[INFO] fetching crate convec 2.0.1...
[INFO] checking convec-2.0.1 against try#b1cc2963e8346ba1f5afb1edb86dbcf3f9ef0c5f for pr-76104
[INFO] extracting crate convec 2.0.1 into /workspace/builds/worker-2/source
[INFO] validating manifest of crates.io crate convec 2.0.1 on toolchain b1cc2963e8346ba1f5afb1edb86dbcf3f9ef0c5f
[INFO] running `Command { std: "/workspace/cargo-home/bin/cargo" "+b1cc2963e8346ba1f5afb1edb86dbcf3f9ef0c5f" "read-manifest" "--manifest-path" "Cargo.toml", kill_on_drop: false }`
[INFO] started tweaking crates.io crate convec 2.0.1
[INFO] finished tweaking crates.io crate convec 2.0.1
[INFO] tweaked toml for crates.io crate convec 2.0.1 written to /workspace/builds/worker-2/source/Cargo.toml
[INFO] running `Command { std: "/workspace/cargo-home/bin/cargo" "+b1cc2963e8346ba1f5afb1edb86dbcf3f9ef0c5f" "generate-lockfile" "--manifest-path" "Cargo.toml" "-Zno-index-update", kill_on_drop: false }`
[INFO] running `Command { std: "/workspace/cargo-home/bin/cargo" "+b1cc2963e8346ba1f5afb1edb86dbcf3f9ef0c5f" "fetch" "--locked" "--manifest-path" "Cargo.toml", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "create" "-v" "/var/lib/crater-agent-workspace/builds/worker-2/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-2/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:d92eaeed33fa75130ca1ee6c8a01d1ffb62bac859dfdfb3450e3e5d1c0146529" "/opt/rustwide/cargo-home/bin/cargo" "+b1cc2963e8346ba1f5afb1edb86dbcf3f9ef0c5f" "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] 7b130df2272c83ab8de96f5966acb8b0112ec6d1f56f7267c0cb0822a3a5e7f9
[INFO] running `Command { std: "docker" "start" "-a" "7b130df2272c83ab8de96f5966acb8b0112ec6d1f56f7267c0cb0822a3a5e7f9", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "inspect" "7b130df2272c83ab8de96f5966acb8b0112ec6d1f56f7267c0cb0822a3a5e7f9", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "7b130df2272c83ab8de96f5966acb8b0112ec6d1f56f7267c0cb0822a3a5e7f9", kill_on_drop: false }`
[INFO] [stdout] 7b130df2272c83ab8de96f5966acb8b0112ec6d1f56f7267c0cb0822a3a5e7f9
[INFO] running `Command { std: "docker" "create" "-v" "/var/lib/crater-agent-workspace/builds/worker-2/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-2/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:d92eaeed33fa75130ca1ee6c8a01d1ffb62bac859dfdfb3450e3e5d1c0146529" "/opt/rustwide/cargo-home/bin/cargo" "+b1cc2963e8346ba1f5afb1edb86dbcf3f9ef0c5f" "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] b95a4b41135a62def5c29210c5f8728d9aaebb25b8b0526fddaee2ac08654ee9
[INFO] running `Command { std: "docker" "start" "-a" "b95a4b41135a62def5c29210c5f8728d9aaebb25b8b0526fddaee2ac08654ee9", kill_on_drop: false }`
[INFO] [stderr]    Compiling maybe-uninit v2.0.0
[INFO] [stderr]    Compiling libc v0.2.77
[INFO] [stderr]     Checking stable_deref_trait v1.2.0
[INFO] [stderr]     Checking owning_ref v0.3.3
[INFO] [stderr]     Checking smallvec v0.6.13
[INFO] [stderr]     Checking rand v0.4.6
[INFO] [stderr]     Checking parking_lot_core v0.2.14
[INFO] [stderr]     Checking parking_lot v0.4.8
[INFO] [stderr]     Checking convec v2.0.1 (/opt/rustwide/workdir)
[INFO] [stdout] warning: unused return value of `Option::<T>::is_some` that must be used
[INFO] [stdout]    --> src/lib.rs:176:21
[INFO] [stdout]     |
[INFO] [stdout] 176 |                     stack.pop().is_some();
[INFO] [stdout]     |                     ^^^^^^^^^^^^^^^^^^^^^^
[INFO] [stdout]     |
[INFO] [stdout]     = note: `#[warn(unused_must_use)]` on by default
[INFO] [stdout]     = note: if you intended to assert that this has a value, consider `.unwrap()` instead
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: 1 warning emitted
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stderr]     Finished dev [unoptimized + debuginfo] target(s) in 5.54s
[INFO] running `Command { std: "docker" "inspect" "b95a4b41135a62def5c29210c5f8728d9aaebb25b8b0526fddaee2ac08654ee9", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "b95a4b41135a62def5c29210c5f8728d9aaebb25b8b0526fddaee2ac08654ee9", kill_on_drop: false }`
[INFO] [stdout] b95a4b41135a62def5c29210c5f8728d9aaebb25b8b0526fddaee2ac08654ee9