[INFO] fetching crate algs4 0.7.0...
[INFO] testing algs4-0.7.0 against 1.49.0 for beta-1.50-1
[INFO] extracting crate algs4 0.7.0 into /workspace/builds/worker-3/source
[INFO] validating manifest of crates.io crate algs4 0.7.0 on toolchain 1.49.0
[INFO] running `Command { std: "/workspace/cargo-home/bin/cargo" "+1.49.0" "read-manifest" "--manifest-path" "Cargo.toml", kill_on_drop: false }`
[INFO] started tweaking crates.io crate algs4 0.7.0
[INFO] finished tweaking crates.io crate algs4 0.7.0
[INFO] tweaked toml for crates.io crate algs4 0.7.0 written to /workspace/builds/worker-3/source/Cargo.toml
[INFO] running `Command { std: "/workspace/cargo-home/bin/cargo" "+1.49.0" "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" "+1.49.0" "fetch" "--locked" "--manifest-path" "Cargo.toml", kill_on_drop: false }`
[INFO] [stderr] warning: dependency (sdl2) specified without providing a local path, Git repository, or version to use. This will be considered an error in future versions
[INFO] [stderr] warning: dependency (sdl2_gfx) specified without providing a local path, Git repository, or version to use. This will be considered an error in future versions
[INFO] [stderr] warning: unused manifest key: dev-dependencies.sdl2.sdl2
[INFO] [stderr] warning: unused manifest key: dev-dependencies.sdl2_gfx.sdl2_gfx
[INFO] [stderr]     Blocking waiting for file lock on package cache
[INFO] [stderr]  Downloading crates ...
[INFO] [stderr]   Downloaded c_vec v1.0.12
[INFO] [stderr]   Downloaded sdl2 v0.24.0
[INFO] [stderr]   Downloaded sdl2-sys v0.24.0
[INFO] [stderr]   Downloaded sdl2_gfx v0.24.0
[INFO] [stderr]   Downloaded mtl v0.1.5
[INFO] [stderr]   Downloaded adivon v0.2.6
[INFO] running `Command { std: "docker" "create" "-v" "/var/lib/crater-agent-workspace/builds/worker-3/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-3/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:c8ac004eab7d63a0ad09a2dde3d3353ba464f767bee4de425dc8f74c46a1905e" "/opt/rustwide/cargo-home/bin/cargo" "+1.49.0" "metadata" "--no-deps" "--format-version=1", kill_on_drop: false }`
[INFO] [stdout] 9a13b19f83371cfff5cd2c56cf8212e9dd1d74d1210de4b67c82625279efd74b
[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" "9a13b19f83371cfff5cd2c56cf8212e9dd1d74d1210de4b67c82625279efd74b", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "inspect" "9a13b19f83371cfff5cd2c56cf8212e9dd1d74d1210de4b67c82625279efd74b", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "9a13b19f83371cfff5cd2c56cf8212e9dd1d74d1210de4b67c82625279efd74b", kill_on_drop: false }`
[INFO] [stdout] 9a13b19f83371cfff5cd2c56cf8212e9dd1d74d1210de4b67c82625279efd74b
[INFO] running `Command { std: "docker" "create" "-v" "/var/lib/crater-agent-workspace/builds/worker-3/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-3/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" "rustops/crates-build-env@sha256:c8ac004eab7d63a0ad09a2dde3d3353ba464f767bee4de425dc8f74c46a1905e" "/opt/rustwide/cargo-home/bin/cargo" "+1.49.0" "build" "--frozen" "--message-format=json", kill_on_drop: false }`
[INFO] [stdout] f0c20ab35b213a85f1d1fe2a2589dd813339ea82f14cd4453fb9365776f53fbf
[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" "f0c20ab35b213a85f1d1fe2a2589dd813339ea82f14cd4453fb9365776f53fbf", kill_on_drop: false }`
[INFO] [stderr] warning: dependency (sdl2) specified without providing a local path, Git repository, or version to use. This will be considered an error in future versions
[INFO] [stderr] warning: dependency (sdl2_gfx) specified without providing a local path, Git repository, or version to use. This will be considered an error in future versions
[INFO] [stderr] warning: unused manifest key: dev-dependencies.sdl2.sdl2
[INFO] [stderr] warning: unused manifest key: dev-dependencies.sdl2_gfx.sdl2_gfx
[INFO] [stderr]    Compiling autocfg v1.0.1
[INFO] [stderr]    Compiling libc v0.2.81
[INFO] [stderr]    Compiling rustc-serialize v0.3.24
[INFO] [stderr]    Compiling vec_map v0.6.0
[INFO] [stderr]    Compiling byteorder v0.3.13
[INFO] [stderr]    Compiling num-traits v0.2.14
[INFO] [stderr]    Compiling num-integer v0.1.44
[INFO] [stderr]    Compiling num-iter v0.1.42
[INFO] [stderr]    Compiling rand v0.4.6
[INFO] [stderr]    Compiling rand v0.3.23
[INFO] [stderr]    Compiling adivon v0.2.6
[INFO] [stdout] error[E0554]: `#![feature]` may not be used on the stable release channel
[INFO] [stdout]  --> /opt/rustwide/cargo-home/registry/src/github.com-1ecc6299db9ec823/adivon-0.2.6/src/lib.rs:1:1
[INFO] [stdout]   |
[INFO] [stdout] 1 | #![feature(associated_type_defaults, plugin)]
[INFO] [stdout]   | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stderr]    Compiling num-complex v0.1.43
[INFO] [stderr]    Compiling num-bigint v0.1.44
[INFO] [stdout] error: aborting due to previous error
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] For more information about this error, try `rustc --explain E0554`.
[INFO] [stdout] 
[INFO] [stderr] error: could not compile `adivon`
[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" "f0c20ab35b213a85f1d1fe2a2589dd813339ea82f14cd4453fb9365776f53fbf", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "f0c20ab35b213a85f1d1fe2a2589dd813339ea82f14cd4453fb9365776f53fbf", kill_on_drop: false }`
[INFO] [stdout] f0c20ab35b213a85f1d1fe2a2589dd813339ea82f14cd4453fb9365776f53fbf