[INFO] fetching crate back-to-the-future 0.1.7...
[INFO] checking back-to-the-future-0.1.7 against master#80399064afa4a2cd153f30d02c25f7ea0383ed65 for opaque-soundness-fix
[INFO] extracting crate back-to-the-future 0.1.7 into /workspace/builds/worker-5-tc1/source
[INFO] validating manifest of crates.io crate back-to-the-future 0.1.7 on toolchain 80399064afa4a2cd153f30d02c25f7ea0383ed65
[INFO] running `Command { std: CARGO_HOME="/workspace/cargo-home" RUSTUP_HOME="/workspace/rustup-home" "/workspace/cargo-home/bin/cargo" "+80399064afa4a2cd153f30d02c25f7ea0383ed65" "metadata" "--manifest-path" "Cargo.toml" "--no-deps", 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-5-tc1/source/Cargo.toml
[INFO] running `Command { std: CARGO_HOME="/workspace/cargo-home" RUSTUP_HOME="/workspace/rustup-home" "/workspace/cargo-home/bin/cargo" "+80399064afa4a2cd153f30d02c25f7ea0383ed65" "generate-lockfile" "--manifest-path" "Cargo.toml", kill_on_drop: false }`
[INFO] [stderr]     Updating crates.io index
[INFO] running `Command { std: CARGO_HOME="/workspace/cargo-home" RUSTUP_HOME="/workspace/rustup-home" "/workspace/cargo-home/bin/cargo" "+80399064afa4a2cd153f30d02c25f7ea0383ed65" "fetch" "--manifest-path" "Cargo.toml", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "create" "-v" "/var/lib/crater-agent-workspace/builds/worker-5-tc1/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-5-tc1/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" "ghcr.io/rust-lang/crates-build-env/linux@sha256:2788e3201cd34a07e3172128adcd8b3090168a8e3bcc40d7c032b9dda1df7d1c" "/opt/rustwide/cargo-home/bin/cargo" "+80399064afa4a2cd153f30d02c25f7ea0383ed65" "metadata" "--no-deps" "--format-version=1", kill_on_drop: false }`
[INFO] [stdout] aec377d59341533e8fb4ebba4f629bcba44b0463b8754a559a90b9e66f7d9889
[INFO] running `Command { std: "docker" "start" "-a" "aec377d59341533e8fb4ebba4f629bcba44b0463b8754a559a90b9e66f7d9889", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "inspect" "aec377d59341533e8fb4ebba4f629bcba44b0463b8754a559a90b9e66f7d9889", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "aec377d59341533e8fb4ebba4f629bcba44b0463b8754a559a90b9e66f7d9889", kill_on_drop: false }`
[INFO] [stdout] aec377d59341533e8fb4ebba4f629bcba44b0463b8754a559a90b9e66f7d9889
[INFO] running `Command { std: "docker" "create" "-v" "/var/lib/crater-agent-workspace/builds/worker-5-tc1/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-5-tc1/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" "RUSTDOCFLAGS=--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" "ghcr.io/rust-lang/crates-build-env/linux@sha256:2788e3201cd34a07e3172128adcd8b3090168a8e3bcc40d7c032b9dda1df7d1c" "/opt/rustwide/cargo-home/bin/cargo" "+80399064afa4a2cd153f30d02c25f7ea0383ed65" "check" "--frozen" "--all" "--all-targets" "--message-format=json", kill_on_drop: false }`
[INFO] [stdout] 13bc5560f6a8ea2accf34f768d4ba65d6a2970447f413d532afcfdd94eacb195
[INFO] running `Command { std: "docker" "start" "-a" "13bc5560f6a8ea2accf34f768d4ba65d6a2970447f413d532afcfdd94eacb195", kill_on_drop: false }`
[INFO] [stderr]     Checking back-to-the-future v0.1.7 (/opt/rustwide/workdir)
[INFO] [stderr]     Checking iovec v0.1.4
[INFO] [stderr]     Checking net2 v0.2.39
[INFO] [stderr]     Checking parking_lot_core v0.6.3
[INFO] [stderr]     Checking tokio-threadpool v0.1.18
[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] 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: 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]    = note: `#[warn(incomplete_features)]` on by default
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: the feature `async_await` has been stable since 1.39.0 and no longer requires an attribute to enable
[INFO] [stdout]   --> src/lib.rs:35:12
[INFO] [stdout]    |
[INFO] [stdout] 35 | #![feature(async_await)]
[INFO] [stdout]    |            ^^^^^^^^^^^
[INFO] [stdout]    |
[INFO] [stdout]    = note: `#[warn(stable_features)]` on by default
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: the feature `futures_api` has been stable since 1.36.0 and no longer requires an attribute to enable
[INFO] [stdout]   --> src/lib.rs:37:12
[INFO] [stdout]    |
[INFO] [stdout] 37 | #![feature(futures_api)]
[INFO] [stdout]    |            ^^^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] error: aborting due to 1 previous error; 3 warnings emitted
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] For more information about this error, try `rustc --explain E0557`.
[INFO] [stdout] 
[INFO] [stderr] error: could not compile `back-to-the-future` (lib) due to 2 previous errors; 3 warnings emitted
[INFO] [stderr] warning: build failed, waiting for other jobs to finish...
[INFO] running `Command { std: "docker" "inspect" "13bc5560f6a8ea2accf34f768d4ba65d6a2970447f413d532afcfdd94eacb195", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "13bc5560f6a8ea2accf34f768d4ba65d6a2970447f413d532afcfdd94eacb195", kill_on_drop: false }`
[INFO] [stdout] 13bc5560f6a8ea2accf34f768d4ba65d6a2970447f413d532afcfdd94eacb195
