[INFO] fetching crate monotron-synth 0.2.0...
[INFO] checking monotron-synth-0.2.0 against master#0a8629bff642c3c3b84bb644c0099194f063b627 for pr-86231
[INFO] extracting crate monotron-synth 0.2.0 into /workspace/builds/worker-14/source
[INFO] validating manifest of crates.io crate monotron-synth 0.2.0 on toolchain 0a8629bff642c3c3b84bb644c0099194f063b627
[INFO] running `Command { std: "/workspace/cargo-home/bin/cargo" "+0a8629bff642c3c3b84bb644c0099194f063b627" "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-14/source/Cargo.toml
[INFO] running `Command { std: "/workspace/cargo-home/bin/cargo" "+0a8629bff642c3c3b84bb644c0099194f063b627" "generate-lockfile" "--manifest-path" "Cargo.toml" "-Zno-index-update", kill_on_drop: false }`
[INFO] running `Command { std: "/workspace/cargo-home/bin/cargo" "+0a8629bff642c3c3b84bb644c0099194f063b627" "fetch" "--manifest-path" "Cargo.toml", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "create" "-v" "/var/lib/crater-agent-workspace/builds/worker-14/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-14/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@sha256:20528e8c29e4536546f0102ce88568b16ea7538393a33fcca951030f7af10457" "/opt/rustwide/cargo-home/bin/cargo" "+0a8629bff642c3c3b84bb644c0099194f063b627" "metadata" "--no-deps" "--format-version=1", kill_on_drop: false }`
[INFO] [stdout] 95aae5f487b6b088b6b6d39f907629c9f7cae2c2426f9aacc687a24ae30dccda
[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" "95aae5f487b6b088b6b6d39f907629c9f7cae2c2426f9aacc687a24ae30dccda", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "inspect" "95aae5f487b6b088b6b6d39f907629c9f7cae2c2426f9aacc687a24ae30dccda", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "95aae5f487b6b088b6b6d39f907629c9f7cae2c2426f9aacc687a24ae30dccda", kill_on_drop: false }`
[INFO] [stdout] 95aae5f487b6b088b6b6d39f907629c9f7cae2c2426f9aacc687a24ae30dccda
[INFO] running `Command { std: "docker" "create" "-v" "/var/lib/crater-agent-workspace/builds/worker-14/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-14/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@sha256:20528e8c29e4536546f0102ce88568b16ea7538393a33fcca951030f7af10457" "/opt/rustwide/cargo-home/bin/cargo" "+0a8629bff642c3c3b84bb644c0099194f063b627" "check" "--frozen" "--all" "--all-targets" "--message-format=json", kill_on_drop: false }`
[INFO] [stdout] 063494f4a5dfdd854109c08eceb7ca803f3ce2934a19a70fdb8a68d49a5115ca
[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" "063494f4a5dfdd854109c08eceb7ca803f3ce2934a19a70fdb8a68d49a5115ca", kill_on_drop: false }`
[INFO] [stderr]    Compiling proc-macro2 v1.0.27
[INFO] [stderr]    Compiling pkg-config v0.3.19
[INFO] [stderr]    Compiling unicode-xid v0.2.2
[INFO] [stderr]    Compiling autocfg v1.0.1
[INFO] [stderr]    Compiling syn v1.0.73
[INFO] [stderr]    Compiling libc v0.2.97
[INFO] [stderr]    Compiling bitflags v1.2.1
[INFO] [stderr]     Checking monotron-synth v0.2.0 (/opt/rustwide/workdir)
[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]     |         ^^^^^^^^^^^^^^^^^^^^ help: remove these parentheses
[INFO] [stdout]     |
[INFO] [stdout]     = note: `#[warn(unused_parens)]` 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 E0557`.
[INFO] [stdout] 
[INFO] [stderr] error: could not compile `monotron-synth`
[INFO] [stderr] 
[INFO] [stderr] To learn more, run the command again with --verbose.
[INFO] [stderr] warning: build failed, waiting for other jobs to finish...
[INFO] [stderr] error: build failed
[INFO] running `Command { std: "docker" "inspect" "063494f4a5dfdd854109c08eceb7ca803f3ce2934a19a70fdb8a68d49a5115ca", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "063494f4a5dfdd854109c08eceb7ca803f3ce2934a19a70fdb8a68d49a5115ca", kill_on_drop: false }`
[INFO] [stdout] 063494f4a5dfdd854109c08eceb7ca803f3ce2934a19a70fdb8a68d49a5115ca