[INFO] fetching crate memdb 1.0.0...
[INFO] testing memdb-1.0.0 against 1.60.0 for beta-1.61-1
[INFO] extracting crate memdb 1.0.0 into /workspace/builds/worker-4/source
[INFO] validating manifest of crates.io crate memdb 1.0.0 on toolchain 1.60.0
[INFO] running `Command { std: "/workspace/cargo-home/bin/cargo" "+1.60.0" "metadata" "--manifest-path" "Cargo.toml" "--no-deps", kill_on_drop: false }`
[INFO] started tweaking crates.io crate memdb 1.0.0
[INFO] finished tweaking crates.io crate memdb 1.0.0
[INFO] tweaked toml for crates.io crate memdb 1.0.0 written to /workspace/builds/worker-4/source/Cargo.toml
[INFO] running `Command { std: "/workspace/cargo-home/bin/cargo" "+1.60.0" "generate-lockfile" "--manifest-path" "Cargo.toml" "-Zno-index-update", kill_on_drop: false }`
[INFO] running `Command { std: "/workspace/cargo-home/bin/cargo" "+1.60.0" "fetch" "--manifest-path" "Cargo.toml", kill_on_drop: false }`
[INFO] [stderr]  Downloading crates ...
[INFO] [stderr]   Downloaded futures-preview v0.3.0-alpha.19
[INFO] [stderr]   Downloaded parking_lot v0.6.4
[INFO] [stderr]   Downloaded parking_lot_core v0.3.1
[INFO] [stderr]   Downloaded lock_api v0.1.5
[INFO] [stderr]   Downloaded runtime-attributes v0.3.0-alpha.6
[INFO] [stderr]   Downloaded pin-project-internal v0.4.29
[INFO] [stderr]   Downloaded pin-project v0.4.29
[INFO] [stderr]   Downloaded async-datagram v3.0.0
[INFO] [stderr]   Downloaded romio v0.3.0-alpha.10
[INFO] [stderr]   Downloaded async-ready v3.0.0
[INFO] [stderr]   Downloaded runtime-native v0.3.0-alpha.6
[INFO] [stderr]   Downloaded futures-io-preview v0.3.0-alpha.19
[INFO] [stderr]   Downloaded futures-sink-preview v0.3.0-alpha.19
[INFO] [stderr]   Downloaded runtime-raw v0.3.0-alpha.5
[INFO] [stderr]   Downloaded juliex v0.3.0-alpha.8
[INFO] [stderr]   Downloaded runtime v0.3.0-alpha.8
[INFO] [stderr]   Downloaded futures-timer v0.3.0
[INFO] running `Command { std: "docker" "create" "-v" "/var/lib/crater-agent-workspace/builds/worker-4/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-4/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:eaef2f80f755933c374d2ae5edccceec0c1312ceb8a4e0b6404e8ab76561e1e5" "/opt/rustwide/cargo-home/bin/cargo" "+1.60.0" "metadata" "--no-deps" "--format-version=1", kill_on_drop: false }`
[INFO] [stdout] 333cee3cc1d89a3a4ef820dd8f1ee32158898366fe0217b30f8bd272dfb21c26
[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" "333cee3cc1d89a3a4ef820dd8f1ee32158898366fe0217b30f8bd272dfb21c26", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "inspect" "333cee3cc1d89a3a4ef820dd8f1ee32158898366fe0217b30f8bd272dfb21c26", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "333cee3cc1d89a3a4ef820dd8f1ee32158898366fe0217b30f8bd272dfb21c26", kill_on_drop: false }`
[INFO] [stdout] 333cee3cc1d89a3a4ef820dd8f1ee32158898366fe0217b30f8bd272dfb21c26
[INFO] running `Command { std: "docker" "create" "-v" "/var/lib/crater-agent-workspace/builds/worker-4/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-4/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" "ghcr.io/rust-lang/crates-build-env/linux@sha256:eaef2f80f755933c374d2ae5edccceec0c1312ceb8a4e0b6404e8ab76561e1e5" "/opt/rustwide/cargo-home/bin/cargo" "+1.60.0" "build" "--frozen" "--message-format=json", kill_on_drop: false }`
[INFO] [stdout] 9388ffb7ac99bcd1e35517ec9bdeea332ffc0e9e8b17328e2bde98ad3f735d00
[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" "9388ffb7ac99bcd1e35517ec9bdeea332ffc0e9e8b17328e2bde98ad3f735d00", kill_on_drop: false }`
[INFO] [stderr]    Compiling parking_lot_core v0.3.1
[INFO] [stderr]    Compiling rand v0.5.6
[INFO] [stderr]    Compiling lock_api v0.1.5
[INFO] [stderr]    Compiling parking_lot v0.6.4
[INFO] [stderr]    Compiling memdb v1.0.0 (/opt/rustwide/workdir)
[INFO] [stdout] error[E0554]: `#![feature]` may not be used on the stable release channel
[INFO] [stdout]  --> src/lib.rs:1:1
[INFO] [stdout]   |
[INFO] [stdout] 1 | #![feature(async_await)]
[INFO] [stdout]   | ^^^^^^^^^^^^^^^^^^^^^^^^ help: remove the attribute
[INFO] [stdout]   |
[INFO] [stdout]   = help: the feature `async_await` has been stable since 1.39.0 and no longer requires an attribute to enable
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: `must_use` attribute on `async` functions applies to the anonymous `Future` returned by the function, not the value within
[INFO] [stdout]   --> src/lib.rs:54:5
[INFO] [stdout]    |
[INFO] [stdout] 54 |       #[must_use]
[INFO] [stdout]    |       ^^^^^^^^^^^
[INFO] [stdout] 55 |       #[inline]
[INFO] [stdout] 56 | /     pub async fn get(&self, key: impl AsRef<[u8]>) -> io::Result<Option<Vec<u8>>> {
[INFO] [stdout] 57 | |         let key = key.as_ref().to_owned();
[INFO] [stdout] 58 | |         let hashmap = &self.hashmap.read();
[INFO] [stdout] 59 | |         Ok(hashmap.get(&key).cloned())
[INFO] [stdout] 60 | |     }
[INFO] [stdout]    | |_____- this attribute does nothing, the `Future`s returned by async functions are already `must_use`
[INFO] [stdout]    |
[INFO] [stdout]    = note: `#[warn(unused_attributes)]` on by default
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] error: aborting due to previous error; 1 warning emitted
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] For more information about this error, try `rustc --explain E0554`.
[INFO] [stdout] 
[INFO] [stderr] error: could not compile `memdb` due to 2 previous errors; 1 warning emitted
[INFO] running `Command { std: "docker" "inspect" "9388ffb7ac99bcd1e35517ec9bdeea332ffc0e9e8b17328e2bde98ad3f735d00", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "9388ffb7ac99bcd1e35517ec9bdeea332ffc0e9e8b17328e2bde98ad3f735d00", kill_on_drop: false }`
[INFO] [stdout] 9388ffb7ac99bcd1e35517ec9bdeea332ffc0e9e8b17328e2bde98ad3f735d00