[INFO] fetching crate memdb 1.0.0...
[INFO] testing memdb-1.0.0 against 1.91.0 for beta-1.92-2
[INFO] extracting crate memdb 1.0.0 into /workspace/builds/worker-6-tc1/source
[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-6-tc1/source/Cargo.toml
[INFO] validating manifest of crates.io crate memdb 1.0.0 on toolchain 1.91.0
[INFO] running `Command { std: CARGO_HOME="/workspace/cargo-home" RUSTUP_HOME="/workspace/rustup-home" "/workspace/cargo-home/bin/cargo" "+1.91.0" "metadata" "--manifest-path" "Cargo.toml" "--no-deps", kill_on_drop: false }`
[INFO] running `Command { std: CARGO_HOME="/workspace/cargo-home" RUSTUP_HOME="/workspace/rustup-home" "/workspace/cargo-home/bin/cargo" "+1.91.0" "generate-lockfile" "--manifest-path" "Cargo.toml", kill_on_drop: false }`
[INFO] [stderr]     Updating crates.io index
[INFO] [stderr]     Blocking waiting for file lock on package cache
[INFO] [stderr]      Locking 89 packages to latest compatible versions
[INFO] [stderr]       Adding parking_lot v0.6.4 (available: v0.12.5)
[INFO] running `Command { std: CARGO_HOME="/workspace/cargo-home" RUSTUP_HOME="/workspace/rustup-home" "/workspace/cargo-home/bin/cargo" "+1.91.0" "fetch" "--manifest-path" "Cargo.toml", kill_on_drop: false }`
[INFO] [stderr]     Blocking waiting for file lock on package cache
[INFO] [stderr]  Downloading crates ...
[INFO] [stderr]   Downloaded futures-io-preview v0.3.0-alpha.19
[INFO] [stderr]   Downloaded futures-core-preview v0.3.0-alpha.19
[INFO] [stderr]   Downloaded runtime-native v0.3.0-alpha.6
[INFO] [stderr]   Downloaded async-datagram v3.0.0
[INFO] [stderr]   Downloaded futures-channel-preview v0.3.0-alpha.19
[INFO] [stderr]   Downloaded futures-util-preview v0.3.0-alpha.19
[INFO] [stderr]   Downloaded owning_ref v0.4.1
[INFO] [stderr]   Downloaded parking_lot_core v0.6.3
[INFO] [stderr]   Downloaded romio v0.3.0-alpha.10
[INFO] [stderr]   Downloaded wasm-bindgen-futures v0.3.27
[INFO] [stderr]   Downloaded futures-sink-preview v0.3.0-alpha.19
[INFO] [stderr]   Downloaded lock_api v0.1.5
[INFO] [stderr]   Downloaded runtime-attributes v0.3.0-alpha.6
[INFO] [stderr]   Downloaded futures-timer v0.3.0
[INFO] [stderr]   Downloaded crossbeam-queue v0.2.3
[INFO] [stderr]   Downloaded crossbeam v0.7.3
[INFO] [stderr]   Downloaded juliex v0.3.0-alpha.8
[INFO] [stderr]   Downloaded smallvec v0.6.14
[INFO] [stderr]   Downloaded futures-executor-preview v0.3.0-alpha.19
[INFO] [stderr]   Downloaded runtime-raw v0.3.0-alpha.5
[INFO] [stderr]   Downloaded runtime v0.3.0-alpha.8
[INFO] [stderr]   Downloaded async-ready v3.0.0
[INFO] [stderr]   Downloaded futures-preview v0.3.0-alpha.19
[INFO] running `Command { std: "docker" "create" "-v" "/var/lib/crater-agent-workspace/builds/worker-6-tc1/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-6-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@sha256:4848fb76d95f26979359cc7e45710b1dbc8f3acb7aeedee7c460d7702230f228" "/opt/rustwide/cargo-home/bin/cargo" "+1.91.0" "metadata" "--no-deps" "--format-version=1", kill_on_drop: false }`
[INFO] [stdout] 39432c283b151c93bb3208a8c10afefe7808563bcf19157796204e71089a5af2
[INFO] running `Command { std: "docker" "start" "-a" "39432c283b151c93bb3208a8c10afefe7808563bcf19157796204e71089a5af2", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "inspect" "39432c283b151c93bb3208a8c10afefe7808563bcf19157796204e71089a5af2", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "39432c283b151c93bb3208a8c10afefe7808563bcf19157796204e71089a5af2", kill_on_drop: false }`
[INFO] [stdout] 39432c283b151c93bb3208a8c10afefe7808563bcf19157796204e71089a5af2
[INFO] running `Command { std: "docker" "create" "-v" "/var/lib/crater-agent-workspace/builds/worker-6-tc1/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-6-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=warn" "-e" "RUSTDOCFLAGS=--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@sha256:4848fb76d95f26979359cc7e45710b1dbc8f3acb7aeedee7c460d7702230f228" "/opt/rustwide/cargo-home/bin/cargo" "+1.91.0" "build" "--frozen" "--message-format=json", kill_on_drop: false }`
[INFO] [stdout] 4d7ad319d8abde56dcee430bc1bd2ff3d6a2565ef2804d6e504a88b074b6587c
[INFO] running `Command { std: "docker" "start" "-a" "4d7ad319d8abde56dcee430bc1bd2ff3d6a2565ef2804d6e504a88b074b6587c", kill_on_drop: false }`
[INFO] [stderr]    Compiling semver-parser v0.7.0
[INFO] [stderr]    Compiling maybe-uninit v2.0.0
[INFO] [stderr]    Compiling rand_core v0.4.2
[INFO] [stderr]    Compiling stable_deref_trait v1.2.1
[INFO] [stderr]    Compiling scopeguard v0.3.3
[INFO] [stderr]    Compiling owning_ref v0.4.1
[INFO] [stderr]    Compiling rand_core v0.3.1
[INFO] [stderr]    Compiling lock_api v0.1.5
[INFO] [stderr]    Compiling rand v0.5.6
[INFO] [stderr]    Compiling semver v0.9.0
[INFO] [stderr]    Compiling smallvec v0.6.14
[INFO] [stderr]    Compiling rustc_version v0.2.3
[INFO] [stderr]    Compiling parking_lot_core v0.3.1
[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: the feature `async_await` has been stable since 1.39.0 and no longer requires an attribute to enable
[INFO] [stdout]  --> src/lib.rs:1:12
[INFO] [stdout]   |
[INFO] [stdout] 1 | #![feature(async_await)]
[INFO] [stdout]   |            ^^^^^^^^^^^
[INFO] [stdout]   |
[INFO] [stdout]   = note: `#[warn(stable_features)]` on by default
[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` (lib) due to 1 previous error; 1 warning emitted
[INFO] running `Command { std: "docker" "inspect" "4d7ad319d8abde56dcee430bc1bd2ff3d6a2565ef2804d6e504a88b074b6587c", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "4d7ad319d8abde56dcee430bc1bd2ff3d6a2565ef2804d6e504a88b074b6587c", kill_on_drop: false }`
[INFO] [stdout] 4d7ad319d8abde56dcee430bc1bd2ff3d6a2565ef2804d6e504a88b074b6587c