[INFO] cloning repository https://github.com/paavohuhtala/bfcrs
[INFO] running `Command { std: "git" "-c" "credential.helper=" "-c" "credential.helper=/workspace/cargo-home/bin/git-credential-null" "clone" "--bare" "https://github.com/paavohuhtala/bfcrs" "/workspace/cache/git-repos/https%3A%2F%2Fgithub.com%2Fpaavohuhtala%2Fbfcrs", kill_on_drop: false }`
[INFO] [stderr] Cloning into bare repository '/workspace/cache/git-repos/https%3A%2F%2Fgithub.com%2Fpaavohuhtala%2Fbfcrs'...
[INFO] running `Command { std: "git" "rev-parse" "HEAD", kill_on_drop: false }`
[INFO] [stdout] cfa75356188b83ce56b1de13366bd431c304cfa2
[INFO] testing paavohuhtala/bfcrs against beta-2021-08-01 for beta-1.55-1
[INFO] running `Command { std: "git" "clone" "/workspace/cache/git-repos/https%3A%2F%2Fgithub.com%2Fpaavohuhtala%2Fbfcrs" "/workspace/builds/worker-4/source", kill_on_drop: false }`
[INFO] [stderr] Cloning into '/workspace/builds/worker-4/source'...
[INFO] [stderr] done.
[INFO] validating manifest of git repo https://github.com/paavohuhtala/bfcrs on toolchain beta-2021-08-01
[INFO] running `Command { std: "/workspace/cargo-home/bin/cargo" "+beta-2021-08-01" "metadata" "--manifest-path" "Cargo.toml" "--no-deps", kill_on_drop: false }`
[INFO] started tweaking git repo https://github.com/paavohuhtala/bfcrs
[INFO] finished tweaking git repo https://github.com/paavohuhtala/bfcrs
[INFO] tweaked toml for git repo https://github.com/paavohuhtala/bfcrs written to /workspace/builds/worker-4/source/Cargo.toml
[INFO] crate git repo https://github.com/paavohuhtala/bfcrs already has a lockfile, it will not be regenerated
[INFO] running `Command { std: "/workspace/cargo-home/bin/cargo" "+beta-2021-08-01" "fetch" "--manifest-path" "Cargo.toml", kill_on_drop: false }`
[INFO] [stderr]  Downloading crates ...
[INFO] [stderr]   Downloaded leb128 v0.2.3
[INFO] running `Command { std: "docker" "create" "-v" "/var/lib/crater-agent-workspace/builds/worker-4/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-4/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@sha256:34b6a614d2c27851fe6cbf88fbd1137609cefab8b10d0615aaeb6fd47975d74e" "/opt/rustwide/cargo-home/bin/cargo" "+beta-2021-08-01" "metadata" "--no-deps" "--format-version=1", kill_on_drop: false }`
[INFO] [stdout] e95b0e77a252acc3657460b722d58c9ea3d3591cf93167a4dcfd9c07f1c9f50e
[INFO] running `Command { std: "docker" "start" "-a" "e95b0e77a252acc3657460b722d58c9ea3d3591cf93167a4dcfd9c07f1c9f50e", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "inspect" "e95b0e77a252acc3657460b722d58c9ea3d3591cf93167a4dcfd9c07f1c9f50e", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "e95b0e77a252acc3657460b722d58c9ea3d3591cf93167a4dcfd9c07f1c9f50e", kill_on_drop: false }`
[INFO] [stdout] e95b0e77a252acc3657460b722d58c9ea3d3591cf93167a4dcfd9c07f1c9f50e
[INFO] running `Command { std: "docker" "create" "-v" "/var/lib/crater-agent-workspace/builds/worker-4/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-4/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@sha256:34b6a614d2c27851fe6cbf88fbd1137609cefab8b10d0615aaeb6fd47975d74e" "/opt/rustwide/cargo-home/bin/cargo" "+beta-2021-08-01" "build" "--frozen" "--message-format=json", kill_on_drop: false }`
[INFO] [stdout] d476e29bad7ebd36972d878aa94ab15947334d20354a656af6967937edc71952
[INFO] running `Command { std: "docker" "start" "-a" "d476e29bad7ebd36972d878aa94ab15947334d20354a656af6967937edc71952", kill_on_drop: false }`
[INFO] [stderr]    Compiling leb128 v0.2.3
[INFO] [stderr]    Compiling bfcrs v0.1.0 (/opt/rustwide/workdir)
[INFO] [stdout] error[E0425]: cannot find value `tail` in this scope
[INFO] [stdout]   --> src/optimizer.rs:13:45
[INFO] [stdout]    |
[INFO] [stdout] 13 |       (Some(ChangeAddr(a)), [ChangeAddr(b), tail..]) => (Some(ChangeAddr(a + b)), tail),
[INFO] [stdout]    |                                             ^^^^ not found in this scope
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] error[E0425]: cannot find value `tail` in this scope
[INFO] [stdout]   --> src/optimizer.rs:13:83
[INFO] [stdout]    |
[INFO] [stdout] 13 |       (Some(ChangeAddr(a)), [ChangeAddr(b), tail..]) => (Some(ChangeAddr(a + b)), tail),
[INFO] [stdout]    |                                                                                   ^^^^ not found in this scope
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] error[E0425]: cannot find value `tail` in this scope
[INFO] [stdout]   --> src/optimizer.rs:14:79
[INFO] [stdout]    |
[INFO] [stdout] 14 |       (Some(Offset(offs_a, ChangeValue(a))), [Offset(offs_b, ChangeValue(b)), tail..])
[INFO] [stdout]    |                                                                               ^^^^ not found in this scope
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] error[E0425]: cannot find value `tail` in this scope
[INFO] [stdout]   --> src/optimizer.rs:17:65
[INFO] [stdout]    |
[INFO] [stdout] 17 |         (Some(ProgramToken::offs_change_value(*offs_a, a + b)), tail)
[INFO] [stdout]    |                                                                 ^^^^ not found in this scope
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] error[E0425]: cannot find value `tail` in this scope
[INFO] [stdout]   --> src/optimizer.rs:21:68
[INFO] [stdout]    |
[INFO] [stdout] 21 |         [Offset(0, ChangeValue(value)), ChangeAddr(addr_offset_b), tail..],
[INFO] [stdout]    |                                                                    ^^^^ not found in this scope
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] error[E0425]: cannot find value `tail` in this scope
[INFO] [stdout]   --> src/optimizer.rs:27:11
[INFO] [stdout]    |
[INFO] [stdout] 27 |           tail,
[INFO] [stdout]    |           ^^^^ not found in this scope
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] error[E0425]: cannot find value `tail` in this scope
[INFO] [stdout]   --> src/optimizer.rs:38:20
[INFO] [stdout]    |
[INFO] [stdout] 38 |             [head, tail..] => (Some(head.clone()), tail),
[INFO] [stdout]    |                    ^^^^ not found in this scope
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] error[E0425]: cannot find value `tail` in this scope
[INFO] [stdout]   --> src/optimizer.rs:38:52
[INFO] [stdout]    |
[INFO] [stdout] 38 |             [head, tail..] => (Some(head.clone()), tail),
[INFO] [stdout]    |                                                    ^^^^ not found in this scope
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] error[E0425]: cannot find value `tail` in this scope
[INFO] [stdout]   --> src/optimizer.rs:42:76
[INFO] [stdout]    |
[INFO] [stdout] 42 |       (Some(Offset(offs_a, SetValue(0))), [Offset(offs_b, ChangeValue(a)), tail..])
[INFO] [stdout]    |                                                                            ^^^^ not found in this scope
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] error[E0425]: cannot find value `tail` in this scope
[INFO] [stdout]   --> src/optimizer.rs:45:59
[INFO] [stdout]    |
[INFO] [stdout] 45 |         (Some(ProgramToken::offs_set_value(*offs_a, *a)), tail)
[INFO] [stdout]    |                                                           ^^^^ not found in this scope
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] error[E0425]: cannot find value `tail` in this scope
[INFO] [stdout]   --> src/optimizer.rs:47:73
[INFO] [stdout]    |
[INFO] [stdout] 47 |       (Some(Offset(offs_a, SetValue(_))), [Offset(offs_b, SetValue(a)), tail..])
[INFO] [stdout]    |                                                                         ^^^^ not found in this scope
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] error[E0425]: cannot find value `tail` in this scope
[INFO] [stdout]   --> src/optimizer.rs:48:78
[INFO] [stdout]    |
[INFO] [stdout] 48 |       | (Some(Offset(offs_a, ChangeValue(_))), [Offset(offs_b, SetValue(a)), tail..])
[INFO] [stdout]    |                                                                              ^^^^ not found in this scope
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] error[E0425]: cannot find value `tail` in this scope
[INFO] [stdout]   --> src/optimizer.rs:51:59
[INFO] [stdout]    |
[INFO] [stdout] 51 |         (Some(ProgramToken::offs_set_value(*offs_a, *a)), tail)
[INFO] [stdout]    |                                                           ^^^^ not found in this scope
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] error[E0425]: cannot find value `tail` in this scope
[INFO] [stdout]   --> src/optimizer.rs:58:32
[INFO] [stdout]    |
[INFO] [stdout] 58 |       (Some(ref token), [head, tail..]) => {
[INFO] [stdout]    |                                ^^^^ not found in this scope
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] error[E0425]: cannot find value `tail` in this scope
[INFO] [stdout]   --> src/optimizer.rs:60:30
[INFO] [stdout]    |
[INFO] [stdout] 60 |         (Some(head.clone()), tail)
[INFO] [stdout]    |                              ^^^^ not found in this scope
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] error[E0425]: cannot find value `tail` in this scope
[INFO] [stdout]   --> src/optimizer.rs:62:21
[INFO] [stdout]    |
[INFO] [stdout] 62 |       (None, [head, tail..]) => (Some(head.clone()), tail),
[INFO] [stdout]    |                     ^^^^ not found in this scope
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] error[E0425]: cannot find value `tail` in this scope
[INFO] [stdout]   --> src/optimizer.rs:62:54
[INFO] [stdout]    |
[INFO] [stdout] 62 |       (None, [head, tail..]) => (Some(head.clone()), tail),
[INFO] [stdout]    |                                                      ^^^^ not found in this scope
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] error[E0554]: `#![feature]` may not be used on the beta release channel
[INFO] [stdout]  --> src/lib.rs:1:1
[INFO] [stdout]   |
[INFO] [stdout] 1 | #![feature(iterator_find_map)]
[INFO] [stdout]   | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] error[E0554]: `#![feature]` may not be used on the beta release channel
[INFO] [stdout]  --> src/lib.rs:2:1
[INFO] [stdout]   |
[INFO] [stdout] 2 | #![feature(iterator_flatten)]
[INFO] [stdout]   | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] error[E0554]: `#![feature]` may not be used on the beta release channel
[INFO] [stdout]  --> src/lib.rs:3:1
[INFO] [stdout]   |
[INFO] [stdout] 3 | #![feature(slice_patterns)]
[INFO] [stdout]   | ^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: remove the attribute
[INFO] [stdout]   |
[INFO] [stdout]   = help: the feature `slice_patterns` has been stable since 1.42.0 and no longer requires an attribute to enable
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] error[E0658]: `X..` patterns in slices are experimental
[INFO] [stdout]   --> src/optimizer.rs:13:45
[INFO] [stdout]    |
[INFO] [stdout] 13 |       (Some(ChangeAddr(a)), [ChangeAddr(b), tail..]) => (Some(ChangeAddr(a + b)), tail),
[INFO] [stdout]    |                                             ^^^^^^
[INFO] [stdout]    |
[INFO] [stdout]    = note: see issue #67264 <https://github.com/rust-lang/rust/issues/67264> for more information
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] error[E0658]: `X..` patterns in slices are experimental
[INFO] [stdout]   --> src/optimizer.rs:14:79
[INFO] [stdout]    |
[INFO] [stdout] 14 |       (Some(Offset(offs_a, ChangeValue(a))), [Offset(offs_b, ChangeValue(b)), tail..])
[INFO] [stdout]    |                                                                               ^^^^^^
[INFO] [stdout]    |
[INFO] [stdout]    = note: see issue #67264 <https://github.com/rust-lang/rust/issues/67264> for more information
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] error[E0658]: `X..` patterns in slices are experimental
[INFO] [stdout]   --> src/optimizer.rs:21:68
[INFO] [stdout]    |
[INFO] [stdout] 21 |         [Offset(0, ChangeValue(value)), ChangeAddr(addr_offset_b), tail..],
[INFO] [stdout]    |                                                                    ^^^^^^
[INFO] [stdout]    |
[INFO] [stdout]    = note: see issue #67264 <https://github.com/rust-lang/rust/issues/67264> for more information
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] error[E0658]: `X..` patterns in slices are experimental
[INFO] [stdout]   --> src/optimizer.rs:38:20
[INFO] [stdout]    |
[INFO] [stdout] 38 |             [head, tail..] => (Some(head.clone()), tail),
[INFO] [stdout]    |                    ^^^^^^
[INFO] [stdout]    |
[INFO] [stdout]    = note: see issue #67264 <https://github.com/rust-lang/rust/issues/67264> for more information
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] error[E0658]: `X..` patterns in slices are experimental
[INFO] [stdout]   --> src/optimizer.rs:42:76
[INFO] [stdout]    |
[INFO] [stdout] 42 |       (Some(Offset(offs_a, SetValue(0))), [Offset(offs_b, ChangeValue(a)), tail..])
[INFO] [stdout]    |                                                                            ^^^^^^
[INFO] [stdout]    |
[INFO] [stdout]    = note: see issue #67264 <https://github.com/rust-lang/rust/issues/67264> for more information
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] error[E0658]: `X..` patterns in slices are experimental
[INFO] [stdout]   --> src/optimizer.rs:47:73
[INFO] [stdout]    |
[INFO] [stdout] 47 |       (Some(Offset(offs_a, SetValue(_))), [Offset(offs_b, SetValue(a)), tail..])
[INFO] [stdout]    |                                                                         ^^^^^^
[INFO] [stdout]    |
[INFO] [stdout]    = note: see issue #67264 <https://github.com/rust-lang/rust/issues/67264> for more information
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] error[E0658]: `X..` patterns in slices are experimental
[INFO] [stdout]   --> src/optimizer.rs:48:78
[INFO] [stdout]    |
[INFO] [stdout] 48 |       | (Some(Offset(offs_a, ChangeValue(_))), [Offset(offs_b, SetValue(a)), tail..])
[INFO] [stdout]    |                                                                              ^^^^^^
[INFO] [stdout]    |
[INFO] [stdout]    = note: see issue #67264 <https://github.com/rust-lang/rust/issues/67264> for more information
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] error[E0658]: `X..` patterns in slices are experimental
[INFO] [stdout]   --> src/optimizer.rs:58:32
[INFO] [stdout]    |
[INFO] [stdout] 58 |       (Some(ref token), [head, tail..]) => {
[INFO] [stdout]    |                                ^^^^^^
[INFO] [stdout]    |
[INFO] [stdout]    = note: see issue #67264 <https://github.com/rust-lang/rust/issues/67264> for more information
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] error[E0658]: `X..` patterns in slices are experimental
[INFO] [stdout]   --> src/optimizer.rs:62:21
[INFO] [stdout]    |
[INFO] [stdout] 62 |       (None, [head, tail..]) => (Some(head.clone()), tail),
[INFO] [stdout]    |                     ^^^^^^
[INFO] [stdout]    |
[INFO] [stdout]    = note: see issue #67264 <https://github.com/rust-lang/rust/issues/67264> for more information
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: trait objects without an explicit `dyn` are deprecated
[INFO] [stdout]   --> src/backend/wasm/code_stream.rs:85:66
[INFO] [stdout]    |
[INFO] [stdout] 85 |   pub fn emit_print_string(&mut self, s: &str) -> Result<(), Box<Error>> {
[INFO] [stdout]    |                                                                  ^^^^^ help: use `dyn`: `dyn Error`
[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 issue #80165 <https://github.com/rust-lang/rust/issues/80165>
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: trait objects without an explicit `dyn` are deprecated
[INFO] [stdout]   --> src/backend/wasm/code_stream.rs:93:61
[INFO] [stdout]    |
[INFO] [stdout] 93 |   pub fn emit(&mut self, op: Instruction) -> Result<(), Box<Error>> {
[INFO] [stdout]    |                                                             ^^^^^ help: use `dyn`: `dyn Error`
[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 issue #80165 <https://github.com/rust-lang/rust/issues/80165>
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: trait objects without an explicit `dyn` are deprecated
[INFO] [stdout]   --> src/backend/wasm/module_builder.rs:29:56
[INFO] [stdout]    |
[INFO] [stdout] 29 |   pub fn add_section(&mut self, id: u8, entries: &[Box<Fn(&mut dyn Write) -> ()>]) {
[INFO] [stdout]    |                                                        ^^^^^^^^^^^^^^^^^^^^^^^^ help: use `dyn`: `dyn Fn(&mut dyn Write) -> ()`
[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 issue #80165 <https://github.com/rust-lang/rust/issues/80165>
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: trait objects without an explicit `dyn` are deprecated
[INFO] [stdout]   --> src/backend/wasm/module_builder.rs:40:82
[INFO] [stdout]    |
[INFO] [stdout] 40 |   pub fn write_to_stream(mut self, mut stream: &mut dyn Write) -> Result<(), Box<Error>> {
[INFO] [stdout]    |                                                                                  ^^^^^ help: use `dyn`: `dyn Error`
[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 issue #80165 <https://github.com/rust-lang/rust/issues/80165>
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: trait objects without an explicit `dyn` are deprecated
[INFO] [stdout]   --> src/backend/wasm/module_builder.rs:66:21
[INFO] [stdout]    |
[INFO] [stdout] 66 | ) -> Result<(), Box<Error>> {
[INFO] [stdout]    |                     ^^^^^ help: use `dyn`: `dyn Error`
[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 issue #80165 <https://github.com/rust-lang/rust/issues/80165>
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: trait objects without an explicit `dyn` are deprecated
[INFO] [stdout]    --> src/backend/wasm/module_builder.rs:321:23
[INFO] [stdout]     |
[INFO] [stdout] 321 |   ) -> Result<(), Box<Error>> {
[INFO] [stdout]     |                       ^^^^^ help: use `dyn`: `dyn Error`
[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 issue #80165 <https://github.com/rust-lang/rust/issues/80165>
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: trait objects without an explicit `dyn` are deprecated
[INFO] [stdout]   --> src/backend/mod.rs:12:6
[INFO] [stdout]    |
[INFO] [stdout] 12 | impl Backend {
[INFO] [stdout]    |      ^^^^^^^ help: use `dyn`: `dyn Backend`
[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 issue #80165 <https://github.com/rust-lang/rust/issues/80165>
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: trait objects without an explicit `dyn` are deprecated
[INFO] [stdout]   --> src/backend/mod.rs:13:46
[INFO] [stdout]    |
[INFO] [stdout] 13 |   pub fn from_name(name: &str) -> Option<Box<Backend>> {
[INFO] [stdout]    |                                              ^^^^^^^ help: use `dyn`: `dyn Backend`
[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 issue #80165 <https://github.com/rust-lang/rust/issues/80165>
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] error: aborting due to 29 previous errors; 8 warnings emitted
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stderr] error: could not compile `bfcrs` due to 30 previous errors; 8 warnings emitted
[INFO] [stdout] Some errors have detailed explanations: E0425, E0554, E0658.
[INFO] [stdout] 
[INFO] [stdout] For more information about an error, try `rustc --explain E0425`.
[INFO] [stdout] 
[INFO] running `Command { std: "docker" "inspect" "d476e29bad7ebd36972d878aa94ab15947334d20354a656af6967937edc71952", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "d476e29bad7ebd36972d878aa94ab15947334d20354a656af6967937edc71952", kill_on_drop: false }`
[INFO] [stdout] d476e29bad7ebd36972d878aa94ab15947334d20354a656af6967937edc71952
