[INFO] fetching crate back-to-the-future 0.1.7...
[INFO] testing back-to-the-future-0.1.7 against 1.49.0 for beta-1.50-1
[INFO] extracting crate back-to-the-future 0.1.7 into /workspace/builds/worker-0/source
[INFO] validating manifest of crates.io crate back-to-the-future 0.1.7 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 back-to-the-future 0.1.7
[INFO] finished tweaking crates.io crate back-to-the-future 0.1.7
[INFO] tweaked toml for crates.io crate back-to-the-future 0.1.7 written to /workspace/builds/worker-0/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] running `Command { std: "/workspace/cargo-home/bin/cargo" "+1.49.0" "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-0/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-0/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:b8eeb62f26c39b23691079a6cb6de528d8e88b4d71a8f6b1d30f8ba7d9c16de9" "/opt/rustwide/cargo-home/bin/cargo" "+1.49.0" "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] 862a449938711df20a675dab22b4c28f07f041b6e329f1f72e4f708daa0bcf59
[INFO] running `Command { std: "docker" "start" "-a" "862a449938711df20a675dab22b4c28f07f041b6e329f1f72e4f708daa0bcf59", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "inspect" "862a449938711df20a675dab22b4c28f07f041b6e329f1f72e4f708daa0bcf59", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "862a449938711df20a675dab22b4c28f07f041b6e329f1f72e4f708daa0bcf59", kill_on_drop: false }`
[INFO] [stdout] 862a449938711df20a675dab22b4c28f07f041b6e329f1f72e4f708daa0bcf59
[INFO] running `Command { std: "docker" "create" "-v" "/var/lib/crater-agent-workspace/builds/worker-0/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-0/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:b8eeb62f26c39b23691079a6cb6de528d8e88b4d71a8f6b1d30f8ba7d9c16de9" "/opt/rustwide/cargo-home/bin/cargo" "+1.49.0" "build" "--frozen" "--message-format=json", kill_on_drop: false }`
[INFO] [stdout] 3191fefd72cbe1c4c82da7300aec4ff022735c54dd15e68d723a4a57e7cef948
[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" "3191fefd72cbe1c4c82da7300aec4ff022735c54dd15e68d723a4a57e7cef948", kill_on_drop: false }`
[INFO] [stderr]     Blocking waiting for file lock on package cache
[INFO] [stderr]    Compiling back-to-the-future v0.1.7 (/opt/rustwide/workdir)
[INFO] [stdout] error[E0557]: feature has been removed
[INFO] [stdout]   --> src/lib.rs:36:12
[INFO] [stdout]    |
[INFO] [stdout] 36 | #![feature(await_macro)]
[INFO] [stdout]    |            ^^^^^^^^^^^ feature has been removed
[INFO] [stdout]    |
[INFO] [stdout]    = note: subsumed by `.await` syntax
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] error[E0554]: `#![feature]` may not be used on the stable release channel
[INFO] [stdout]   --> src/lib.rs:34:1
[INFO] [stdout]    |
[INFO] [stdout] 34 | #![feature(arbitrary_self_types)]
[INFO] [stdout]    | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] error[E0554]: `#![feature]` may not be used on the stable release channel
[INFO] [stdout]   --> src/lib.rs:35:1
[INFO] [stdout]    |
[INFO] [stdout] 35 | #![feature(async_await)]
[INFO] [stdout]    | ^^^^^^^^^^^^^^^^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] error[E0554]: `#![feature]` may not be used on the stable release channel
[INFO] [stdout]   --> src/lib.rs:36:1
[INFO] [stdout]    |
[INFO] [stdout] 36 | #![feature(await_macro)]
[INFO] [stdout]    | ^^^^^^^^^^^^^^^^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] error[E0554]: `#![feature]` may not be used on the stable release channel
[INFO] [stdout]   --> src/lib.rs:37:1
[INFO] [stdout]    |
[INFO] [stdout] 37 | #![feature(futures_api)]
[INFO] [stdout]    | ^^^^^^^^^^^^^^^^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] error[E0554]: `#![feature]` may not be used on the stable release channel
[INFO] [stdout]   --> src/lib.rs:38:1
[INFO] [stdout]    |
[INFO] [stdout] 38 | #![feature(never_type)]
[INFO] [stdout]    | ^^^^^^^^^^^^^^^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] error[E0554]: `#![feature]` may not be used on the stable release channel
[INFO] [stdout]   --> src/lib.rs:39:1
[INFO] [stdout]    |
[INFO] [stdout] 39 | #![feature(trait_alias)]
[INFO] [stdout]    | ^^^^^^^^^^^^^^^^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] error[E0554]: `#![feature]` may not be used on the stable release channel
[INFO] [stdout]   --> src/lib.rs:40:1
[INFO] [stdout]    |
[INFO] [stdout] 40 | #![feature(specialization)]
[INFO] [stdout]    | ^^^^^^^^^^^^^^^^^^^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: the feature `specialization` is incomplete and may not be safe to use and/or cause compiler crashes
[INFO] [stdout]   --> src/lib.rs:40:12
[INFO] [stdout]    |
[INFO] [stdout] 40 | #![feature(specialization)]
[INFO] [stdout]    |            ^^^^^^^^^^^^^^
[INFO] [stdout]    |
[INFO] [stdout]    = note: `#[warn(incomplete_features)]` on by default
[INFO] [stdout]    = note: see issue #31844 <https://github.com/rust-lang/rust/issues/31844> for more information
[INFO] [stdout]    = help: consider using `min_specialization` instead, which is more stable and complete
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] error: aborting due to 8 previous errors; 1 warning emitted
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] Some errors have detailed explanations: E0554, E0557.
[INFO] [stdout] 
[INFO] [stdout] For more information about an error, try `rustc --explain E0554`.
[INFO] [stdout] 
[INFO] [stderr] error: could not compile `back-to-the-future`
[INFO] [stderr] 
[INFO] [stderr] To learn more, run the command again with --verbose.
[INFO] running `Command { std: "docker" "inspect" "3191fefd72cbe1c4c82da7300aec4ff022735c54dd15e68d723a4a57e7cef948", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "3191fefd72cbe1c4c82da7300aec4ff022735c54dd15e68d723a4a57e7cef948", kill_on_drop: false }`
[INFO] [stdout] 3191fefd72cbe1c4c82da7300aec4ff022735c54dd15e68d723a4a57e7cef948