[INFO] fetching crate atsamd21-hal 0.3.1...
[INFO] checking atsamd21-hal-0.3.1 against master#0dce3f606e05cffab7361c132a399d3550ab0df8 for pr-78376
[INFO] extracting crate atsamd21-hal 0.3.1 into /workspace/builds/worker-6/source
[INFO] validating manifest of crates.io crate atsamd21-hal 0.3.1 on toolchain 0dce3f606e05cffab7361c132a399d3550ab0df8
[INFO] running `Command { std: "/workspace/cargo-home/bin/cargo" "+0dce3f606e05cffab7361c132a399d3550ab0df8" "read-manifest" "--manifest-path" "Cargo.toml", kill_on_drop: false }`
[INFO] started tweaking crates.io crate atsamd21-hal 0.3.1
[INFO] finished tweaking crates.io crate atsamd21-hal 0.3.1
[INFO] tweaked toml for crates.io crate atsamd21-hal 0.3.1 written to /workspace/builds/worker-6/source/Cargo.toml
[INFO] running `Command { std: "/workspace/cargo-home/bin/cargo" "+0dce3f606e05cffab7361c132a399d3550ab0df8" "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" "+0dce3f606e05cffab7361c132a399d3550ab0df8" "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-6/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-6/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" "+0dce3f606e05cffab7361c132a399d3550ab0df8" "metadata" "--no-deps" "--format-version=1", kill_on_drop: false }`
[INFO] [stdout] c3d0dfa42f5ed5a3e5c71a1980e1198c12053899609b90007d0dc4d84d359916
[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" "c3d0dfa42f5ed5a3e5c71a1980e1198c12053899609b90007d0dc4d84d359916", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "inspect" "c3d0dfa42f5ed5a3e5c71a1980e1198c12053899609b90007d0dc4d84d359916", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "c3d0dfa42f5ed5a3e5c71a1980e1198c12053899609b90007d0dc4d84d359916", kill_on_drop: false }`
[INFO] [stdout] c3d0dfa42f5ed5a3e5c71a1980e1198c12053899609b90007d0dc4d84d359916
[INFO] running `Command { std: "docker" "create" "-v" "/var/lib/crater-agent-workspace/builds/worker-6/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-6/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:d92eaeed33fa75130ca1ee6c8a01d1ffb62bac859dfdfb3450e3e5d1c0146529" "/opt/rustwide/cargo-home/bin/cargo" "+0dce3f606e05cffab7361c132a399d3550ab0df8" "check" "--frozen" "--all" "--all-targets" "--message-format=json", 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] 447e2904ae5fd016af5aca1021d8d02ab87367c014c1afecbc8ccafff06b68e4
[INFO] running `Command { std: "docker" "start" "-a" "447e2904ae5fd016af5aca1021d8d02ab87367c014c1afecbc8ccafff06b68e4", kill_on_drop: false }`
[INFO] [stderr]    Compiling typenum v1.12.0
[INFO] [stderr]    Compiling version_check v0.9.2
[INFO] [stderr]    Compiling semver-parser v0.7.0
[INFO] [stderr]    Compiling cortex-m v0.6.4
[INFO] [stderr]     Checking vcell v0.1.2
[INFO] [stderr]     Checking stable_deref_trait v1.2.0
[INFO] [stderr]    Compiling proc-macro2 v0.4.30
[INFO] [stderr]    Compiling libc v0.2.80
[INFO] [stderr]     Checking bitfield v0.13.2
[INFO] [stderr]    Compiling cfg-if v1.0.0
[INFO] [stderr]    Compiling cortex-m v0.5.10
[INFO] [stderr]     Checking aligned v0.2.0
[INFO] [stderr]    Compiling cortex-m-semihosting v0.3.5
[INFO] [stderr]    Compiling cortex-m v0.4.3
[INFO] [stderr]    Compiling cortex-m-rtfm v0.3.4
[INFO] [stderr]     Checking untagged-option v0.1.1
[INFO] [stderr]     Checking bare-metal v0.1.3
[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] 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] [stderr] error: build failed
[INFO] running `Command { std: "docker" "inspect" "447e2904ae5fd016af5aca1021d8d02ab87367c014c1afecbc8ccafff06b68e4", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "447e2904ae5fd016af5aca1021d8d02ab87367c014c1afecbc8ccafff06b68e4", kill_on_drop: false }`
[INFO] [stdout] 447e2904ae5fd016af5aca1021d8d02ab87367c014c1afecbc8ccafff06b68e4