[INFO] fetching crate magic-wormhole 0.0.2...
[INFO] documenting magic-wormhole-0.0.2 against beta-2020-08-29 for beta-1.47-rustdoc-1
[INFO] extracting crate magic-wormhole 0.0.2 into /workspace/builds/worker-12/source
[INFO] validating manifest of crates.io crate magic-wormhole 0.0.2 on toolchain beta-2020-08-29
[INFO] running `Command { std: "/workspace/cargo-home/bin/cargo" "+beta-2020-08-29" "read-manifest" "--manifest-path" "Cargo.toml", kill_on_drop: false }`
[INFO] started tweaking crates.io crate magic-wormhole 0.0.2
[INFO] finished tweaking crates.io crate magic-wormhole 0.0.2
[INFO] tweaked toml for crates.io crate magic-wormhole 0.0.2 written to /workspace/builds/worker-12/source/Cargo.toml
[INFO] crate crates.io crate magic-wormhole 0.0.2 already has a lockfile, it will not be regenerated
[INFO] running `Command { std: "/workspace/cargo-home/bin/cargo" "+beta-2020-08-29" "fetch" "--locked" "--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] [stderr]  Downloading crates ...
[INFO] [stderr]   Downloaded spake2 v0.2.0
[INFO] [stderr]   Downloaded rustyline v5.0.2
[INFO] running `Command { std: "docker" "create" "-v" "/var/lib/crater-agent-workspace/builds/worker-12/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-12/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-2020-08-29" "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] d10354b959b48a94783e0b1c7ef3c9c69c0e42319c3f8b18b8865ad64412d278
[INFO] running `Command { std: "docker" "start" "-a" "d10354b959b48a94783e0b1c7ef3c9c69c0e42319c3f8b18b8865ad64412d278", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "inspect" "d10354b959b48a94783e0b1c7ef3c9c69c0e42319c3f8b18b8865ad64412d278", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "d10354b959b48a94783e0b1c7ef3c9c69c0e42319c3f8b18b8865ad64412d278", kill_on_drop: false }`
[INFO] [stdout] d10354b959b48a94783e0b1c7ef3c9c69c0e42319c3f8b18b8865ad64412d278
[INFO] running `Command { std: "docker" "create" "-v" "/var/lib/crater-agent-workspace/builds/worker-12/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-12/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" "RUSTDOCFLAGS=--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-2020-08-29" "doc" "--frozen" "--no-deps" "--document-private-items" "--message-format=json", kill_on_drop: false }`
[INFO] [stdout] 9534a5d02d8a60872267a839fb740c50a2069ca4276e033302feb2981ce973b2
[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" "9534a5d02d8a60872267a839fb740c50a2069ca4276e033302feb2981ce973b2", kill_on_drop: false }`
[INFO] [stderr]    Compiling byteorder v1.3.2
[INFO] [stderr]    Compiling cc v1.0.41
[INFO] [stderr]    Compiling getrandom v0.1.11
[INFO] [stderr]    Compiling subtle v2.1.1
[INFO] [stderr]    Compiling num-bigint v0.2.2
[INFO] [stderr]     Checking safemem v0.3.2
[INFO] [stderr]     Checking rand_core v0.3.1
[INFO] [stderr]     Checking block-padding v0.1.4
[INFO] [stderr]    Compiling libc v0.2.62
[INFO] [stderr]    Compiling typenum v1.11.2
[INFO] [stderr]     Checking tokio-executor v0.1.8
[INFO] [stderr]     Checking atty v0.2.13
[INFO] [stderr]    Compiling libflate v0.1.27
[INFO] [stderr]     Checking num-integer v0.1.41
[INFO] [stderr]     Checking regex v1.2.1
[INFO] [stderr]     Checking mio-extras v2.0.5
[INFO] [stderr]     Checking hmac v0.7.1
[INFO] [stderr]     Checking rand_xorshift v0.1.1
[INFO] [stderr]     Checking rand_hc v0.1.0
[INFO] [stderr]     Checking rand_isaac v0.1.1
[INFO] [stderr]     Checking rand_chacha v0.1.1
[INFO] [stderr]     Checking clap v2.33.0
[INFO] [stderr]     Checking tokio-current-thread v0.1.6
[INFO] [stderr]     Checking tokio-timer v0.2.11
[INFO] [stderr]     Checking hkdf v0.7.1
[INFO] [stderr]     Checking hkdf v0.8.0
[INFO] [stderr]     Checking rand v0.6.5
[INFO] [stderr]     Checking rand_core v0.5.1
[INFO] [stderr]    Compiling generic-array v0.12.3
[INFO] [stderr]    Compiling xattr v0.2.2
[INFO] [stderr]    Compiling filetime v0.2.7
[INFO] [stderr]     Checking rand_chacha v0.2.1
[INFO] [stderr]     Checking bytes v0.4.12
[INFO] [stderr]     Checking block-buffer v0.7.3
[INFO] [stderr]     Checking base64 v0.9.3
[INFO] [stderr]     Checking base64 v0.10.1
[INFO] [stderr]    Compiling tar v0.4.26
[INFO] [stderr]     Checking rand v0.7.0
[INFO] [stderr]     Checking sha-1 v0.8.1
[INFO] [stderr]     Checking sha2 v0.8.0
[INFO] [stderr]    Compiling digest v0.8.1
[INFO] [stderr]    Compiling openssl-sys v0.9.49
[INFO] [stderr]    Compiling clear_on_drop v0.2.3
[INFO] [stderr]     Checking tokio-io v0.1.12
[INFO] [stderr]     Checking hyper v0.10.16
[INFO] [stderr]     Checking parking_lot_core v0.4.0
[INFO] [stderr]     Checking tokio-threadpool v0.1.15
[INFO] [stderr]     Checking ws v0.9.0
[INFO] [stderr]    Compiling curve25519-dalek v1.2.3
[INFO] [stderr]     Checking tokio-codec v0.1.1
[INFO] [stderr]     Checking parking_lot v0.7.1
[INFO] [stderr]    Compiling libsodium-sys v0.2.2
[INFO] [stderr]    Compiling openssl v0.10.24
[INFO] [stderr]    Compiling native-tls v0.2.3
[INFO] [stderr]     Checking tokio-fs v0.1.6
[INFO] [stderr]     Checking tokio-reactor v0.1.9
[INFO] [stderr]     Checking tokio-tcp v0.1.3
[INFO] [stderr]     Checking tokio-udp v0.1.5
[INFO] [stderr]     Checking tokio-uds v0.2.5
[INFO] [stderr]     Checking tokio v0.1.22
[INFO] [stderr]     Checking tokio-core v0.1.17
[INFO] [stderr]     Checking spake2 v0.2.0
[INFO] [stderr]     Checking tokio-tls v0.2.1
[INFO] [stderr]     Checking websocket v0.23.0
[INFO] [stderr]     Checking sodiumoxide v0.2.2
[INFO] [stderr]     Checking magic-wormhole v0.0.2 (/opt/rustwide/workdir)
[INFO] [stderr]  Documenting magic-wormhole v0.0.2 (/opt/rustwide/workdir)
[INFO] [stdout] error: unused return value of `std::string::String::split_off` that must be used
[INFO] [stdout]   --> src/core/wordlist.rs:42:21
[INFO] [stdout]    |
[INFO] [stdout] 42 |                     suffix.split_off(p as usize);
[INFO] [stdout]    |                     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
[INFO] [stdout]    |
[INFO] [stdout] note: the lint level is defined here
[INFO] [stdout]   --> src/lib.rs:2:9
[INFO] [stdout]    |
[INFO] [stdout] 2  | #![deny(warnings)]
[INFO] [stdout]    |         ^^^^^^^^
[INFO] [stdout]    = note: `#[deny(unused_must_use)]` implied by `#[deny(warnings)]`
[INFO] [stdout]    = note: use `.truncate()` if you don't need the other half
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] error: aborting due to previous error
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stderr] error: could not compile `magic-wormhole`.
[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" "9534a5d02d8a60872267a839fb740c50a2069ca4276e033302feb2981ce973b2", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "9534a5d02d8a60872267a839fb740c50a2069ca4276e033302feb2981ce973b2", kill_on_drop: false }`
[INFO] [stdout] 9534a5d02d8a60872267a839fb740c50a2069ca4276e033302feb2981ce973b2