[INFO] fetching crate buspirate 0.1.0...
[INFO] testing buspirate-0.1.0 against beta-2021-08-01 for beta-1.55-1
[INFO] extracting crate buspirate 0.1.0 into /workspace/builds/worker-77/source
[INFO] validating manifest of crates.io crate buspirate 0.1.0 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 crates.io crate buspirate 0.1.0
[INFO] finished tweaking crates.io crate buspirate 0.1.0
[INFO] tweaked toml for crates.io crate buspirate 0.1.0 written to /workspace/builds/worker-77/source/Cargo.toml
[INFO] running `Command { std: "/workspace/cargo-home/bin/cargo" "+beta-2021-08-01" "generate-lockfile" "--manifest-path" "Cargo.toml" "-Zno-index-update", kill_on_drop: false }`
[INFO] [stderr]     Blocking waiting for file lock on package cache
[INFO] running `Command { std: "/workspace/cargo-home/bin/cargo" "+beta-2021-08-01" "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-77/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-77/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] e14cb240c96ea1e1f393855223a682fcd2d4da674955ecb7272ec735f19e7bf0
[INFO] running `Command { std: "docker" "start" "-a" "e14cb240c96ea1e1f393855223a682fcd2d4da674955ecb7272ec735f19e7bf0", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "inspect" "e14cb240c96ea1e1f393855223a682fcd2d4da674955ecb7272ec735f19e7bf0", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "e14cb240c96ea1e1f393855223a682fcd2d4da674955ecb7272ec735f19e7bf0", kill_on_drop: false }`
[INFO] [stdout] e14cb240c96ea1e1f393855223a682fcd2d4da674955ecb7272ec735f19e7bf0
[INFO] running `Command { std: "docker" "create" "-v" "/var/lib/crater-agent-workspace/builds/worker-77/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-77/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] 06b990ac553297eb9ab9ccb77b1207f9e6303707900e9cbb8345789eeddbf0ac
[INFO] running `Command { std: "docker" "start" "-a" "06b990ac553297eb9ab9ccb77b1207f9e6303707900e9cbb8345789eeddbf0ac", kill_on_drop: false }`
[INFO] [stderr]    Compiling nb v1.0.0
[INFO] [stderr]    Compiling void v1.0.2
[INFO] [stderr]    Compiling nb v0.1.3
[INFO] [stderr]    Compiling embedded-hal v0.2.6
[INFO] [stderr]    Compiling buspirate v0.1.0 (/opt/rustwide/workdir)
[INFO] [stderr]     Finished dev [unoptimized + debuginfo] target(s) in 0.81s
[INFO] running `Command { std: "docker" "inspect" "06b990ac553297eb9ab9ccb77b1207f9e6303707900e9cbb8345789eeddbf0ac", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "06b990ac553297eb9ab9ccb77b1207f9e6303707900e9cbb8345789eeddbf0ac", kill_on_drop: false }`
[INFO] [stdout] 06b990ac553297eb9ab9ccb77b1207f9e6303707900e9cbb8345789eeddbf0ac
[INFO] running `Command { std: "docker" "create" "-v" "/var/lib/crater-agent-workspace/builds/worker-77/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-77/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" "test" "--frozen" "--no-run" "--message-format=json", kill_on_drop: false }`
[INFO] [stdout] d2fa31ed38a78abe5fe0a35d8924969f836c41c5ab62df0207242b95445b1792
[INFO] running `Command { std: "docker" "start" "-a" "d2fa31ed38a78abe5fe0a35d8924969f836c41c5ab62df0207242b95445b1792", kill_on_drop: false }`
[INFO] [stderr]    Compiling buspirate v0.1.0 (/opt/rustwide/workdir)
[INFO] [stderr]     Finished test [unoptimized + debuginfo] target(s) in 2.20s
[INFO] running `Command { std: "docker" "inspect" "d2fa31ed38a78abe5fe0a35d8924969f836c41c5ab62df0207242b95445b1792", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "d2fa31ed38a78abe5fe0a35d8924969f836c41c5ab62df0207242b95445b1792", kill_on_drop: false }`
[INFO] [stdout] d2fa31ed38a78abe5fe0a35d8924969f836c41c5ab62df0207242b95445b1792
[INFO] running `Command { std: "docker" "create" "-v" "/var/lib/crater-agent-workspace/builds/worker-77/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-77/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" "test" "--frozen", kill_on_drop: false }`
[INFO] [stdout] bea6b23069fef50fdab3a0b30cd2896d4167b111ee813de836e87adcc1c0832e
[INFO] running `Command { std: "docker" "start" "-a" "bea6b23069fef50fdab3a0b30cd2896d4167b111ee813de836e87adcc1c0832e", kill_on_drop: false }`
[INFO] [stderr]     Blocking waiting for file lock on package cache
[INFO] [stderr]     Finished test [unoptimized + debuginfo] target(s) in 0.86s
[INFO] [stderr]      Running unittests (/opt/rustwide/target/debug/deps/buspirate-a6e2e615f2c256df)
[INFO] [stdout] 
[INFO] [stderr]    Doc-tests buspirate
[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] [stdout] 
[INFO] [stdout] running 6 tests
[INFO] [stdout] test src/lib.rs - (line 49) ... FAILED
[INFO] [stdout] test src/lib.rs - BusPirate (line 72) ... FAILED
[INFO] [stdout] test src/bitbang.rs - bitbang (line 6) ... FAILED
[INFO] [stdout] test src/lib.rs - (line 22) ... FAILED
[INFO] [stdout] test src/spi.rs - spi (line 7) ... FAILED
[INFO] [stdout] test src/lib.rs - (line 41) ... FAILED
[INFO] [stdout] 
[INFO] [stdout] failures:
[INFO] [stdout] 
[INFO] [stdout] ---- src/lib.rs - (line 49) stdout ----
[INFO] [stdout] error[E0425]: cannot find value `bp` in this scope
[INFO] [stdout]  --> src/lib.rs:50:11
[INFO] [stdout]   |
[INFO] [stdout] 3 | let spi = bp.to_spi()?;
[INFO] [stdout]   |           ^^ not found in this scope
[INFO] [stdout] 
[INFO] [stdout] error[E0277]: the `?` operator can only be used in a function that returns `Result` or `Option` (or another type that implements `FromResidual`)
[INFO] [stdout]    --> src/lib.rs:50:22
[INFO] [stdout]     |
[INFO] [stdout] 2   |   fn main() { #[allow(non_snake_case)] fn _doctest_main_src_lib_rs_49_0() {
[INFO] [stdout]     |  ______________________________________-
[INFO] [stdout] 3   | | let spi = bp.to_spi()?;
[INFO] [stdout]     | |                      ^ cannot use the `?` operator in a function that returns `()`
[INFO] [stdout] 4   | | } _doctest_main_src_lib_rs_49_0() }
[INFO] [stdout]     | |_- this function should return `Result` or `Option` to accept `?`
[INFO] [stdout]     |
[INFO] [stdout]     = help: the trait `FromResidual<_>` is not implemented for `()`
[INFO] [stdout] note: required by `from_residual`
[INFO] [stdout] 
[INFO] [stdout] error: aborting due to 2 previous errors
[INFO] [stdout] 
[INFO] [stdout] Some errors have detailed explanations: E0277, E0425.
[INFO] [stdout] For more information about an error, try `rustc --explain E0277`.
[INFO] [stdout] Couldn't compile the test.
[INFO] [stdout] ---- src/lib.rs - BusPirate (line 72) stdout ----
[INFO] [stdout] error[E0425]: cannot find value `bp` in this scope
[INFO] [stdout]  --> src/lib.rs:73:10
[INFO] [stdout]   |
[INFO] [stdout] 3 | let bb = bp.to_bitbang()?;
[INFO] [stdout]   |          ^^ not found in this scope
[INFO] [stdout] 
[INFO] [stdout] error[E0277]: the `?` operator can only be used in a function that returns `Result` or `Option` (or another type that implements `FromResidual`)
[INFO] [stdout]    --> src/lib.rs:73:25
[INFO] [stdout]     |
[INFO] [stdout] 2   |   fn main() { #[allow(non_snake_case)] fn _doctest_main_src_lib_rs_72_0() {
[INFO] [stdout]     |  ______________________________________-
[INFO] [stdout] 3   | | let bb = bp.to_bitbang()?;
[INFO] [stdout]     | |                         ^ cannot use the `?` operator in a function that returns `()`
[INFO] [stdout] 4   | | } _doctest_main_src_lib_rs_72_0() }
[INFO] [stdout]     | |_- this function should return `Result` or `Option` to accept `?`
[INFO] [stdout]     |
[INFO] [stdout]     = help: the trait `FromResidual<_>` is not implemented for `()`
[INFO] [stdout] note: required by `from_residual`
[INFO] [stdout] 
[INFO] [stdout] error: aborting due to 2 previous errors
[INFO] [stdout] 
[INFO] [stdout] Some errors have detailed explanations: E0277, E0425.
[INFO] [stdout] For more information about an error, try `rustc --explain E0277`.
[INFO] [stdout] Couldn't compile the test.
[INFO] [stdout] ---- src/bitbang.rs - bitbang (line 6) stdout ----
[INFO] [stdout] error[E0433]: failed to resolve: use of undeclared type `BusPirate`
[INFO] [stdout]  --> src/bitbang.rs:7:10
[INFO] [stdout]   |
[INFO] [stdout] 3 | let bp = BusPirate::new();
[INFO] [stdout]   |          ^^^^^^^^^ not found in this scope
[INFO] [stdout]   |
[INFO] [stdout] help: consider importing this struct
[INFO] [stdout]   |
[INFO] [stdout] 2 | use buspirate::BusPirate;
[INFO] [stdout]   |
[INFO] [stdout] 
[INFO] [stdout] error[E0277]: the `?` operator can only be used in a function that returns `Result` or `Option` (or another type that implements `FromResidual`)
[INFO] [stdout]    --> src/bitbang.rs:8:25
[INFO] [stdout]     |
[INFO] [stdout] 2   |   fn main() { #[allow(non_snake_case)] fn _doctest_main_src_bitbang_rs_6_0() {
[INFO] [stdout]     |  ______________________________________-
[INFO] [stdout] 3   | | let bp = BusPirate::new();
[INFO] [stdout] 4   | | let bb = bp.to_bitbang()?;
[INFO] [stdout]     | |                         ^ cannot use the `?` operator in a function that returns `()`
[INFO] [stdout] 5   | | } _doctest_main_src_bitbang_rs_6_0() }
[INFO] [stdout]     | |_- this function should return `Result` or `Option` to accept `?`
[INFO] [stdout]     |
[INFO] [stdout]     = help: the trait `FromResidual<_>` is not implemented for `()`
[INFO] [stdout] note: required by `from_residual`
[INFO] [stdout] 
[INFO] [stdout] error: aborting due to 2 previous errors
[INFO] [stdout] 
[INFO] [stdout] Some errors have detailed explanations: E0277, E0433.
[INFO] [stdout] For more information about an error, try `rustc --explain E0277`.
[INFO] [stdout] Couldn't compile the test.
[INFO] [stdout] ---- src/lib.rs - (line 22) stdout ----
[INFO] [stdout] error[E0433]: failed to resolve: use of undeclared type `Serial`
[INFO] [stdout]  --> src/lib.rs:23:12
[INFO] [stdout]   |
[INFO] [stdout] 3 | let port = Serial::new(
[INFO] [stdout]   |            ^^^^^^ use of undeclared type `Serial`
[INFO] [stdout] 
[INFO] [stdout] error[E0433]: failed to resolve: use of undeclared crate or module `serial_embedded_hal`
[INFO] [stdout]  --> src/lib.rs:26:20
[INFO] [stdout]   |
[INFO] [stdout] 6 |         baud_rate: serial_embedded_hal::BaudRate::Baud115200,
[INFO] [stdout]   |                    ^^^^^^^^^^^^^^^^^^^ use of undeclared crate or module `serial_embedded_hal`
[INFO] [stdout] 
[INFO] [stdout] error[E0433]: failed to resolve: use of undeclared crate or module `serial_embedded_hal`
[INFO] [stdout]  --> src/lib.rs:27:20
[INFO] [stdout]   |
[INFO] [stdout] 7 |         char_size: serial_embedded_hal::CharSize::Bits8,
[INFO] [stdout]   |                    ^^^^^^^^^^^^^^^^^^^ use of undeclared crate or module `serial_embedded_hal`
[INFO] [stdout] 
[INFO] [stdout] error[E0433]: failed to resolve: use of undeclared crate or module `serial_embedded_hal`
[INFO] [stdout]  --> src/lib.rs:28:17
[INFO] [stdout]   |
[INFO] [stdout] 8 |         parity: serial_embedded_hal::Parity::ParityNone,
[INFO] [stdout]   |                 ^^^^^^^^^^^^^^^^^^^ use of undeclared crate or module `serial_embedded_hal`
[INFO] [stdout] 
[INFO] [stdout] error[E0433]: failed to resolve: use of undeclared crate or module `serial_embedded_hal`
[INFO] [stdout]  --> src/lib.rs:29:20
[INFO] [stdout]   |
[INFO] [stdout] 9 |         stop_bits: serial_embedded_hal::StopBits::Stop1,
[INFO] [stdout]   |                    ^^^^^^^^^^^^^^^^^^^ use of undeclared crate or module `serial_embedded_hal`
[INFO] [stdout] 
[INFO] [stdout] error[E0433]: failed to resolve: use of undeclared crate or module `serial_embedded_hal`
[INFO] [stdout]   --> src/lib.rs:30:23
[INFO] [stdout]    |
[INFO] [stdout] 10 |         flow_control: serial_embedded_hal::FlowControl::FlowNone,
[INFO] [stdout]    |                       ^^^^^^^^^^^^^^^^^^^ use of undeclared crate or module `serial_embedded_hal`
[INFO] [stdout] 
[INFO] [stdout] error[E0422]: cannot find struct, variant or union type `PortSettings` in this scope
[INFO] [stdout]  --> src/lib.rs:25:6
[INFO] [stdout]   |
[INFO] [stdout] 5 |     &PortSettings {
[INFO] [stdout]   |      ^^^^^^^^^^^^ not found in this scope
[INFO] [stdout] 
[INFO] [stdout] error[E0433]: failed to resolve: use of undeclared type `BusPirate`
[INFO] [stdout]   --> src/lib.rs:34:10
[INFO] [stdout]    |
[INFO] [stdout] 14 | let bp = BusPirate::new(tx, rx);
[INFO] [stdout]    |          ^^^^^^^^^ not found in this scope
[INFO] [stdout]    |
[INFO] [stdout] help: consider importing this struct
[INFO] [stdout]    |
[INFO] [stdout] 2  | use buspirate::BusPirate;
[INFO] [stdout]    |
[INFO] [stdout] 
[INFO] [stdout] error[E0277]: the `?` operator can only be used in a function that returns `Result` or `Option` (or another type that implements `FromResidual`)
[INFO] [stdout]    --> src/lib.rs:32:2
[INFO] [stdout]     |
[INFO] [stdout] 2   |   fn main() { #[allow(non_snake_case)] fn _doctest_main_src_lib_rs_22_0() {
[INFO] [stdout]     |  ______________________________________-
[INFO] [stdout] 3   | | let port = Serial::new(
[INFO] [stdout] 4   | |     "/dev/ttyUSB0",
[INFO] [stdout] 5   | |     &PortSettings {
[INFO] [stdout] ...   |
[INFO] [stdout] 12  | | )?;
[INFO] [stdout]     | |  ^ cannot use the `?` operator in a function that returns `()`
[INFO] [stdout] 13  | | let (tx, rx) = port.split();
[INFO] [stdout] 14  | | let bp = BusPirate::new(tx, rx);
[INFO] [stdout] 15  | | } _doctest_main_src_lib_rs_22_0() }
[INFO] [stdout]     | |_- this function should return `Result` or `Option` to accept `?`
[INFO] [stdout]     |
[INFO] [stdout]     = help: the trait `FromResidual<_>` is not implemented for `()`
[INFO] [stdout] note: required by `from_residual`
[INFO] [stdout] 
[INFO] [stdout] error: aborting due to 9 previous errors
[INFO] [stdout] 
[INFO] [stdout] Some errors have detailed explanations: E0277, E0422, E0433.
[INFO] [stdout] For more information about an error, try `rustc --explain E0277`.
[INFO] [stdout] Couldn't compile the test.
[INFO] [stdout] ---- src/spi.rs - spi (line 7) stdout ----
[INFO] [stdout] error[E0433]: failed to resolve: use of undeclared type `BusPirate`
[INFO] [stdout]  --> src/spi.rs:8:10
[INFO] [stdout]   |
[INFO] [stdout] 3 | let bp = BusPirate::new();
[INFO] [stdout]   |          ^^^^^^^^^ not found in this scope
[INFO] [stdout]   |
[INFO] [stdout] help: consider importing this struct
[INFO] [stdout]   |
[INFO] [stdout] 2 | use buspirate::BusPirate;
[INFO] [stdout]   |
[INFO] [stdout] 
[INFO] [stdout] error[E0277]: the `?` operator can only be used in a function that returns `Result` or `Option` (or another type that implements `FromResidual`)
[INFO] [stdout]    --> src/spi.rs:9:25
[INFO] [stdout]     |
[INFO] [stdout] 2   |   fn main() { #[allow(non_snake_case)] fn _doctest_main_src_spi_rs_7_0() {
[INFO] [stdout]     |  ______________________________________-
[INFO] [stdout] 3   | | let bp = BusPirate::new();
[INFO] [stdout] 4   | | let bb = bp.to_bitbang()?;
[INFO] [stdout]     | |                         ^ cannot use the `?` operator in a function that returns `()`
[INFO] [stdout] 5   | | let bspi = bb.to_spi()?;
[INFO] [stdout] 6   | | } _doctest_main_src_spi_rs_7_0() }
[INFO] [stdout]     | |_- this function should return `Result` or `Option` to accept `?`
[INFO] [stdout]     |
[INFO] [stdout]     = help: the trait `FromResidual<_>` is not implemented for `()`
[INFO] [stdout] note: required by `from_residual`
[INFO] [stdout] 
[INFO] [stdout] error[E0277]: the `?` operator can only be used in a function that returns `Result` or `Option` (or another type that implements `FromResidual`)
[INFO] [stdout]    --> src/spi.rs:10:23
[INFO] [stdout]     |
[INFO] [stdout] 2   |   fn main() { #[allow(non_snake_case)] fn _doctest_main_src_spi_rs_7_0() {
[INFO] [stdout]     |  ______________________________________-
[INFO] [stdout] 3   | | let bp = BusPirate::new();
[INFO] [stdout] 4   | | let bb = bp.to_bitbang()?;
[INFO] [stdout] 5   | | let bspi = bb.to_spi()?;
[INFO] [stdout]     | |                       ^ cannot use the `?` operator in a function that returns `()`
[INFO] [stdout] 6   | | } _doctest_main_src_spi_rs_7_0() }
[INFO] [stdout]     | |_- this function should return `Result` or `Option` to accept `?`
[INFO] [stdout]     |
[INFO] [stdout]     = help: the trait `FromResidual<_>` is not implemented for `()`
[INFO] [stdout] note: required by `from_residual`
[INFO] [stdout] 
[INFO] [stdout] error: aborting due to 3 previous errors
[INFO] [stdout] 
[INFO] [stdout] Some errors have detailed explanations: E0277, E0433.
[INFO] [stdout] For more information about an error, try `rustc --explain E0277`.
[INFO] [stdout] Couldn't compile the test.
[INFO] [stdout] ---- src/lib.rs - (line 41) stdout ----
[INFO] [stdout] error[E0425]: cannot find value `bp` in this scope
[INFO] [stdout]  --> src/lib.rs:42:10
[INFO] [stdout]   |
[INFO] [stdout] 3 | let bb = bp.init()?;
[INFO] [stdout]   |          ^^ not found in this scope
[INFO] [stdout] 
[INFO] [stdout] error[E0277]: the `?` operator can only be used in a function that returns `Result` or `Option` (or another type that implements `FromResidual`)
[INFO] [stdout]    --> src/lib.rs:42:19
[INFO] [stdout]     |
[INFO] [stdout] 2   |   fn main() { #[allow(non_snake_case)] fn _doctest_main_src_lib_rs_41_0() {
[INFO] [stdout]     |  ______________________________________-
[INFO] [stdout] 3   | | let bb = bp.init()?;
[INFO] [stdout]     | |                   ^ cannot use the `?` operator in a function that returns `()`
[INFO] [stdout] 4   | | } _doctest_main_src_lib_rs_41_0() }
[INFO] [stdout]     | |_- this function should return `Result` or `Option` to accept `?`
[INFO] [stdout]     |
[INFO] [stdout]     = help: the trait `FromResidual<_>` is not implemented for `()`
[INFO] [stdout] note: required by `from_residual`
[INFO] [stdout] 
[INFO] [stdout] error: aborting due to 2 previous errors
[INFO] [stdout] 
[INFO] [stdout] Some errors have detailed explanations: E0277, E0425.
[INFO] [stdout] For more information about an error, try `rustc --explain E0277`.
[INFO] [stdout] Couldn't compile the test.
[INFO] [stdout] 
[INFO] [stdout] failures:
[INFO] [stdout]     src/bitbang.rs - bitbang (line 6)
[INFO] [stdout]     src/lib.rs - (line 22)
[INFO] [stdout]     src/lib.rs - (line 41)
[INFO] [stdout]     src/lib.rs - (line 49)
[INFO] [stdout]     src/lib.rs - BusPirate (line 72)
[INFO] [stdout]     src/spi.rs - spi (line 7)
[INFO] [stdout] 
[INFO] [stdout] test result: FAILED. 0 passed; 6 failed; 0 ignored; 0 measured; 0 filtered out; finished in 0.34s
[INFO] [stdout] 
[INFO] [stderr] error: test failed, to rerun pass '--doc'
[INFO] running `Command { std: "docker" "inspect" "bea6b23069fef50fdab3a0b30cd2896d4167b111ee813de836e87adcc1c0832e", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "bea6b23069fef50fdab3a0b30cd2896d4167b111ee813de836e87adcc1c0832e", kill_on_drop: false }`
[INFO] [stdout] bea6b23069fef50fdab3a0b30cd2896d4167b111ee813de836e87adcc1c0832e
