[INFO] fetching crate scholar 0.1.7...
[INFO] testing scholar-0.1.7 against beta-2020-10-09 for beta-1.48-1
[INFO] extracting crate scholar 0.1.7 into /workspace/builds/worker-8/source
[INFO] validating manifest of crates.io crate scholar 0.1.7 on toolchain beta-2020-10-09
[INFO] running `Command { std: "/workspace/cargo-home/bin/cargo" "+beta-2020-10-09" "read-manifest" "--manifest-path" "Cargo.toml", kill_on_drop: false }`
[INFO] started tweaking crates.io crate scholar 0.1.7
[INFO] finished tweaking crates.io crate scholar 0.1.7
[INFO] tweaked toml for crates.io crate scholar 0.1.7 written to /workspace/builds/worker-8/source/Cargo.toml
[INFO] crate crates.io crate scholar 0.1.7 already has a lockfile, it will not be regenerated
[INFO] running `Command { std: "/workspace/cargo-home/bin/cargo" "+beta-2020-10-09" "fetch" "--locked" "--manifest-path" "Cargo.toml", kill_on_drop: false }`
[INFO] [stderr]  Downloading crates ...
[INFO] [stderr]   Downloaded simba v0.1.2
[INFO] [stderr]   Downloaded thiserror-impl v1.0.15
[INFO] [stderr]   Downloaded thiserror v1.0.15
[INFO] [stderr]   Downloaded nalgebra v0.21.0
[INFO] running `Command { std: "docker" "create" "-v" "/var/lib/crater-agent-workspace/builds/worker-8/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-8/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" "rustops/crates-build-env@sha256:d92eaeed33fa75130ca1ee6c8a01d1ffb62bac859dfdfb3450e3e5d1c0146529" "/opt/rustwide/cargo-home/bin/cargo" "+beta-2020-10-09" "metadata" "--no-deps" "--format-version=1", kill_on_drop: false }`
[INFO] [stderr] WARNING: Your kernel does not support swap limit capabilities or the cgroup is not mounted. Memory limited without swap.
[INFO] [stdout] 62eb01f18ac398c3a1371f337b97cbfceb1c535738cf638220a8750fc65ae369
[INFO] running `Command { std: "docker" "start" "-a" "62eb01f18ac398c3a1371f337b97cbfceb1c535738cf638220a8750fc65ae369", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "inspect" "62eb01f18ac398c3a1371f337b97cbfceb1c535738cf638220a8750fc65ae369", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "62eb01f18ac398c3a1371f337b97cbfceb1c535738cf638220a8750fc65ae369", kill_on_drop: false }`
[INFO] [stdout] 62eb01f18ac398c3a1371f337b97cbfceb1c535738cf638220a8750fc65ae369
[INFO] running `Command { std: "docker" "create" "-v" "/var/lib/crater-agent-workspace/builds/worker-8/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-8/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" "rustops/crates-build-env@sha256:d92eaeed33fa75130ca1ee6c8a01d1ffb62bac859dfdfb3450e3e5d1c0146529" "/opt/rustwide/cargo-home/bin/cargo" "+beta-2020-10-09" "build" "--frozen" "--message-format=json", kill_on_drop: false }`
[INFO] [stdout] 5752e1bb7dfdbc6aec45d30958afb8b1edb87460c1d2ce853df02d8c3369c175
[INFO] [stderr] WARNING: Your kernel does not support swap limit capabilities or the cgroup is not mounted. Memory limited without swap.
[INFO] running `Command { std: "docker" "start" "-a" "5752e1bb7dfdbc6aec45d30958afb8b1edb87460c1d2ce853df02d8c3369c175", kill_on_drop: false }`
[INFO] [stderr]     Blocking waiting for file lock on package cache
[INFO] [stderr]    Compiling proc-macro2 v1.0.10
[INFO] [stderr]    Compiling syn v1.0.17
[INFO] [stderr]    Compiling serde v1.0.106
[INFO] [stderr]    Compiling ryu v1.0.3
[INFO] [stderr]    Compiling regex-syntax v0.6.17
[INFO] [stderr]    Compiling number_prefix v0.3.0
[INFO] [stderr]    Compiling num-traits v0.2.11
[INFO] [stderr]    Compiling num-complex v0.2.4
[INFO] [stderr]    Compiling num-rational v0.2.4
[INFO] [stderr]    Compiling regex-automata v0.1.9
[INFO] [stderr]    Compiling termios v0.3.2
[INFO] [stderr]    Compiling clicolors-control v1.0.1
[INFO] [stderr]    Compiling generic-array v0.13.2
[INFO] [stderr]    Compiling rand_distr v0.2.2
[INFO] [stderr]    Compiling quote v1.0.3
[INFO] [stderr]    Compiling num-integer v0.1.42
[INFO] [stderr]    Compiling approx v0.3.2
[INFO] [stderr]    Compiling regex v1.3.6
[INFO] [stderr]    Compiling console v0.10.0
[INFO] [stderr]    Compiling indicatif v0.14.0
[INFO] [stderr]    Compiling serde_derive v1.0.106
[INFO] [stderr]    Compiling paste-impl v0.1.10
[INFO] [stderr]    Compiling thiserror-impl v1.0.15
[INFO] [stderr]    Compiling paste v0.1.10
[INFO] [stderr]    Compiling thiserror v1.0.15
[INFO] [stderr]    Compiling bstr v0.2.12
[INFO] [stderr]    Compiling bincode v1.2.1
[INFO] [stderr]    Compiling simba v0.1.2
[INFO] [stderr]    Compiling csv v1.1.3
[INFO] [stderr]    Compiling nalgebra v0.21.0
[INFO] [stderr]    Compiling scholar v0.1.7 (/opt/rustwide/workdir)
[INFO] [stderr]     Finished dev [unoptimized + debuginfo] target(s) in 1m 42s
[INFO] running `Command { std: "docker" "inspect" "5752e1bb7dfdbc6aec45d30958afb8b1edb87460c1d2ce853df02d8c3369c175", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "5752e1bb7dfdbc6aec45d30958afb8b1edb87460c1d2ce853df02d8c3369c175", kill_on_drop: false }`
[INFO] [stdout] 5752e1bb7dfdbc6aec45d30958afb8b1edb87460c1d2ce853df02d8c3369c175
[INFO] running `Command { std: "docker" "create" "-v" "/var/lib/crater-agent-workspace/builds/worker-8/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-8/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" "rustops/crates-build-env@sha256:d92eaeed33fa75130ca1ee6c8a01d1ffb62bac859dfdfb3450e3e5d1c0146529" "/opt/rustwide/cargo-home/bin/cargo" "+beta-2020-10-09" "test" "--frozen" "--no-run" "--message-format=json", kill_on_drop: false }`
[INFO] [stdout] f4ac52e00e07784be6d8d5e0e04c98cc51072f893c40d57a5aa0785314688251
[INFO] [stderr] WARNING: Your kernel does not support swap limit capabilities or the cgroup is not mounted. Memory limited without swap.
[INFO] running `Command { std: "docker" "start" "-a" "f4ac52e00e07784be6d8d5e0e04c98cc51072f893c40d57a5aa0785314688251", kill_on_drop: false }`
[INFO] [stderr]     Blocking waiting for file lock on package cache
[INFO] [stderr]    Compiling anyhow v1.0.28
[INFO] [stderr]    Compiling scholar v0.1.7 (/opt/rustwide/workdir)
[INFO] [stderr]     Finished test [unoptimized + debuginfo] target(s) in 3.57s
[INFO] running `Command { std: "docker" "inspect" "f4ac52e00e07784be6d8d5e0e04c98cc51072f893c40d57a5aa0785314688251", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "f4ac52e00e07784be6d8d5e0e04c98cc51072f893c40d57a5aa0785314688251", kill_on_drop: false }`
[INFO] [stdout] f4ac52e00e07784be6d8d5e0e04c98cc51072f893c40d57a5aa0785314688251
[INFO] running `Command { std: "docker" "create" "-v" "/var/lib/crater-agent-workspace/builds/worker-8/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-8/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" "rustops/crates-build-env@sha256:d92eaeed33fa75130ca1ee6c8a01d1ffb62bac859dfdfb3450e3e5d1c0146529" "/opt/rustwide/cargo-home/bin/cargo" "+beta-2020-10-09" "test" "--frozen", kill_on_drop: false }`
[INFO] [stdout] 143dbe0b133cbb984a994ca93ffd823c7941be8873be316bc8770733018e604f
[INFO] [stderr] WARNING: Your kernel does not support swap limit capabilities or the cgroup is not mounted. Memory limited without swap.
[INFO] running `Command { std: "docker" "start" "-a" "143dbe0b133cbb984a994ca93ffd823c7941be8873be316bc8770733018e604f", kill_on_drop: false }`
[INFO] [stderr]     Finished test [unoptimized + debuginfo] target(s) in 0.15s
[INFO] [stdout] 
[INFO] [stderr]      Running /opt/rustwide/target/debug/deps/scholar-4f0b0d95d4b6c09e
[INFO] [stdout] running 0 tests
[INFO] [stdout] 
[INFO] [stdout] test result: ok. 0 passed; 0 failed; 0 ignored; 0 measured; 0 filtered out
[INFO] [stdout] 
[INFO] [stderr]    Doc-tests scholar
[INFO] [stdout] 
[INFO] [stdout] running 14 tests
[INFO] [stdout] test src/network.rs - network::Activation::derivative (line 304) ... FAILED
[INFO] [stdout] test src/network.rs - network::NeuralNet<A>::test (line 130) ... FAILED
[INFO] [stdout] test src/network.rs - network::Activation::derivative (line 310) ... FAILED
[INFO] [stdout] test src/network.rs - network::NeuralNet<A>::save (line 164) ... FAILED
[INFO] [stdout] test src/network.rs - network::Activation::derivative (line 295) ... FAILED
[INFO] [stdout] test src/network.rs - network::NeuralNet<A>::train (line 88) ... FAILED
[INFO] [stdout] test src/dataset.rs - dataset::Dataset::split (line 82) ... FAILED
[INFO] [stdout] test src/network.rs - network::NeuralNet<A>::from_file (line 72) ... FAILED
[INFO] [stdout] test src/network.rs - network::Activation (line 264) ... ok
[INFO] [stdout] test src/dataset.rs - dataset::Dataset::rows (line 119) ... ok
[INFO] [stdout] test src/dataset.rs - dataset::Dataset (line 10) ... ok
[INFO] [stdout] test src/dataset.rs - dataset::Dataset::from_csv (line 38) ... ok
[INFO] [stdout] test src/network.rs - network::NeuralNet<A>::new (line 27) ... ok
[INFO] [stdout] test src/network.rs - network::NeuralNet<A>::guess (line 185) ... ok
[INFO] [stdout] 
[INFO] [stdout] failures:
[INFO] [stdout] 
[INFO] [stdout] ---- src/network.rs - network::Activation::derivative (line 304) stdout ----
[INFO] [stdout] error[E0425]: cannot find value `x` in this scope
[INFO] [stdout]  --> src/network.rs:305:1
[INFO] [stdout]   |
[INFO] [stdout] 3 | x * (1 - x)
[INFO] [stdout]   | ^ not found in this scope
[INFO] [stdout] 
[INFO] [stdout] error[E0425]: cannot find value `x` in this scope
[INFO] [stdout]  --> src/network.rs:305:10
[INFO] [stdout]   |
[INFO] [stdout] 3 | x * (1 - x)
[INFO] [stdout]   |          ^ not found in this scope
[INFO] [stdout] 
[INFO] [stdout] error: aborting due to 2 previous errors
[INFO] [stdout] 
[INFO] [stdout] For more information about this error, try `rustc --explain E0425`.
[INFO] [stdout] Couldn't compile the test.
[INFO] [stdout] ---- src/network.rs - network::NeuralNet<A>::test (line 130) stdout ----
[INFO] [stdout] error[E0277]: the `?` operator can only be used in a function that returns `Result` or `Option` (or another type that implements `Try`)
[INFO] [stdout]   --> src/network.rs:133:15
[INFO] [stdout]    |
[INFO] [stdout] 3  | / fn main() {
[INFO] [stdout] 4  | | use scholar::{Dataset, NeuralNet, Sigmoid};
[INFO] [stdout] 5  | |
[INFO] [stdout] 6  | | let dataset = Dataset::from_csv("iris.csv", false, 4)?;
[INFO] [stdout]    | |               ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ cannot use the `?` operator in a function that returns `()`
[INFO] [stdout] ...  |
[INFO] [stdout] 13 | | println!("Accuracy: {:.2}%", (1.0 - avg_cost) * 100.0);
[INFO] [stdout] 14 | | }
[INFO] [stdout]    | |_- this function should return `Result` or `Option` to accept `?`
[INFO] [stdout]    |
[INFO] [stdout]    = help: the trait `Try` is not implemented for `()`
[INFO] [stdout]    = note: required by `from_error`
[INFO] [stdout] 
[INFO] [stdout] error: aborting due to previous error
[INFO] [stdout] 
[INFO] [stdout] For more information about this error, try `rustc --explain E0277`.
[INFO] [stdout] Couldn't compile the test.
[INFO] [stdout] ---- src/network.rs - network::Activation::derivative (line 310) stdout ----
[INFO] [stdout] error: non-item in item list
[INFO] [stdout]  --> src/network.rs:312:5
[INFO] [stdout]   |
[INFO] [stdout] 3 | impl Activation for Sigmoid {
[INFO] [stdout]   |                             - item list starts here
[INFO] [stdout] 4 |     ...
[INFO] [stdout]   |     ^^^ non-item starts here
[INFO] [stdout] ...
[INFO] [stdout] 9 | }
[INFO] [stdout]   | - item list ends here
[INFO] [stdout] 
[INFO] [stdout] error[E0405]: cannot find trait `Activation` in this scope
[INFO] [stdout]  --> src/network.rs:311:6
[INFO] [stdout]   |
[INFO] [stdout] 3 | impl Activation for Sigmoid {
[INFO] [stdout]   |      ^^^^^^^^^^ not found in this scope
[INFO] [stdout]   |
[INFO] [stdout] help: consider importing this trait
[INFO] [stdout]   |
[INFO] [stdout] 2 | use scholar::Activation;
[INFO] [stdout]   |
[INFO] [stdout] 
[INFO] [stdout] error[E0412]: cannot find type `Sigmoid` in this scope
[INFO] [stdout]  --> src/network.rs:311:21
[INFO] [stdout]   |
[INFO] [stdout] 3 | impl Activation for Sigmoid {
[INFO] [stdout]   |                     ^^^^^^^ not found in this scope
[INFO] [stdout]   |
[INFO] [stdout] help: consider importing this struct
[INFO] [stdout]   |
[INFO] [stdout] 2 | use scholar::Sigmoid;
[INFO] [stdout]   |
[INFO] [stdout] 
[INFO] [stdout] error: aborting due to 3 previous errors
[INFO] [stdout] 
[INFO] [stdout] Some errors have detailed explanations: E0405, E0412.
[INFO] [stdout] For more information about an error, try `rustc --explain E0405`.
[INFO] [stdout] Couldn't compile the test.
[INFO] [stdout] ---- src/network.rs - network::NeuralNet<A>::save (line 164) stdout ----
[INFO] [stdout] error[E0277]: the `?` operator can only be used in a function that returns `Result` or `Option` (or another type that implements `Try`)
[INFO] [stdout]   --> src/network.rs:171:1
[INFO] [stdout]    |
[INFO] [stdout] 3  | / fn main() {
[INFO] [stdout] 4  | | use scholar::{NeuralNet, Sigmoid};
[INFO] [stdout] 5  | |
[INFO] [stdout] 6  | | let brain: NeuralNet<Sigmoid> = NeuralNet::new(&[2, 2, 1]);
[INFO] [stdout] ...  |
[INFO] [stdout] 10 | | brain.save("brain.network")?;
[INFO] [stdout]    | | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^
[INFO] [stdout]    | | |
[INFO] [stdout]    | | cannot use the `?` operator in a function that returns `()`
[INFO] [stdout] 11 | | }
[INFO] [stdout]    | |_- this function should return `Result` or `Option` to accept `?`
[INFO] [stdout]    |
[INFO] [stdout]    = help: the trait `Try` is not implemented for `()`
[INFO] [stdout]    = note: required by `from_error`
[INFO] [stdout] 
[INFO] [stdout] error: aborting due to previous error
[INFO] [stdout] 
[INFO] [stdout] For more information about this error, try `rustc --explain E0277`.
[INFO] [stdout] Couldn't compile the test.
[INFO] [stdout] ---- src/network.rs - network::Activation::derivative (line 295) stdout ----
[INFO] [stdout] error[E0425]: cannot find function `σ` in this scope
[INFO] [stdout]  --> src/network.rs:296:1
[INFO] [stdout]   |
[INFO] [stdout] 3 | σ(x) * (1 - σ(x))
[INFO] [stdout]   | ^ not found in this scope
[INFO] [stdout] 
[INFO] [stdout] error[E0425]: cannot find value `x` in this scope
[INFO] [stdout]  --> src/network.rs:296:3
[INFO] [stdout]   |
[INFO] [stdout] 3 | σ(x) * (1 - σ(x))
[INFO] [stdout]   |   ^ not found in this scope
[INFO] [stdout] 
[INFO] [stdout] error[E0425]: cannot find function `σ` in this scope
[INFO] [stdout]  --> src/network.rs:296:13
[INFO] [stdout]   |
[INFO] [stdout] 3 | σ(x) * (1 - σ(x))
[INFO] [stdout]   |             ^ not found in this scope
[INFO] [stdout] 
[INFO] [stdout] error[E0425]: cannot find value `x` in this scope
[INFO] [stdout]  --> src/network.rs:296:15
[INFO] [stdout]   |
[INFO] [stdout] 3 | σ(x) * (1 - σ(x))
[INFO] [stdout]   |               ^ not found in this scope
[INFO] [stdout] 
[INFO] [stdout] error[E0658]: non-ascii idents are not fully supported
[INFO] [stdout]  --> src/network.rs:296:1
[INFO] [stdout]   |
[INFO] [stdout] 3 | σ(x) * (1 - σ(x))
[INFO] [stdout]   | ^
[INFO] [stdout]   |
[INFO] [stdout]   = note: see issue #55467 <https://github.com/rust-lang/rust/issues/55467> for more information
[INFO] [stdout] 
[INFO] [stdout] error[E0658]: non-ascii idents are not fully supported
[INFO] [stdout]  --> src/network.rs:296:13
[INFO] [stdout]   |
[INFO] [stdout] 3 | σ(x) * (1 - σ(x))
[INFO] [stdout]   |             ^
[INFO] [stdout]   |
[INFO] [stdout]   = note: see issue #55467 <https://github.com/rust-lang/rust/issues/55467> for more information
[INFO] [stdout] 
[INFO] [stdout] warning: The usage of Script Group `Greek` in this crate consists solely of mixed script confusables
[INFO] [stdout]  --> src/network.rs:296:1
[INFO] [stdout]   |
[INFO] [stdout] 3 | σ(x) * (1 - σ(x))
[INFO] [stdout]   | ^
[INFO] [stdout]   |
[INFO] [stdout]   = note: `#[warn(mixed_script_confusables)]` on by default
[INFO] [stdout]   = note: The usage includes 'σ' (U+03C3).
[INFO] [stdout]   = note: Please recheck to make sure their usages are indeed what you want.
[INFO] [stdout] 
[INFO] [stdout] error: aborting due to 6 previous errors; 1 warning emitted
[INFO] [stdout] 
[INFO] [stdout] Some errors have detailed explanations: E0425, E0658.
[INFO] [stdout] For more information about an error, try `rustc --explain E0425`.
[INFO] [stdout] Couldn't compile the test.
[INFO] [stdout] ---- src/network.rs - network::NeuralNet<A>::train (line 88) stdout ----
[INFO] [stdout] error[E0277]: the `?` operator can only be used in a function that returns `Result` or `Option` (or another type that implements `Try`)
[INFO] [stdout]   --> src/network.rs:91:15
[INFO] [stdout]    |
[INFO] [stdout] 3  | / fn main() {
[INFO] [stdout] 4  | | use scholar::{Dataset, NeuralNet, Sigmoid};
[INFO] [stdout] 5  | |
[INFO] [stdout] 6  | | let dataset = Dataset::from_csv("iris.csv", false, 4)?;
[INFO] [stdout]    | |               ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ cannot use the `?` operator in a function that returns `()`
[INFO] [stdout] ...  |
[INFO] [stdout] 12 | | brain.train(dataset, 10_000, 0.01);
[INFO] [stdout] 13 | | }
[INFO] [stdout]    | |_- this function should return `Result` or `Option` to accept `?`
[INFO] [stdout]    |
[INFO] [stdout]    = help: the trait `Try` is not implemented for `()`
[INFO] [stdout]    = note: required by `from_error`
[INFO] [stdout] 
[INFO] [stdout] error: aborting due to previous error
[INFO] [stdout] 
[INFO] [stdout] For more information about this error, try `rustc --explain E0277`.
[INFO] [stdout] Couldn't compile the test.
[INFO] [stdout] ---- src/dataset.rs - dataset::Dataset::split (line 82) stdout ----
[INFO] [stdout] error[E0277]: the `?` operator can only be used in a function that returns `Result` or `Option` (or another type that implements `Try`)
[INFO] [stdout]  --> src/dataset.rs:83:15
[INFO] [stdout]   |
[INFO] [stdout] 3 | / fn main() {
[INFO] [stdout] 4 | | let dataset = scholar::Dataset::from_csv("iris.csv", false, 4)?;
[INFO] [stdout]   | |               ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ cannot use the `?` operator in a function that returns `()`
[INFO] [stdout] 5 | |
[INFO] [stdout] 6 | | // Randomly allocates 75% of the original dataset to `training_data`, and the rest
[INFO] [stdout] 7 | | // to `testing_data`
[INFO] [stdout] 8 | | let (training_data, testing_data) = dataset.split(0.75);
[INFO] [stdout] 9 | | }
[INFO] [stdout]   | |_- this function should return `Result` or `Option` to accept `?`
[INFO] [stdout]   |
[INFO] [stdout]   = help: the trait `Try` is not implemented for `()`
[INFO] [stdout]   = note: required by `from_error`
[INFO] [stdout] 
[INFO] [stdout] error: aborting due to previous error
[INFO] [stdout] 
[INFO] [stdout] For more information about this error, try `rustc --explain E0277`.
[INFO] [stdout] Couldn't compile the test.
[INFO] [stdout] ---- src/network.rs - network::NeuralNet<A>::from_file (line 72) stdout ----
[INFO] [stdout] error[E0277]: the `?` operator can only be used in a function that returns `Result` or `Option` (or another type that implements `Try`)
[INFO] [stdout]  --> src/network.rs:75:33
[INFO] [stdout]   |
[INFO] [stdout] 3 | / fn main() {
[INFO] [stdout] 4 | | use scholar::{NeuralNet, Sigmoid};
[INFO] [stdout] 5 | |
[INFO] [stdout] 6 | | let brain: NeuralNet<Sigmoid> = NeuralNet::from_file("brain.network")?;
[INFO] [stdout]   | |                                 ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ cannot use the `?` operator in a function that returns `()`
[INFO] [stdout] 7 | | }
[INFO] [stdout]   | |_- this function should return `Result` or `Option` to accept `?`
[INFO] [stdout]   |
[INFO] [stdout]   = help: the trait `Try` is not implemented for `()`
[INFO] [stdout]   = note: required by `from_error`
[INFO] [stdout] 
[INFO] [stdout] error: aborting due to previous error
[INFO] [stdout] 
[INFO] [stdout] For more information about this error, try `rustc --explain E0277`.
[INFO] [stdout] Couldn't compile the test.
[INFO] [stdout] 
[INFO] [stdout] failures:
[INFO] [stdout]     src/dataset.rs - dataset::Dataset::split (line 82)
[INFO] [stdout]     src/network.rs - network::Activation::derivative (line 295)
[INFO] [stdout]     src/network.rs - network::Activation::derivative (line 304)
[INFO] [stdout]     src/network.rs - network::Activation::derivative (line 310)
[INFO] [stdout]     src/network.rs - network::NeuralNet<A>::from_file (line 72)
[INFO] [stdout]     src/network.rs - network::NeuralNet<A>::save (line 164)
[INFO] [stdout]     src/network.rs - network::NeuralNet<A>::test (line 130)
[INFO] [stdout]     src/network.rs - network::NeuralNet<A>::train (line 88)
[INFO] [stdout] 
[INFO] [stdout] test result: FAILED. 6 passed; 8 failed; 0 ignored; 0 measured; 0 filtered out
[INFO] [stdout] 
[INFO] [stderr] error: test failed, to rerun pass '--doc'
[INFO] running `Command { std: "docker" "inspect" "143dbe0b133cbb984a994ca93ffd823c7941be8873be316bc8770733018e604f", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "143dbe0b133cbb984a994ca93ffd823c7941be8873be316bc8770733018e604f", kill_on_drop: false }`
[INFO] [stdout] 143dbe0b133cbb984a994ca93ffd823c7941be8873be316bc8770733018e604f
