[INFO] fetching crate prongs 0.0.5...
[INFO] testing prongs-0.0.5 against beta-2020-07-24 for beta-1.46-1
[INFO] extracting crate prongs 0.0.5 into /workspace/builds/worker-5/source
[INFO] validating manifest of crates.io crate prongs 0.0.5 on toolchain beta-2020-07-24
[INFO] running `Command { std: "/workspace/cargo-home/bin/cargo" "+beta-2020-07-24" "read-manifest" "--manifest-path" "Cargo.toml", kill_on_drop: false }`
[INFO] started tweaking crates.io crate prongs 0.0.5
[INFO] finished tweaking crates.io crate prongs 0.0.5
[INFO] tweaked toml for crates.io crate prongs 0.0.5 written to /workspace/builds/worker-5/source/Cargo.toml
[INFO] running `Command { std: "/workspace/cargo-home/bin/cargo" "+beta-2020-07-24" "generate-lockfile" "--manifest-path" "Cargo.toml" "-Zno-index-update", kill_on_drop: false }`
[INFO] running `Command { std: "/workspace/cargo-home/bin/cargo" "+beta-2020-07-24" "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-5/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-5/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" "MAP_USER_ID=0" "-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" "--network" "none" "rustops/crates-build-env@sha256:a636fd89d022f18117e1dc8fb37a0a009933cdbbe082814857f0e2024962d47c" "/opt/rustwide/cargo-home/bin/cargo" "+beta-2020-07-24" "metadata" "--no-deps" "--format-version=1", kill_on_drop: false }`
[INFO] [stdout] 781633e37d321d854f67b9e69aa374e94b78e541fe724702c8393888fe191464
[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" "781633e37d321d854f67b9e69aa374e94b78e541fe724702c8393888fe191464", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "inspect" "781633e37d321d854f67b9e69aa374e94b78e541fe724702c8393888fe191464", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "781633e37d321d854f67b9e69aa374e94b78e541fe724702c8393888fe191464", kill_on_drop: false }`
[INFO] [stdout] 781633e37d321d854f67b9e69aa374e94b78e541fe724702c8393888fe191464
[INFO] running `Command { std: "docker" "create" "-v" "/var/lib/crater-agent-workspace/builds/worker-5/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-5/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" "MAP_USER_ID=0" "-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" "--network" "none" "rustops/crates-build-env@sha256:a636fd89d022f18117e1dc8fb37a0a009933cdbbe082814857f0e2024962d47c" "/opt/rustwide/cargo-home/bin/cargo" "+beta-2020-07-24" "build" "--frozen" "--message-format=json", kill_on_drop: false }`
[INFO] [stdout] 1b099fb8e7c57fa82d6377c404b065d66f426ac52870164cc61b86625b0bc5bf
[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" "1b099fb8e7c57fa82d6377c404b065d66f426ac52870164cc61b86625b0bc5bf", kill_on_drop: false }`
[INFO] [stderr]    Compiling syn v1.0.38
[INFO] [stderr]    Compiling serde_derive v1.0.114
[INFO] [stderr]    Compiling serde v1.0.114
[INFO] [stderr]    Compiling prongs v0.0.5 (/opt/rustwide/workdir)
[INFO] [stdout] error: No backend selected, use features=<backend> in Cargo.toml or --features <backend> when building directly.
[INFO] [stdout]   --> src/lib.rs:14:1
[INFO] [stdout]    |
[INFO] [stdout] 14 | compile_error!("No backend selected, use features=<backend> in Cargo.toml or --features <backend> when building directly.");
[INFO] [stdout]    | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] error: aborting due to previous error
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stderr] error: could not compile `prongs`.
[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" "1b099fb8e7c57fa82d6377c404b065d66f426ac52870164cc61b86625b0bc5bf", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "1b099fb8e7c57fa82d6377c404b065d66f426ac52870164cc61b86625b0bc5bf", kill_on_drop: false }`
[INFO] [stdout] 1b099fb8e7c57fa82d6377c404b065d66f426ac52870164cc61b86625b0bc5bf