guide/rust-2021/warnings-promoted-to-error.html>
[INFO] [stderr] help: if this is a dyn-compatible trait, use `dyn`
[INFO] [stderr]     |
[INFO] [stderr] 128 |         assert_eq!(<dyn StringTree>::new(&[&"foo", &none, &some]).to_string(), "fooopt");
[INFO] [stderr]     |                    ++++           +
[INFO] [stderr] 
[INFO] [stderr] warning: `stringtree` (lib test) generated 17 warnings (4 duplicates) (run `cargo fix --lib -p stringtree --tests` to apply 13 suggestions)
[INFO] [stderr]     Finished `test` profile [unoptimized + debuginfo] target(s) in 0.05s
[INFO] [stderr]      Running unittests src/lib.rs (/opt/rustwide/target/debug/deps/stringtree-500c5f09e0c59a2c)
[INFO] [stdout] 
[INFO] [stdout] running 2 tests
[INFO] [stdout] test test::test_stringtree_new ... ok
[INFO] [stdout] test test::test_stringtree_indent ... ok
[INFO] [stdout] 
[INFO] [stdout] test result: ok. 2 passed; 0 failed; 0 ignored; 0 measured; 0 filtered out; finished in 0.00s
[INFO] [stdout] 
[INFO] [stderr]    Doc-tests stringtree
[INFO] [stdout] 
[INFO] [stdout] running 0 tests
[INFO] [stdout] 
[INFO] [stdout] test result: ok. 0 passed; 0 failed; 0 ignored; 0 measured; 0 filtered out; finished in 0.00s
[INFO] [stdout] 
[INFO] running `Command { std: "docker" "inspect" "7c781bc473e85c8133e60fa98e9dd589819bf5fb9d5835c3473ebad5cd8c190d", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "7c781bc473e85c8133e60fa98e9dd589819bf5fb9d5835c3473ebad5cd8c190d", kill_on_drop: false }`
[INFO] [stdout] 7c781bc473e85c8133e60fa98e9dd589819bf5fb9d5835c3473ebad5cd8c190d
