[INFO] fetching crate rotor-tools 0.3.2...
[INFO] building rotor-tools-0.3.2 against try#4987e9d4227139400384ab59296ffee3b0fb1183 for pr-146237-2
[INFO] extracting crate rotor-tools 0.3.2 into /workspace/builds/worker-3-tc2/source
[INFO] started tweaking crates.io crate rotor-tools 0.3.2
[INFO] finished tweaking crates.io crate rotor-tools 0.3.2
[INFO] tweaked toml for crates.io crate rotor-tools 0.3.2 written to /workspace/builds/worker-3-tc2/source/Cargo.toml
[INFO] validating manifest of crates.io crate rotor-tools 0.3.2 on toolchain 4987e9d4227139400384ab59296ffee3b0fb1183
[INFO] running `Command { std: CARGO_HOME="/workspace/cargo-home" RUSTUP_HOME="/workspace/rustup-home" "/workspace/cargo-home/bin/cargo" "+4987e9d4227139400384ab59296ffee3b0fb1183" "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" "+4987e9d4227139400384ab59296ffee3b0fb1183" "generate-lockfile" "--manifest-path" "Cargo.toml", kill_on_drop: false }`
[INFO] [stderr]     Updating crates.io index
[INFO] [stderr]      Locking 23 packages to latest compatible versions
[INFO] [stderr]       Adding wasi v0.10.0+wasi-snapshot-preview1 (available: v0.10.2+wasi-snapshot-preview1)
[INFO] running `Command { std: CARGO_HOME="/workspace/cargo-home" RUSTUP_HOME="/workspace/rustup-home" "/workspace/cargo-home/bin/cargo" "+4987e9d4227139400384ab59296ffee3b0fb1183" "fetch" "--manifest-path" "Cargo.toml", kill_on_drop: false }`
[INFO] [stderr] warning: no edition set: defaulting to the 2015 edition while the latest is 2024
[INFO] running `Command { std: "docker" "create" "-v" "/var/lib/crater-agent-workspace/builds/worker-3-tc2/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-3-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:e90291280db7d1fac5b66fc6dad9f9662629e7365a55743daf9bdf73ebc4ea79" "/opt/rustwide/cargo-home/bin/cargo" "+4987e9d4227139400384ab59296ffee3b0fb1183" "metadata" "--no-deps" "--format-version=1", kill_on_drop: false }`
[INFO] [stdout] b8b9ab28a8734661693156c237a8c7931df4e39368719024174f29df20fd524f
[INFO] running `Command { std: "docker" "start" "-a" "b8b9ab28a8734661693156c237a8c7931df4e39368719024174f29df20fd524f", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "inspect" "b8b9ab28a8734661693156c237a8c7931df4e39368719024174f29df20fd524f", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "b8b9ab28a8734661693156c237a8c7931df4e39368719024174f29df20fd524f", kill_on_drop: false }`
[INFO] [stdout] b8b9ab28a8734661693156c237a8c7931df4e39368719024174f29df20fd524f
[INFO] running `Command { std: "docker" "create" "-v" "/var/lib/crater-agent-workspace/builds/worker-3-tc2/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-3-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:e90291280db7d1fac5b66fc6dad9f9662629e7365a55743daf9bdf73ebc4ea79" "/opt/rustwide/cargo-home/bin/cargo" "+4987e9d4227139400384ab59296ffee3b0fb1183" "build" "--frozen" "--message-format=json", kill_on_drop: false }`
[INFO] [stdout] 132ca0ba423815f1103957f78866d4e98fd78dbfe99a1d0afe06d0a3c4d691f8
[INFO] running `Command { std: "docker" "start" "-a" "132ca0ba423815f1103957f78866d4e98fd78dbfe99a1d0afe06d0a3c4d691f8", kill_on_drop: false }`
[INFO] [stderr] warning: no edition set: defaulting to the 2015 edition while the latest is 2024
[INFO] [stderr]    Compiling winapi-build v0.1.1
[INFO] [stderr]    Compiling winapi v0.2.8
[INFO] [stderr]    Compiling bitflags v0.4.0
[INFO] [stderr]    Compiling bytes v0.3.0
[INFO] [stderr]    Compiling slab v0.1.3
[INFO] [stderr]    Compiling void v1.0.2
[INFO] [stderr]    Compiling net2 v0.2.39
[INFO] [stderr]    Compiling quick-error v0.2.2
[INFO] [stderr]    Compiling nix v0.5.1
[INFO] [stderr]    Compiling ws2_32-sys v0.2.1
[INFO] [stderr]    Compiling kernel32-sys v0.2.2
[INFO] [stderr]    Compiling miow v0.1.5
[INFO] [stderr]    Compiling mio v0.5.1
[INFO] [stderr]    Compiling rotor v0.6.3
[INFO] [stderr]    Compiling rotor-tools v0.3.2 (/opt/rustwide/workdir)
[INFO] [stdout] warning: use of deprecated macro `try`: use the `?` operator instead
[INFO] [stdout]   --> src/loop_ext.rs:91:9
[INFO] [stdout]    |
[INFO] [stdout] 91 |         try!(self.add_machine_with(|scope| {
[INFO] [stdout]    |         ^^^
[INFO] [stdout]    |
[INFO] [stdout]    = note: `#[warn(deprecated)]` on by default
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: use of deprecated macro `try`: use the `?` operator instead
[INFO] [stdout]    --> src/loop_ext.rs:109:9
[INFO] [stdout]     |
[INFO] [stdout] 109 |         try!(self.add_machine_with(|scope| {
[INFO] [stdout]     |         ^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: trait objects without an explicit `dyn` are deprecated
[INFO] [stdout]   --> src/timer.rs:23:48
[INFO] [stdout]    |
[INFO] [stdout] 23 | pub type IntervalFunc<C> = Ticker<Interval<Box<FnMut(&mut Scope<C>) + Send>>>;
[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] 23 | pub type IntervalFunc<C> = Ticker<Interval<Box<dyn FnMut(&mut Scope<C>) + Send>>>;
[INFO] [stdout]    |                                                +++
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: trait objects without an explicit `dyn` are deprecated
[INFO] [stdout]    --> src/timer.rs:143:29
[INFO] [stdout]     |
[INFO] [stdout] 143 | impl<C> SimpleTimer for Box<FnMut(&mut Scope<C>) + Send> {
[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] 143 | impl<C> SimpleTimer for Box<dyn FnMut(&mut Scope<C>) + Send> {
[INFO] [stdout]     |                             +++
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused import: `GenericScope`
[INFO] [stdout]  --> src/timer.rs:3:49
[INFO] [stdout]   |
[INFO] [stdout] 3 | use rotor::{Machine, Scope, Response, EventSet, GenericScope, Time};
[INFO] [stdout]   |                                                 ^^^^^^^^^^^^
[INFO] [stdout]   |
[INFO] [stdout]   = note: `#[warn(unused_imports)]` (part of `#[warn(unused)]`) on by default
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused return value of `std::mem::replace` that must be used
[INFO] [stdout]   --> src/sync.rs:78:17
[INFO] [stdout]    |
[INFO] [stdout] 78 |                 mem::replace(&mut *guard, new_machine);
[INFO] [stdout]    |                 ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
[INFO] [stdout]    |
[INFO] [stdout]    = note: if you don't need the old value, you can just assign the new value directly
[INFO] [stdout]    = note: `#[warn(unused_must_use)]` (part of `#[warn(unused)]`) on by default
[INFO] [stdout] help: use `let _ = ...` to ignore the resulting value
[INFO] [stdout]    |
[INFO] [stdout] 78 |                 let _ = mem::replace(&mut *guard, new_machine);
[INFO] [stdout]    |                 +++++++
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused return value of `std::mem::replace` that must be used
[INFO] [stdout]   --> src/sync.rs:89:17
[INFO] [stdout]    |
[INFO] [stdout] 89 |                 mem::replace(&mut *guard, new_machine);
[INFO] [stdout]    |                 ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
[INFO] [stdout]    |
[INFO] [stdout]    = note: if you don't need the old value, you can just assign the new value directly
[INFO] [stdout] help: use `let _ = ...` to ignore the resulting value
[INFO] [stdout]    |
[INFO] [stdout] 89 |                 let _ = mem::replace(&mut *guard, new_machine);
[INFO] [stdout]    |                 +++++++
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stderr]     Finished `dev` profile [unoptimized + debuginfo] target(s) in 3.35s
[INFO] [stderr] warning: the following packages contain code that will be rejected by a future version of Rust: bitflags v0.4.0, rotor v0.6.3
[INFO] [stderr] note: to see what the problems were, use the option `--future-incompat-report`, or run `cargo report future-incompatibilities --id 2`
[INFO] running `Command { std: "docker" "inspect" "132ca0ba423815f1103957f78866d4e98fd78dbfe99a1d0afe06d0a3c4d691f8", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "132ca0ba423815f1103957f78866d4e98fd78dbfe99a1d0afe06d0a3c4d691f8", kill_on_drop: false }`
[INFO] [stdout] 132ca0ba423815f1103957f78866d4e98fd78dbfe99a1d0afe06d0a3c4d691f8
[INFO] running `Command { std: "docker" "create" "-v" "/var/lib/crater-agent-workspace/builds/worker-3-tc2/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-3-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:e90291280db7d1fac5b66fc6dad9f9662629e7365a55743daf9bdf73ebc4ea79" "/opt/rustwide/cargo-home/bin/cargo" "+4987e9d4227139400384ab59296ffee3b0fb1183" "test" "--frozen" "--no-run" "--message-format=json", kill_on_drop: false }`
[INFO] [stdout] 84f766ca1d855e29c68667d3dd60646eb10bd3bd664544d1c8fc26f8cc35ed7d
[INFO] running `Command { std: "docker" "start" "-a" "84f766ca1d855e29c68667d3dd60646eb10bd3bd664544d1c8fc26f8cc35ed7d", kill_on_drop: false }`
[INFO] [stderr] warning: no edition set: defaulting to the 2015 edition while the latest is 2024
[INFO] [stdout] warning: use of deprecated macro `try`: use the `?` operator instead
[INFO] [stdout]   --> src/loop_ext.rs:91:9
[INFO] [stdout]    |
[INFO] [stdout] 91 |         try!(self.add_machine_with(|scope| {
[INFO] [stdout]    |         ^^^
[INFO] [stdout]    |
[INFO] [stdout]    = note: `#[warn(deprecated)]` on by default
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: use of deprecated macro `try`: use the `?` operator instead
[INFO] [stdout]    --> src/loop_ext.rs:109:9
[INFO] [stdout]     |
[INFO] [stdout] 109 |         try!(self.add_machine_with(|scope| {
[INFO] [stdout]     |         ^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: trait objects without an explicit `dyn` are deprecated
[INFO] [stdout]   --> src/timer.rs:23:48
[INFO] [stdout]    |
[INFO] [stdout] 23 | pub type IntervalFunc<C> = Ticker<Interval<Box<FnMut(&mut Scope<C>) + Send>>>;
[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] 23 | pub type IntervalFunc<C> = Ticker<Interval<Box<dyn FnMut(&mut Scope<C>) + Send>>>;
[INFO] [stdout]    |                                                +++
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: trait objects without an explicit `dyn` are deprecated
[INFO] [stdout]    --> src/timer.rs:143:29
[INFO] [stdout]     |
[INFO] [stdout] 143 | impl<C> SimpleTimer for Box<FnMut(&mut Scope<C>) + Send> {
[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] 143 | impl<C> SimpleTimer for Box<dyn FnMut(&mut Scope<C>) + Send> {
[INFO] [stdout]     |                             +++
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused import: `GenericScope`
[INFO] [stdout]  --> src/timer.rs:3:49
[INFO] [stdout]   |
[INFO] [stdout] 3 | use rotor::{Machine, Scope, Response, EventSet, GenericScope, Time};
[INFO] [stdout]   |                                                 ^^^^^^^^^^^^
[INFO] [stdout]   |
[INFO] [stdout]   = note: `#[warn(unused_imports)]` (part of `#[warn(unused)]`) on by default
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused return value of `std::mem::replace` that must be used
[INFO] [stdout]   --> src/sync.rs:78:17
[INFO] [stdout]    |
[INFO] [stdout] 78 |                 mem::replace(&mut *guard, new_machine);
[INFO] [stdout]    |                 ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
[INFO] [stdout]    |
[INFO] [stdout]    = note: if you don't need the old value, you can just assign the new value directly
[INFO] [stdout]    = note: `#[warn(unused_must_use)]` (part of `#[warn(unused)]`) on by default
[INFO] [stdout] help: use `let _ = ...` to ignore the resulting value
[INFO] [stdout]    |
[INFO] [stdout] 78 |                 let _ = mem::replace(&mut *guard, new_machine);
[INFO] [stdout]    |                 +++++++
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused return value of `std::mem::replace` that must be used
[INFO] [stdout]   --> src/sync.rs:89:17
[INFO] [stdout]    |
[INFO] [stdout] 89 |                 mem::replace(&mut *guard, new_machine);
[INFO] [stdout]    |                 ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
[INFO] [stdout]    |
[INFO] [stdout]    = note: if you don't need the old value, you can just assign the new value directly
[INFO] [stdout] help: use `let _ = ...` to ignore the resulting value
[INFO] [stdout]    |
[INFO] [stdout] 89 |                 let _ = mem::replace(&mut *guard, new_machine);
[INFO] [stdout]    |                 +++++++
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stderr]    Compiling rotor-tools v0.3.2 (/opt/rustwide/workdir)
[INFO] [stdout] warning: use of deprecated macro `try`: use the `?` operator instead
[INFO] [stdout]   --> src/loop_ext.rs:91:9
[INFO] [stdout]    |
[INFO] [stdout] 91 |         try!(self.add_machine_with(|scope| {
[INFO] [stdout]    |         ^^^
[INFO] [stdout]    |
[INFO] [stdout]    = note: `#[warn(deprecated)]` on by default
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: use of deprecated macro `try`: use the `?` operator instead
[INFO] [stdout]    --> src/loop_ext.rs:109:9
[INFO] [stdout]     |
[INFO] [stdout] 109 |         try!(self.add_machine_with(|scope| {
[INFO] [stdout]     |         ^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: trait objects without an explicit `dyn` are deprecated
[INFO] [stdout]   --> src/timer.rs:23:48
[INFO] [stdout]    |
[INFO] [stdout] 23 | pub type IntervalFunc<C> = Ticker<Interval<Box<FnMut(&mut Scope<C>) + Send>>>;
[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] 23 | pub type IntervalFunc<C> = Ticker<Interval<Box<dyn FnMut(&mut Scope<C>) + Send>>>;
[INFO] [stdout]    |                                                +++
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: trait objects without an explicit `dyn` are deprecated
[INFO] [stdout]    --> src/timer.rs:143:29
[INFO] [stdout]     |
[INFO] [stdout] 143 | impl<C> SimpleTimer for Box<FnMut(&mut Scope<C>) + Send> {
[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] 143 | impl<C> SimpleTimer for Box<dyn FnMut(&mut Scope<C>) + Send> {
[INFO] [stdout]     |                             +++
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused import: `GenericScope`
[INFO] [stdout]  --> src/timer.rs:3:49
[INFO] [stdout]   |
[INFO] [stdout] 3 | use rotor::{Machine, Scope, Response, EventSet, GenericScope, Time};
[INFO] [stdout]   |                                                 ^^^^^^^^^^^^
[INFO] [stdout]   |
[INFO] [stdout]   = note: `#[warn(unused_imports)]` (part of `#[warn(unused)]`) on by default
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused return value of `std::mem::replace` that must be used
[INFO] [stdout]   --> src/sync.rs:78:17
[INFO] [stdout]    |
[INFO] [stdout] 78 |                 mem::replace(&mut *guard, new_machine);
[INFO] [stdout]    |                 ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
[INFO] [stdout]    |
[INFO] [stdout]    = note: if you don't need the old value, you can just assign the new value directly
[INFO] [stdout]    = note: `#[warn(unused_must_use)]` (part of `#[warn(unused)]`) on by default
[INFO] [stdout] help: use `let _ = ...` to ignore the resulting value
[INFO] [stdout]    |
[INFO] [stdout] 78 |                 let _ = mem::replace(&mut *guard, new_machine);
[INFO] [stdout]    |                 +++++++
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused return value of `std::mem::replace` that must be used
[INFO] [stdout]   --> src/sync.rs:89:17
[INFO] [stdout]    |
[INFO] [stdout] 89 |                 mem::replace(&mut *guard, new_machine);
[INFO] [stdout]    |                 ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
[INFO] [stdout]    |
[INFO] [stdout]    = note: if you don't need the old value, you can just assign the new value directly
[INFO] [stdout] help: use `let _ = ...` to ignore the resulting value
[INFO] [stdout]    |
[INFO] [stdout] 89 |                 let _ = mem::replace(&mut *guard, new_machine);
[INFO] [stdout]    |                 +++++++
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stderr]     Finished `test` profile [unoptimized + debuginfo] target(s) in 0.97s
[INFO] [stderr] warning: the following packages contain code that will be rejected by a future version of Rust: bitflags v0.4.0, rotor v0.6.3
[INFO] [stderr] note: to see what the problems were, use the option `--future-incompat-report`, or run `cargo report future-incompatibilities --id 2`
[INFO] running `Command { std: "docker" "inspect" "84f766ca1d855e29c68667d3dd60646eb10bd3bd664544d1c8fc26f8cc35ed7d", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "84f766ca1d855e29c68667d3dd60646eb10bd3bd664544d1c8fc26f8cc35ed7d", kill_on_drop: false }`
[INFO] [stdout] 84f766ca1d855e29c68667d3dd60646eb10bd3bd664544d1c8fc26f8cc35ed7d
