[INFO] cloning repository https://github.com/lochbrunner/rust-hacks
[INFO] running `Command { std: "git" "-c" "credential.helper=" "-c" "credential.helper=/workspace/cargo-home/bin/git-credential-null" "clone" "--bare" "https://github.com/lochbrunner/rust-hacks" "/workspace/cache/git-repos/https%3A%2F%2Fgithub.com%2Flochbrunner%2Frust-hacks", kill_on_drop: false }`
[INFO] [stderr] Cloning into bare repository '/workspace/cache/git-repos/https%3A%2F%2Fgithub.com%2Flochbrunner%2Frust-hacks'...
[INFO] running `Command { std: "git" "rev-parse" "HEAD", kill_on_drop: false }`
[INFO] [stdout] 04a14e80469215a2b365dd3d60ca86a6520cd2ad
[INFO] testing lochbrunner/rust-hacks against 1.60.0 for beta-1.61-1
[INFO] running `Command { std: "git" "clone" "/workspace/cache/git-repos/https%3A%2F%2Fgithub.com%2Flochbrunner%2Frust-hacks" "/workspace/builds/worker-43/source", kill_on_drop: false }`
[INFO] [stderr] Cloning into '/workspace/builds/worker-43/source'...
[INFO] [stderr] done.
[INFO] validating manifest of git repo https://github.com/lochbrunner/rust-hacks on toolchain 1.60.0
[INFO] running `Command { std: "/workspace/cargo-home/bin/cargo" "+1.60.0" "metadata" "--manifest-path" "Cargo.toml" "--no-deps", kill_on_drop: false }`
[INFO] started tweaking git repo https://github.com/lochbrunner/rust-hacks
[INFO] finished tweaking git repo https://github.com/lochbrunner/rust-hacks
[INFO] tweaked toml for git repo https://github.com/lochbrunner/rust-hacks written to /workspace/builds/worker-43/source/Cargo.toml
[INFO] crate git repo https://github.com/lochbrunner/rust-hacks already has a lockfile, it will not be regenerated
[INFO] running `Command { std: "/workspace/cargo-home/bin/cargo" "+1.60.0" "fetch" "--manifest-path" "Cargo.toml", kill_on_drop: false }`
[INFO] [stderr]     Blocking waiting for file lock on package cache
[INFO] [stderr]     Blocking waiting for file lock on package cache
[INFO] running `Command { std: "docker" "create" "-v" "/var/lib/crater-agent-workspace/builds/worker-43/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-43/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:b0c94ce3c1162fcb8e57cac5b65ec2f72eabb1eebea4fcc35e269e823f681646" "/opt/rustwide/cargo-home/bin/cargo" "+1.60.0" "metadata" "--no-deps" "--format-version=1", kill_on_drop: false }`
[INFO] [stdout] 2e3479905b2797d30a6e42844eb51bf43fdb40e34405f7e1b11f9cc9816fb5a9
[INFO] running `Command { std: "docker" "start" "-a" "2e3479905b2797d30a6e42844eb51bf43fdb40e34405f7e1b11f9cc9816fb5a9", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "inspect" "2e3479905b2797d30a6e42844eb51bf43fdb40e34405f7e1b11f9cc9816fb5a9", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "2e3479905b2797d30a6e42844eb51bf43fdb40e34405f7e1b11f9cc9816fb5a9", kill_on_drop: false }`
[INFO] [stdout] 2e3479905b2797d30a6e42844eb51bf43fdb40e34405f7e1b11f9cc9816fb5a9
[INFO] running `Command { std: "docker" "create" "-v" "/var/lib/crater-agent-workspace/builds/worker-43/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-43/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:b0c94ce3c1162fcb8e57cac5b65ec2f72eabb1eebea4fcc35e269e823f681646" "/opt/rustwide/cargo-home/bin/cargo" "+1.60.0" "build" "--frozen" "--message-format=json", kill_on_drop: false }`
[INFO] [stdout] 221591adcb7fdba03edf2000e37336019c4c114f5f44460f3f99dd240f17cadc
[INFO] running `Command { std: "docker" "start" "-a" "221591adcb7fdba03edf2000e37336019c4c114f5f44460f3f99dd240f17cadc", kill_on_drop: false }`
[INFO] [stderr]    Compiling rust-hacks v0.1.0 (/opt/rustwide/workdir)
[INFO] [stdout] warning: unused imports: `Filter`, `Map`
[INFO] [stdout]  --> src/sample_map.rs:1:17
[INFO] [stdout]   |
[INFO] [stdout] 1 | use std::iter::{Filter, Iterator, Map};
[INFO] [stdout]   |                 ^^^^^^            ^^^
[INFO] [stdout]   |
[INFO] [stdout]   = note: `#[warn(unused_imports)]` on by default
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: trait objects without an explicit `dyn` are deprecated
[INFO] [stdout]   --> src/sample_map.rs:16:13
[INFO] [stdout]    |
[INFO] [stdout] 16 | type P<S> = FnMut() -> S;
[INFO] [stdout]    |             ^^^^^^^^^^^^
[INFO] [stdout]    |
[INFO] [stdout]    = note: `#[warn(bare_trait_objects)]` on by default
[INFO] [stdout]    = warning: this is accepted in the current edition (Rust 2018) but is a hard error in Rust 2021!
[INFO] [stdout]    = note: for more information, see <https://doc.rust-lang.org/nightly/edition-guide/rust-2021/warnings-promoted-to-error.html>
[INFO] [stdout] help: use `dyn`
[INFO] [stdout]    |
[INFO] [stdout] 16 - type P<S> = FnMut() -> S;
[INFO] [stdout] 16 + type P<S> = dyn FnMut() -> S;
[INFO] [stdout]    | 
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `s`
[INFO] [stdout]   --> src/sample_map.rs:27:13
[INFO] [stdout]    |
[INFO] [stdout] 27 |         let s = self.s.iter().nth(0).unwrap();
[INFO] [stdout]    |             ^ help: if this is intentional, prefix it with an underscore: `_s`
[INFO] [stdout]    |
[INFO] [stdout]    = note: `#[warn(unused_variables)]` on by default
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: associated function is never used: `new`
[INFO] [stdout]   --> src/cross_join.rs:23:12
[INFO] [stdout]    |
[INFO] [stdout] 23 |     pub fn new(left_iter: L, samples: &'a [R]) -> CrossJoin<'a, R, L> {
[INFO] [stdout]    |            ^^^
[INFO] [stdout]    |
[INFO] [stdout]    = note: `#[warn(dead_code)]` on by default
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: associated function is never used: `new`
[INFO] [stdout]   --> src/sample_map.rs:11:19
[INFO] [stdout]    |
[INFO] [stdout] 11 |     pub(super) fn new(iter: I, f: F, s: &'a [S]) -> SampleMap<'a, I, F, S> {
[INFO] [stdout]    |                   ^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: type alias is never used: `P`
[INFO] [stdout]   --> src/sample_map.rs:16:1
[INFO] [stdout]    |
[INFO] [stdout] 16 | type P<S> = FnMut() -> S;
[INFO] [stdout]    | ^^^^^^^^^^^^^^^^^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: 6 warnings emitted
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stderr]     Finished dev [unoptimized + debuginfo] target(s) in 13.36s
[INFO] running `Command { std: "docker" "inspect" "221591adcb7fdba03edf2000e37336019c4c114f5f44460f3f99dd240f17cadc", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "221591adcb7fdba03edf2000e37336019c4c114f5f44460f3f99dd240f17cadc", kill_on_drop: false }`
[INFO] [stdout] 221591adcb7fdba03edf2000e37336019c4c114f5f44460f3f99dd240f17cadc
[INFO] running `Command { std: "docker" "create" "-v" "/var/lib/crater-agent-workspace/builds/worker-43/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-43/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:b0c94ce3c1162fcb8e57cac5b65ec2f72eabb1eebea4fcc35e269e823f681646" "/opt/rustwide/cargo-home/bin/cargo" "+1.60.0" "test" "--frozen" "--no-run" "--message-format=json", kill_on_drop: false }`
[INFO] [stdout] 9de12fcbd0dc9b918f1362681ff56d2e4d17a3a756affea9859a9a68f54cdcd4
[INFO] running `Command { std: "docker" "start" "-a" "9de12fcbd0dc9b918f1362681ff56d2e4d17a3a756affea9859a9a68f54cdcd4", kill_on_drop: false }`
[INFO] [stderr]     Blocking waiting for file lock on package cache
[INFO] [stderr]    Compiling rust-hacks v0.1.0 (/opt/rustwide/workdir)
[INFO] [stdout] warning: unused imports: `Filter`, `Map`
[INFO] [stdout]  --> src/sample_map.rs:1:17
[INFO] [stdout]   |
[INFO] [stdout] 1 | use std::iter::{Filter, Iterator, Map};
[INFO] [stdout]   |                 ^^^^^^            ^^^
[INFO] [stdout]   |
[INFO] [stdout]   = note: `#[warn(unused_imports)]` on by default
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: trait objects without an explicit `dyn` are deprecated
[INFO] [stdout]   --> src/sample_map.rs:16:13
[INFO] [stdout]    |
[INFO] [stdout] 16 | type P<S> = FnMut() -> S;
[INFO] [stdout]    |             ^^^^^^^^^^^^
[INFO] [stdout]    |
[INFO] [stdout]    = note: `#[warn(bare_trait_objects)]` on by default
[INFO] [stdout]    = warning: this is accepted in the current edition (Rust 2018) but is a hard error in Rust 2021!
[INFO] [stdout]    = note: for more information, see <https://doc.rust-lang.org/nightly/edition-guide/rust-2021/warnings-promoted-to-error.html>
[INFO] [stdout] help: use `dyn`
[INFO] [stdout]    |
[INFO] [stdout] 16 - type P<S> = FnMut() -> S;
[INFO] [stdout] 16 + type P<S> = dyn FnMut() -> S;
[INFO] [stdout]    | 
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: trait objects without an explicit `dyn` are deprecated
[INFO] [stdout]   --> src/count_calls.rs:21:18
[INFO] [stdout]    |
[INFO] [stdout] 21 |     fn f(p: &mut FnMut() -> i32) {
[INFO] [stdout]    |                  ^^^^^^^^^^^^^^
[INFO] [stdout]    |
[INFO] [stdout]    = warning: this is accepted in the current edition (Rust 2018) but is a hard error in Rust 2021!
[INFO] [stdout]    = note: for more information, see <https://doc.rust-lang.org/nightly/edition-guide/rust-2021/warnings-promoted-to-error.html>
[INFO] [stdout] help: use `dyn`
[INFO] [stdout]    |
[INFO] [stdout] 21 -     fn f(p: &mut FnMut() -> i32) {
[INFO] [stdout] 21 +     fn f(p: &mut dyn FnMut() -> i32) {
[INFO] [stdout]    | 
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `s`
[INFO] [stdout]   --> src/sample_map.rs:27:13
[INFO] [stdout]    |
[INFO] [stdout] 27 |         let s = self.s.iter().nth(0).unwrap();
[INFO] [stdout]    |             ^ help: if this is intentional, prefix it with an underscore: `_s`
[INFO] [stdout]    |
[INFO] [stdout]    = note: `#[warn(unused_variables)]` on by default
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `arg`
[INFO] [stdout]  --> src/move_in_map.rs:6:12
[INFO] [stdout]   |
[INFO] [stdout] 6 |     fn foo(arg: A) -> i32 {
[INFO] [stdout]   |            ^^^ help: if this is intentional, prefix it with an underscore: `_arg`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused variable: `output`
[INFO] [stdout]   --> src/move_in_map.rs:13:13
[INFO] [stdout]    |
[INFO] [stdout] 13 |         let output = inputs.into_iter().map(|item| foo(item));
[INFO] [stdout]    |             ^^^^^^ help: if this is intentional, prefix it with an underscore: `_output`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: type alias is never used: `P`
[INFO] [stdout]   --> src/sample_map.rs:16:1
[INFO] [stdout]    |
[INFO] [stdout] 16 | type P<S> = FnMut() -> S;
[INFO] [stdout]    | ^^^^^^^^^^^^^^^^^^^^^^^^^
[INFO] [stdout]    |
[INFO] [stdout]    = note: `#[warn(dead_code)]` on by default
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused `Map` that must be used
[INFO] [stdout]    --> src/cross_join.rs:120:9
[INFO] [stdout]     |
[INFO] [stdout] 120 |         input.iter().map(|s| s);
[INFO] [stdout]     |         ^^^^^^^^^^^^^^^^^^^^^^^^
[INFO] [stdout]     |
[INFO] [stdout]     = note: `#[warn(unused_must_use)]` on by default
[INFO] [stdout]     = note: iterators are lazy and do nothing unless consumed
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: 8 warnings emitted
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stderr]     Finished test [unoptimized + debuginfo] target(s) in 3.26s
[INFO] running `Command { std: "docker" "inspect" "9de12fcbd0dc9b918f1362681ff56d2e4d17a3a756affea9859a9a68f54cdcd4", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "9de12fcbd0dc9b918f1362681ff56d2e4d17a3a756affea9859a9a68f54cdcd4", kill_on_drop: false }`
[INFO] [stdout] 9de12fcbd0dc9b918f1362681ff56d2e4d17a3a756affea9859a9a68f54cdcd4
[INFO] running `Command { std: "docker" "create" "-v" "/var/lib/crater-agent-workspace/builds/worker-43/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-43/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:b0c94ce3c1162fcb8e57cac5b65ec2f72eabb1eebea4fcc35e269e823f681646" "/opt/rustwide/cargo-home/bin/cargo" "+1.60.0" "test" "--frozen", kill_on_drop: false }`
[INFO] [stdout] 72885bd1cedd40805cb1931532060586bd49da2dcc98860a7b327adfd00e21b3
[INFO] running `Command { std: "docker" "start" "-a" "72885bd1cedd40805cb1931532060586bd49da2dcc98860a7b327adfd00e21b3", kill_on_drop: false }`
[INFO] [stderr]     Blocking waiting for file lock on package cache
[INFO] [stderr] warning: unused imports: `Filter`, `Map`
[INFO] [stdout] 
[INFO] [stderr]  --> src/sample_map.rs:1:17
[INFO] [stdout] running 7 tests
[INFO] [stderr]   |
[INFO] [stdout] test count_calls::stackoverflow::test ... ok
[INFO] [stderr] 1 | use std::iter::{Filter, Iterator, Map};
[INFO] [stdout] test learn_iter::specs_learn::sam_trait ... ok
[INFO] [stderr]   |                 ^^^^^^            ^^^
[INFO] [stdout] test cross_join::specs::cross_iter ... ok
[INFO] [stderr]   |
[INFO] [stdout] test learn_iter::specs_learn::sam_trait_filter ... ok
[INFO] [stderr]   = note: `#[warn(unused_imports)]` on by default
[INFO] [stdout] test learn_iter::specs_learn::sam_trait_map ... ok
[INFO] [stderr] 
[INFO] [stdout] test move_in_map::specs::move_in_maps ... ok
[INFO] [stderr] warning: trait objects without an explicit `dyn` are deprecated
[INFO] [stdout] test sample_map::specs::sample_map_simple ... ok
[INFO] [stderr]   --> src/sample_map.rs:16:13
[INFO] [stdout] 
[INFO] [stderr]    |
[INFO] [stdout] test result: ok. 7 passed; 0 failed; 0 ignored; 0 measured; 0 filtered out; finished in 0.00s
[INFO] [stderr] 16 | type P<S> = FnMut() -> S;
[INFO] [stdout] 
[INFO] [stderr]    |             ^^^^^^^^^^^^
[INFO] [stderr]    |
[INFO] [stderr]    = note: `#[warn(bare_trait_objects)]` on by default
[INFO] [stderr]    = warning: this is accepted in the current edition (Rust 2018) but is a hard error in Rust 2021!
[INFO] [stderr]    = note: for more information, see <https://doc.rust-lang.org/nightly/edition-guide/rust-2021/warnings-promoted-to-error.html>
[INFO] [stderr] help: use `dyn`
[INFO] [stderr]    |
[INFO] [stderr] 16 - type P<S> = FnMut() -> S;
[INFO] [stderr] 16 + type P<S> = dyn FnMut() -> S;
[INFO] [stderr]    | 
[INFO] [stderr] 
[INFO] [stderr] warning: trait objects without an explicit `dyn` are deprecated
[INFO] [stderr]   --> src/count_calls.rs:21:18
[INFO] [stderr]    |
[INFO] [stderr] 21 |     fn f(p: &mut FnMut() -> i32) {
[INFO] [stderr]    |                  ^^^^^^^^^^^^^^
[INFO] [stderr]    |
[INFO] [stderr]    = warning: this is accepted in the current edition (Rust 2018) but is a hard error in Rust 2021!
[INFO] [stderr]    = note: for more information, see <https://doc.rust-lang.org/nightly/edition-guide/rust-2021/warnings-promoted-to-error.html>
[INFO] [stderr] help: use `dyn`
[INFO] [stderr]    |
[INFO] [stderr] 21 -     fn f(p: &mut FnMut() -> i32) {
[INFO] [stderr] 21 +     fn f(p: &mut dyn FnMut() -> i32) {
[INFO] [stderr]    | 
[INFO] [stderr] 
[INFO] [stderr] warning: unused variable: `s`
[INFO] [stderr]   --> src/sample_map.rs:27:13
[INFO] [stderr]    |
[INFO] [stderr] 27 |         let s = self.s.iter().nth(0).unwrap();
[INFO] [stderr]    |             ^ help: if this is intentional, prefix it with an underscore: `_s`
[INFO] [stderr]    |
[INFO] [stderr]    = note: `#[warn(unused_variables)]` on by default
[INFO] [stderr] 
[INFO] [stderr] warning: unused variable: `arg`
[INFO] [stderr]  --> src/move_in_map.rs:6:12
[INFO] [stderr]   |
[INFO] [stderr] 6 |     fn foo(arg: A) -> i32 {
[INFO] [stderr]   |            ^^^ help: if this is intentional, prefix it with an underscore: `_arg`
[INFO] [stderr] 
[INFO] [stderr] warning: unused variable: `output`
[INFO] [stderr]   --> src/move_in_map.rs:13:13
[INFO] [stderr]    |
[INFO] [stderr] 13 |         let output = inputs.into_iter().map(|item| foo(item));
[INFO] [stderr]    |             ^^^^^^ help: if this is intentional, prefix it with an underscore: `_output`
[INFO] [stderr] 
[INFO] [stderr] warning: type alias is never used: `P`
[INFO] [stderr]   --> src/sample_map.rs:16:1
[INFO] [stderr]    |
[INFO] [stderr] 16 | type P<S> = FnMut() -> S;
[INFO] [stderr]    | ^^^^^^^^^^^^^^^^^^^^^^^^^
[INFO] [stderr]    |
[INFO] [stderr]    = note: `#[warn(dead_code)]` on by default
[INFO] [stderr] 
[INFO] [stderr] warning: unused `Map` that must be used
[INFO] [stderr]    --> src/cross_join.rs:120:9
[INFO] [stderr]     |
[INFO] [stderr] 120 |         input.iter().map(|s| s);
[INFO] [stderr]     |         ^^^^^^^^^^^^^^^^^^^^^^^^
[INFO] [stderr]     |
[INFO] [stderr]     = note: `#[warn(unused_must_use)]` on by default
[INFO] [stderr]     = note: iterators are lazy and do nothing unless consumed
[INFO] [stderr] 
[INFO] [stderr] warning: `rust-hacks` (bin "rust-hacks" test) generated 8 warnings
[INFO] [stderr]     Finished test [unoptimized + debuginfo] target(s) in 0.89s
[INFO] [stderr]      Running unittests (/opt/rustwide/target/debug/deps/rust_hacks-1a463a467a06e39f)
[INFO] running `Command { std: "docker" "inspect" "72885bd1cedd40805cb1931532060586bd49da2dcc98860a7b327adfd00e21b3", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "72885bd1cedd40805cb1931532060586bd49da2dcc98860a7b327adfd00e21b3", kill_on_drop: false }`
[INFO] [stdout] 72885bd1cedd40805cb1931532060586bd49da2dcc98860a7b327adfd00e21b3