[INFO] fetching crate monotron-synth 0.2.0...
[INFO] checking monotron-synth-0.2.0 against master#936f2600b6c903b04387f74ed5cbce88bb06d243 for pr-91141
[INFO] extracting crate monotron-synth 0.2.0 into /workspace/builds/worker-57/source
[INFO] validating manifest of crates.io crate monotron-synth 0.2.0 on toolchain 936f2600b6c903b04387f74ed5cbce88bb06d243
[INFO] running `Command { std: "/workspace/cargo-home/bin/cargo" "+936f2600b6c903b04387f74ed5cbce88bb06d243" "metadata" "--manifest-path" "Cargo.toml" "--no-deps", kill_on_drop: false }`
[INFO] started tweaking crates.io crate monotron-synth 0.2.0
[INFO] finished tweaking crates.io crate monotron-synth 0.2.0
[INFO] tweaked toml for crates.io crate monotron-synth 0.2.0 written to /workspace/builds/worker-57/source/Cargo.toml
[INFO] running `Command { std: "/workspace/cargo-home/bin/cargo" "+936f2600b6c903b04387f74ed5cbce88bb06d243" "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" "+936f2600b6c903b04387f74ed5cbce88bb06d243" "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 libpulse-simple-sys v1.19.1
[INFO] [stderr]   Downloaded libpulse-sys v1.19.2
[INFO] [stderr]   Downloaded libpulse-binding v2.25.0
[INFO] [stderr]   Downloaded libpulse-simple-binding v2.24.1
[INFO] running `Command { std: "docker" "create" "-v" "/var/lib/crater-agent-workspace/builds/worker-57/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-57/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@sha256:5736fa189c1c60b01babf4b8b698fe57b6ecc41933a7ff2e0b8d7a221459412b" "/opt/rustwide/cargo-home/bin/cargo" "+936f2600b6c903b04387f74ed5cbce88bb06d243" "metadata" "--no-deps" "--format-version=1", kill_on_drop: false }`
[INFO] [stdout] 37ab23b53ed4e7cb80837adb6e6f42e2b2b34181bf2c725f3a57467f4475a60c
[INFO] running `Command { std: "docker" "start" "-a" "37ab23b53ed4e7cb80837adb6e6f42e2b2b34181bf2c725f3a57467f4475a60c", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "inspect" "37ab23b53ed4e7cb80837adb6e6f42e2b2b34181bf2c725f3a57467f4475a60c", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "37ab23b53ed4e7cb80837adb6e6f42e2b2b34181bf2c725f3a57467f4475a60c", kill_on_drop: false }`
[INFO] [stdout] 37ab23b53ed4e7cb80837adb6e6f42e2b2b34181bf2c725f3a57467f4475a60c
[INFO] running `Command { std: "docker" "create" "-v" "/var/lib/crater-agent-workspace/builds/worker-57/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-57/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" "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@sha256:5736fa189c1c60b01babf4b8b698fe57b6ecc41933a7ff2e0b8d7a221459412b" "/opt/rustwide/cargo-home/bin/cargo" "+936f2600b6c903b04387f74ed5cbce88bb06d243" "check" "--frozen" "--all" "--all-targets" "--message-format=json", kill_on_drop: false }`
[INFO] [stdout] 6a10939474db4fc6cb5e8c14d2bae2e64de48aa0eb4e882da04cbe9d051bd1b9
[INFO] running `Command { std: "docker" "start" "-a" "6a10939474db4fc6cb5e8c14d2bae2e64de48aa0eb4e882da04cbe9d051bd1b9", kill_on_drop: false }`
[INFO] [stderr]     Blocking waiting for file lock on package cache
[INFO] [stderr]    Compiling proc-macro2 v1.0.32
[INFO] [stderr]    Compiling pkg-config v0.3.22
[INFO] [stderr]    Compiling unicode-xid v0.2.2
[INFO] [stderr]    Compiling libc v0.2.108
[INFO] [stderr]     Checking monotron-synth v0.2.0 (/opt/rustwide/workdir)
[INFO] [stderr]    Compiling num-traits v0.2.14
[INFO] [stdout] error[E0557]: feature has been removed
[INFO] [stdout]  --> src/lib.rs:2:12
[INFO] [stdout]   |
[INFO] [stdout] 2 | #![feature(const_fn)]
[INFO] [stdout]   |            ^^^^^^^^ feature has been removed
[INFO] [stdout]   |
[INFO] [stdout]   = note: split into finer-grained feature gates
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unnecessary parentheses around block return value
[INFO] [stdout]    --> src/lib.rs:359:9
[INFO] [stdout]     |
[INFO] [stdout] 359 |         (intermediate as u8)
[INFO] [stdout]     |         ^                  ^
[INFO] [stdout]     |
[INFO] [stdout]     = note: `#[warn(unused_parens)]` on by default
[INFO] [stdout] help: remove these parentheses
[INFO] [stdout]     |
[INFO] [stdout] 359 -         (intermediate as u8)
[INFO] [stdout] 359 +         intermediate as u8
[INFO] [stdout]     | 
[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 E0557`.
[INFO] [stdout] 
[INFO] [stderr] error: could not compile `monotron-synth` due to 2 previous errors; 1 warning emitted
[INFO] [stderr] warning: build failed, waiting for other jobs to finish...
[INFO] [stderr] error: build failed
[INFO] running `Command { std: "docker" "inspect" "6a10939474db4fc6cb5e8c14d2bae2e64de48aa0eb4e882da04cbe9d051bd1b9", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "6a10939474db4fc6cb5e8c14d2bae2e64de48aa0eb4e882da04cbe9d051bd1b9", kill_on_drop: false }`
[INFO] [stdout] 6a10939474db4fc6cb5e8c14d2bae2e64de48aa0eb4e882da04cbe9d051bd1b9