[INFO] fetching crate lark-unify 0.1.0...
[INFO] checking lark-unify-0.1.0 against try#8b72f65b805cbe4c261de45030d663f524f27376 for pr-78991
[INFO] extracting crate lark-unify 0.1.0 into /workspace/builds/worker-5/source
[INFO] validating manifest of crates.io crate lark-unify 0.1.0 on toolchain 8b72f65b805cbe4c261de45030d663f524f27376
[INFO] running `Command { std: "/workspace/cargo-home/bin/cargo" "+8b72f65b805cbe4c261de45030d663f524f27376" "read-manifest" "--manifest-path" "Cargo.toml", kill_on_drop: false }`
[INFO] started tweaking crates.io crate lark-unify 0.1.0
[INFO] finished tweaking crates.io crate lark-unify 0.1.0
[INFO] tweaked toml for crates.io crate lark-unify 0.1.0 written to /workspace/builds/worker-5/source/Cargo.toml
[INFO] running `Command { std: "/workspace/cargo-home/bin/cargo" "+8b72f65b805cbe4c261de45030d663f524f27376" "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" "+8b72f65b805cbe4c261de45030d663f524f27376" "fetch" "--locked" "--manifest-path" "Cargo.toml", kill_on_drop: false }`
[INFO] [stderr]  Downloading crates ...
[INFO] [stderr]   Downloaded lark-collections v0.1.0
[INFO] [stderr]   Downloaded lark-debug-with v0.1.0
[INFO] running `Command { std: "docker" "create" "-v" "/var/lib/crater-agent-workspace/builds/worker-5/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-5/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" "rustops/crates-build-env@sha256:6eabd152ff4036248d66efda456a36cb33d24b7291b33f25f75140726c88da35" "/opt/rustwide/cargo-home/bin/cargo" "+8b72f65b805cbe4c261de45030d663f524f27376" "metadata" "--no-deps" "--format-version=1", kill_on_drop: false }`
[INFO] [stderr] WARNING: Your kernel does not support swap limit capabilities or the cgroup is not mounted. Memory limited without swap.
[INFO] [stdout] e0a6d7c83a93bb3ff3158e7ebb74a66c74553f75239a67c174b52675eae9f99b
[INFO] running `Command { std: "docker" "start" "-a" "e0a6d7c83a93bb3ff3158e7ebb74a66c74553f75239a67c174b52675eae9f99b", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "inspect" "e0a6d7c83a93bb3ff3158e7ebb74a66c74553f75239a67c174b52675eae9f99b", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "e0a6d7c83a93bb3ff3158e7ebb74a66c74553f75239a67c174b52675eae9f99b", kill_on_drop: false }`
[INFO] [stdout] e0a6d7c83a93bb3ff3158e7ebb74a66c74553f75239a67c174b52675eae9f99b
[INFO] running `Command { std: "docker" "create" "-v" "/var/lib/crater-agent-workspace/builds/worker-5/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-5/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" "rustops/crates-build-env@sha256:6eabd152ff4036248d66efda456a36cb33d24b7291b33f25f75140726c88da35" "/opt/rustwide/cargo-home/bin/cargo" "+8b72f65b805cbe4c261de45030d663f524f27376" "check" "--frozen" "--all" "--all-targets" "--message-format=json", kill_on_drop: false }`
[INFO] [stderr] WARNING: Your kernel does not support swap limit capabilities or the cgroup is not mounted. Memory limited without swap.
[INFO] [stdout] f2a8f568f5271446969050a4f38a28f7297c868e3957ab4a2fef8a5df60364a4
[INFO] running `Command { std: "docker" "start" "-a" "f2a8f568f5271446969050a4f38a28f7297c868e3957ab4a2fef8a5df60364a4", kill_on_drop: false }`
[INFO] [stderr]     Blocking waiting for file lock on package cache
[INFO] [stderr]     Checking rustc-hash v1.1.0
[INFO] [stderr]     Checking indexmap v1.6.0
[INFO] [stderr]     Checking lark-debug-with v0.1.0
[INFO] [stderr]     Checking lark-collections v0.1.0
[INFO] [stderr]     Checking lark-unify v0.1.0 (/opt/rustwide/workdir)
[INFO] [stdout] warning: the feature `specialization` is incomplete and may not be safe to use and/or cause compiler crashes
[INFO] [stdout]  --> src/lib.rs:2:12
[INFO] [stdout]   |
[INFO] [stdout] 2 | #![feature(specialization)]
[INFO] [stdout]   |            ^^^^^^^^^^^^^^
[INFO] [stdout]   |
[INFO] [stdout]   = note: `#[warn(incomplete_features)]` on by default
[INFO] [stdout]   = note: see issue #31844 <https://github.com/rust-lang/rust/issues/31844> for more information
[INFO] [stdout]   = help: consider using `min_specialization` instead, which is more stable and complete
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: the feature `specialization` is incomplete and may not be safe to use and/or cause compiler crashes
[INFO] [stdout]  --> src/lib.rs:2:12
[INFO] [stdout]   |
[INFO] [stdout] 2 | #![feature(specialization)]
[INFO] [stdout]   |            ^^^^^^^^^^^^^^
[INFO] [stdout]   |
[INFO] [stdout]   = note: `#[warn(incomplete_features)]` on by default
[INFO] [stdout]   = note: see issue #31844 <https://github.com/rust-lang/rust/issues/31844> for more information
[INFO] [stdout]   = help: consider using `min_specialization` instead, which is more stable and complete
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: 1 warning emitted
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: 1 warning emitted
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stderr]     Finished dev [unoptimized + debuginfo] target(s) in 2.06s
[INFO] running `Command { std: "docker" "inspect" "f2a8f568f5271446969050a4f38a28f7297c868e3957ab4a2fef8a5df60364a4", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "f2a8f568f5271446969050a4f38a28f7297c868e3957ab4a2fef8a5df60364a4", kill_on_drop: false }`
[INFO] [stdout] f2a8f568f5271446969050a4f38a28f7297c868e3957ab4a2fef8a5df60364a4