[INFO] fetching crate keymatrix 0.1.2...
[INFO] checking keymatrix-0.1.2 against master#7b3a7819371cef92a187e9bac8f7810ccde15216 for pr-74846
[INFO] extracting crate keymatrix 0.1.2 into /workspace/builds/worker-4/source
[INFO] validating manifest of crates.io crate keymatrix 0.1.2 on toolchain 7b3a7819371cef92a187e9bac8f7810ccde15216
[INFO] running `Command { std: "/workspace/cargo-home/bin/cargo" "+7b3a7819371cef92a187e9bac8f7810ccde15216" "read-manifest" "--manifest-path" "Cargo.toml", kill_on_drop: false }`
[INFO] started tweaking crates.io crate keymatrix 0.1.2
[INFO] finished tweaking crates.io crate keymatrix 0.1.2
[INFO] tweaked toml for crates.io crate keymatrix 0.1.2 written to /workspace/builds/worker-4/source/Cargo.toml
[INFO] running `Command { std: "/workspace/cargo-home/bin/cargo" "+7b3a7819371cef92a187e9bac8f7810ccde15216" "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" "+7b3a7819371cef92a187e9bac8f7810ccde15216" "fetch" "--locked" "--manifest-path" "Cargo.toml", kill_on_drop: false }`
[INFO] [stderr]     Blocking waiting for file lock on package cache
[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" "rustops/crates-build-env@sha256:a636fd89d022f18117e1dc8fb37a0a009933cdbbe082814857f0e2024962d47c" "/opt/rustwide/cargo-home/bin/cargo" "+7b3a7819371cef92a187e9bac8f7810ccde15216" "metadata" "--no-deps" "--format-version=1", kill_on_drop: false }`
[INFO] [stdout] e4f57f3efaf91ba93395a10b5c79663819c95ae61cbfb3b4158cad8efec92224
[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" "e4f57f3efaf91ba93395a10b5c79663819c95ae61cbfb3b4158cad8efec92224", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "inspect" "e4f57f3efaf91ba93395a10b5c79663819c95ae61cbfb3b4158cad8efec92224", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "e4f57f3efaf91ba93395a10b5c79663819c95ae61cbfb3b4158cad8efec92224", kill_on_drop: false }`
[INFO] [stdout] e4f57f3efaf91ba93395a10b5c79663819c95ae61cbfb3b4158cad8efec92224
[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=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" "rustops/crates-build-env@sha256:a636fd89d022f18117e1dc8fb37a0a009933cdbbe082814857f0e2024962d47c" "/opt/rustwide/cargo-home/bin/cargo" "+7b3a7819371cef92a187e9bac8f7810ccde15216" "check" "--frozen" "--all" "--all-targets" "--message-format=json", kill_on_drop: false }`
[INFO] [stdout] b98a23d37d90343e4f0c0393a39ce7e9b4d56a7327fd1dd8e07e36182637c43a
[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" "b98a23d37d90343e4f0c0393a39ce7e9b4d56a7327fd1dd8e07e36182637c43a", kill_on_drop: false }`
[INFO] [stderr]    Compiling proc-macro2 v1.0.19
[INFO] [stderr]    Compiling typenum v1.12.0
[INFO] [stderr]    Compiling unicode-xid v0.2.1
[INFO] [stderr]    Compiling syn v1.0.38
[INFO] [stderr]    Compiling unicode-xid v0.1.0
[INFO] [stderr]    Compiling cortex-m v0.5.10
[INFO] [stderr]     Checking aligned v0.2.0
[INFO] [stderr]    Compiling failure_derive v0.1.8
[INFO] [stderr]    Compiling adler v0.2.3
[INFO] [stderr]    Compiling gimli v0.22.0
[INFO] [stderr]     Checking nb v1.0.0
[INFO] [stderr]     Checking void v1.0.2
[INFO] [stderr]    Compiling cfg-if v0.1.10
[INFO] [stderr]    Compiling object v0.20.0
[INFO] [stderr]    Compiling rustc-demangle v0.1.16
[INFO] [stderr]     Checking aligned v0.1.2
[INFO] [stderr]    Compiling proc-macro-hack v0.5.18
[INFO] [stderr]    Compiling atsamd21g18a v0.4.0
[INFO] [stderr]     Checking bare-metal v0.1.3
[INFO] [stderr]    Compiling cortex-m v0.4.3
[INFO] [stderr]    Compiling atsamd21g18a v0.3.1
[INFO] [stderr]    Compiling either v1.6.0
[INFO] [stderr]    Compiling cortex-m v0.3.1
[INFO] [stderr]    Compiling cortex-m-rtfm v0.3.4
[INFO] [stderr]     Checking untagged-option v0.1.1
[INFO] [stderr]     Checking rtfm-core v0.2.0
[INFO] [stdout] error[E0740]: unions may not contain fields that need dropping
[INFO] [stdout]   --> /opt/rustwide/cargo-home/registry/src/github.com-1ecc6299db9ec823/untagged-option-0.1.1/src/lib.rs:53:5
[INFO] [stdout]    |
[INFO] [stdout] 53 |     pub some: T,
[INFO] [stdout]    |     ^^^^^^^^^^^
[INFO] [stdout]    |
[INFO] [stdout] note: `std::mem::ManuallyDrop` can be used to wrap the type
[INFO] [stdout]   --> /opt/rustwide/cargo-home/registry/src/github.com-1ecc6299db9ec823/untagged-option-0.1.1/src/lib.rs:53:5
[INFO] [stdout]    |
[INFO] [stdout] 53 |     pub some: T,
[INFO] [stdout]    |     ^^^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] error: aborting due to previous error
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] For more information about this error, try `rustc --explain E0740`.
[INFO] [stdout] 
[INFO] [stderr]     Checking panic-abort v0.2.0
[INFO] [stderr] error: could not compile `untagged-option`.
[INFO] [stderr] 
[INFO] [stderr] To learn more, run the command again with --verbose.
[INFO] [stderr] warning: build failed, waiting for other jobs to finish...
[INFO] [stdout] error[E0557]: feature has been removed
[INFO] [stdout]   --> /opt/rustwide/cargo-home/registry/src/github.com-1ecc6299db9ec823/panic-abort-0.2.0/src/lib.rs:22:12
[INFO] [stdout]    |
[INFO] [stdout] 22 | #![feature(panic_implementation)]
[INFO] [stdout]    |            ^^^^^^^^^^^^^^^^^^^^ feature has been removed
[INFO] [stdout]    |
[INFO] [stdout]    = note: subsumed by `#[panic_handler]`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] error: cannot find attribute `panic_implementation` in this scope
[INFO] [stdout]   --> /opt/rustwide/cargo-home/registry/src/github.com-1ecc6299db9ec823/panic-abort-0.2.0/src/lib.rs:28:3
[INFO] [stdout]    |
[INFO] [stdout] 28 | #[panic_implementation]
[INFO] [stdout]    |   ^^^^^^^^^^^^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] error: aborting due to 2 previous errors
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] For more information about this error, try `rustc --explain E0557`.
[INFO] [stdout] 
[INFO] [stderr] error: build failed
[INFO] running `Command { std: "docker" "inspect" "b98a23d37d90343e4f0c0393a39ce7e9b4d56a7327fd1dd8e07e36182637c43a", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "b98a23d37d90343e4f0c0393a39ce7e9b4d56a7327fd1dd8e07e36182637c43a", kill_on_drop: false }`
[INFO] [stdout] b98a23d37d90343e4f0c0393a39ce7e9b4d56a7327fd1dd8e07e36182637c43a