[INFO] fetching crate imdb-async 0.3.3...
[INFO] testing imdb-async-0.3.3 against 1.55.0 for beta-1.56-1
[INFO] extracting crate imdb-async 0.3.3 into /workspace/builds/worker-115/source
[INFO] validating manifest of crates.io crate imdb-async 0.3.3 on toolchain 1.55.0
[INFO] running `Command { std: "/workspace/cargo-home/bin/cargo" "+1.55.0" "metadata" "--manifest-path" "Cargo.toml" "--no-deps", kill_on_drop: false }`
[INFO] started tweaking crates.io crate imdb-async 0.3.3
[INFO] finished tweaking crates.io crate imdb-async 0.3.3
[INFO] tweaked toml for crates.io crate imdb-async 0.3.3 written to /workspace/builds/worker-115/source/Cargo.toml
[INFO] running `Command { std: "/workspace/cargo-home/bin/cargo" "+1.55.0" "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" "+1.55.0" "fetch" "--manifest-path" "Cargo.toml", kill_on_drop: false }`
[INFO] [stderr]     Blocking waiting for file lock on package cache
[INFO] [stderr]     Blocking waiting for file lock on package cache
[INFO] [stderr]  Downloading crates ...
[INFO] [stderr]   Downloaded indexkv v0.2.9
[INFO] [stderr]   Downloaded csv-async v1.2.1
[INFO] running `Command { std: "docker" "create" "-v" "/var/lib/crater-agent-workspace/builds/worker-115/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-115/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:a89201d6b5b9fd45c15d5952ece0a0129e7e80cb26ec023fd59cf09bc26f1604" "/opt/rustwide/cargo-home/bin/cargo" "+1.55.0" "metadata" "--no-deps" "--format-version=1", kill_on_drop: false }`
[INFO] [stdout] a529d7a4cb04b0d95be8a9957b371aeeda98647e27f653c612002485664fd97c
[INFO] running `Command { std: "docker" "start" "-a" "a529d7a4cb04b0d95be8a9957b371aeeda98647e27f653c612002485664fd97c", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "inspect" "a529d7a4cb04b0d95be8a9957b371aeeda98647e27f653c612002485664fd97c", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "a529d7a4cb04b0d95be8a9957b371aeeda98647e27f653c612002485664fd97c", kill_on_drop: false }`
[INFO] [stdout] a529d7a4cb04b0d95be8a9957b371aeeda98647e27f653c612002485664fd97c
[INFO] running `Command { std: "docker" "create" "-v" "/var/lib/crater-agent-workspace/builds/worker-115/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-115/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:a89201d6b5b9fd45c15d5952ece0a0129e7e80cb26ec023fd59cf09bc26f1604" "/opt/rustwide/cargo-home/bin/cargo" "+1.55.0" "build" "--frozen" "--message-format=json", kill_on_drop: false }`
[INFO] [stdout] c1a9ace55d94a4d97123afbfec25e867538f78e4a4980cdb49f0dd962143fd95
[INFO] running `Command { std: "docker" "start" "-a" "c1a9ace55d94a4d97123afbfec25e867538f78e4a4980cdb49f0dd962143fd95", kill_on_drop: false }`
[INFO] [stderr]    Compiling libc v0.2.101
[INFO] [stderr]    Compiling futures-sink v0.3.17
[INFO] [stderr]    Compiling futures-channel v0.3.17
[INFO] [stderr]    Compiling futures-io v0.3.17
[INFO] [stderr]    Compiling serde v1.0.130
[INFO] [stderr]    Compiling bytes v0.5.6
[INFO] [stderr]    Compiling pin-project-lite v0.1.12
[INFO] [stderr]    Compiling once_cell v1.8.0
[INFO] [stderr]    Compiling spin v0.5.2
[INFO] [stderr]    Compiling untrusted v0.7.1
[INFO] [stderr]    Compiling bytes v1.1.0
[INFO] [stderr]    Compiling ident_case v1.0.1
[INFO] [stderr]    Compiling tower-service v0.3.1
[INFO] [stderr]    Compiling parking_lot_core v0.8.5
[INFO] [stderr]    Compiling httpdate v0.3.2
[INFO] [stderr]    Compiling regex-automata v0.1.10
[INFO] [stderr]    Compiling smallvec v1.6.1
[INFO] [stderr]    Compiling ipnet v2.3.1
[INFO] [stderr]    Compiling futures-util v0.3.17
[INFO] [stderr]    Compiling ring v0.16.20
[INFO] [stderr]    Compiling tracing-core v0.1.19
[INFO] [stderr]    Compiling rustversion v1.0.5
[INFO] [stderr]    Compiling instant v0.1.10
[INFO] [stderr]    Compiling lock_api v0.4.5
[INFO] [stderr]    Compiling syn v1.0.76
[INFO] [stderr]    Compiling want v0.3.0
[INFO] [stderr]    Compiling csv-core v0.1.10
[INFO] [stderr]    Compiling tracing v0.1.26
[INFO] [stderr]    Compiling http v0.2.4
[INFO] [stderr]    Compiling net2 v0.2.37
[INFO] [stderr]    Compiling iovec v0.1.4
[INFO] [stderr]    Compiling socket2 v0.3.19
[INFO] [stderr]    Compiling flate2 v1.0.21
[INFO] [stderr]    Compiling parking_lot v0.11.2
[INFO] [stderr]    Compiling mio v0.6.23
[INFO] [stderr]    Compiling async-compression v0.3.8
[INFO] [stderr]    Compiling http-body v0.3.1
[INFO] [stderr]    Compiling darling_core v0.13.0
[INFO] [stderr]    Compiling webpki v0.21.4
[INFO] [stderr]    Compiling sct v0.6.1
[INFO] [stderr]    Compiling rustls v0.18.1
[INFO] [stderr]    Compiling webpki-roots v0.20.0
[INFO] [stderr]    Compiling serde_derive v1.0.130
[INFO] [stderr]    Compiling futures-macro v0.3.17
[INFO] [stderr]    Compiling tokio-macros v0.2.6
[INFO] [stderr]    Compiling pin-project-internal v1.0.8
[INFO] [stderr]    Compiling thiserror-impl v1.0.29
[INFO] [stderr]    Compiling strum_macros v0.20.1
[INFO] [stderr]    Compiling serde_repr v0.1.7
[INFO] [stderr]    Compiling darling_macro v0.13.0
[INFO] [stderr]    Compiling tokio v0.2.25
[INFO] [stderr]    Compiling darling v0.13.0
[INFO] [stderr]    Compiling serde_with_macros v1.5.0
[INFO] [stderr]    Compiling pin-project v1.0.8
[INFO] [stderr]    Compiling tracing-futures v0.2.5
[INFO] [stderr]    Compiling thiserror v1.0.29
[INFO] [stderr]    Compiling strum v0.20.0
[INFO] [stderr]    Compiling tokio-util v0.3.1
[INFO] [stderr]    Compiling tokio-rustls v0.14.1
[INFO] [stderr]    Compiling h2 v0.2.7
[INFO] [stderr]    Compiling futures-executor v0.3.17
[INFO] [stderr]    Compiling futures v0.3.17
[INFO] [stderr]    Compiling bincode v1.3.3
[INFO] [stderr]    Compiling bstr v0.2.16
[INFO] [stderr]    Compiling serde_urlencoded v0.7.0
[INFO] [stderr]    Compiling serde_with v1.10.0
[INFO] [stderr]    Compiling async-bincode v0.5.1
[INFO] [stderr]    Compiling csv-async v1.2.1
[INFO] [stderr]    Compiling indexkv v0.2.9
[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/indexkv-0.2.9/src/lib.rs:1:1
[INFO] [stdout]   |
[INFO] [stdout] 1 | #![feature(const_fn_trait_bound)]
[INFO] [stdout]   | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stderr]    Compiling hyper v0.13.10
[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 `indexkv` due to 2 previous errors
[INFO] [stderr] warning: build failed, waiting for other jobs to finish...
[INFO] [stderr] error: build failed
[INFO] running `Command { std: "docker" "inspect" "c1a9ace55d94a4d97123afbfec25e867538f78e4a4980cdb49f0dd962143fd95", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "c1a9ace55d94a4d97123afbfec25e867538f78e4a4980cdb49f0dd962143fd95", kill_on_drop: false }`
[INFO] [stdout] c1a9ace55d94a4d97123afbfec25e867538f78e4a4980cdb49f0dd962143fd95