[INFO] fetching crate cow_vec_item 0.5.0...
[INFO] testing cow_vec_item-0.5.0 against 1.49.0 for beta-1.50-1
[INFO] extracting crate cow_vec_item 0.5.0 into /workspace/builds/worker-4/source
[INFO] validating manifest of crates.io crate cow_vec_item 0.5.0 on toolchain 1.49.0
[INFO] running `Command { std: "/workspace/cargo-home/bin/cargo" "+1.49.0" "read-manifest" "--manifest-path" "Cargo.toml", kill_on_drop: false }`
[INFO] started tweaking crates.io crate cow_vec_item 0.5.0
[INFO] finished tweaking crates.io crate cow_vec_item 0.5.0
[INFO] tweaked toml for crates.io crate cow_vec_item 0.5.0 written to /workspace/builds/worker-4/source/Cargo.toml
[INFO] running `Command { std: "/workspace/cargo-home/bin/cargo" "+1.49.0" "generate-lockfile" "--manifest-path" "Cargo.toml" "-Zno-index-update", kill_on_drop: false }`
[INFO] running `Command { std: "/workspace/cargo-home/bin/cargo" "+1.49.0" "fetch" "--locked" "--manifest-path" "Cargo.toml", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "create" "-v" "/var/lib/crater-agent-workspace/builds/worker-4/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-4/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:b8eeb62f26c39b23691079a6cb6de528d8e88b4d71a8f6b1d30f8ba7d9c16de9" "/opt/rustwide/cargo-home/bin/cargo" "+1.49.0" "metadata" "--no-deps" "--format-version=1", kill_on_drop: false }`
[INFO] [stdout] 3ad6ec302f9a484191017f56e2d7f22075df4deac2291bc2cac309e52cc31d1e
[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" "3ad6ec302f9a484191017f56e2d7f22075df4deac2291bc2cac309e52cc31d1e", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "inspect" "3ad6ec302f9a484191017f56e2d7f22075df4deac2291bc2cac309e52cc31d1e", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "3ad6ec302f9a484191017f56e2d7f22075df4deac2291bc2cac309e52cc31d1e", kill_on_drop: false }`
[INFO] [stdout] 3ad6ec302f9a484191017f56e2d7f22075df4deac2291bc2cac309e52cc31d1e
[INFO] running `Command { std: "docker" "create" "-v" "/var/lib/crater-agent-workspace/builds/worker-4/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-4/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" "rustops/crates-build-env@sha256:b8eeb62f26c39b23691079a6cb6de528d8e88b4d71a8f6b1d30f8ba7d9c16de9" "/opt/rustwide/cargo-home/bin/cargo" "+1.49.0" "build" "--frozen" "--message-format=json", kill_on_drop: false }`
[INFO] [stdout] 0d3062a32a1d0c37d6b8f401d9c5f78294d7519e567449995c915512d32fbd3a
[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" "0d3062a32a1d0c37d6b8f401d9c5f78294d7519e567449995c915512d32fbd3a", kill_on_drop: false }`
[INFO] [stderr]    Compiling cow_vec_item v0.5.0 (/opt/rustwide/workdir)
[INFO] [stdout] warning: unnecessary parentheses around block return value
[INFO] [stdout]    --> src/lib.rs:232:19
[INFO] [stdout]     |
[INFO] [stdout] 232 |         *unsafe { (&mut *self.bad_wrapper_use_detector) } = WrapperState::Dead;
[INFO] [stdout]     |                   ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: remove these parentheses
[INFO] [stdout]     |
[INFO] [stdout] note: the lint level is defined here
[INFO] [stdout]    --> src/lib.rs:2:9
[INFO] [stdout]     |
[INFO] [stdout] 2   | #![deny(warnings)]
[INFO] [stdout]     |         ^^^^^^^^
[INFO] [stdout]     = note: `#[warn(unused_parens)]` implied by `#[warn(warnings)]`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unnecessary parentheses around block return value
[INFO] [stdout]    --> src/lib.rs:546:22
[INFO] [stdout]     |
[INFO] [stdout] 546 |         if *unsafe { (&*self.bad_wrapper_use_detector) } != WrapperState::Dead {
[INFO] [stdout]     |                      ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: remove these parentheses
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unnecessary parentheses around block return value
[INFO] [stdout]    --> src/lib.rs:581:22
[INFO] [stdout]     |
[INFO] [stdout] 581 |         if *unsafe { (&*self.bad_wrapper_use_detector) } != WrapperState::Dead {
[INFO] [stdout]     |                      ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: remove these parentheses
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: 3 warnings emitted
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stderr]     Finished dev [unoptimized + debuginfo] target(s) in 0.80s
[INFO] running `Command { std: "docker" "inspect" "0d3062a32a1d0c37d6b8f401d9c5f78294d7519e567449995c915512d32fbd3a", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "0d3062a32a1d0c37d6b8f401d9c5f78294d7519e567449995c915512d32fbd3a", kill_on_drop: false }`
[INFO] [stdout] 0d3062a32a1d0c37d6b8f401d9c5f78294d7519e567449995c915512d32fbd3a
[INFO] running `Command { std: "docker" "create" "-v" "/var/lib/crater-agent-workspace/builds/worker-4/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-4/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" "rustops/crates-build-env@sha256:b8eeb62f26c39b23691079a6cb6de528d8e88b4d71a8f6b1d30f8ba7d9c16de9" "/opt/rustwide/cargo-home/bin/cargo" "+1.49.0" "test" "--frozen" "--no-run" "--message-format=json", kill_on_drop: false }`
[INFO] [stdout] 6ee2f509bc001d3bc61aff2988de8b43be5a44a964e2b68566f1113ecd22b546
[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" "6ee2f509bc001d3bc61aff2988de8b43be5a44a964e2b68566f1113ecd22b546", kill_on_drop: false }`
[INFO] [stdout] warning: unnecessary parentheses around block return value
[INFO] [stdout]    --> src/lib.rs:232:19
[INFO] [stdout]     |
[INFO] [stdout] 232 |         *unsafe { (&mut *self.bad_wrapper_use_detector) } = WrapperState::Dead;
[INFO] [stdout]     |                   ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: remove these parentheses
[INFO] [stdout]     |
[INFO] [stdout] note: the lint level is defined here
[INFO] [stdout]    --> src/lib.rs:2:9
[INFO] [stdout]     |
[INFO] [stdout] 2   | #![deny(warnings)]
[INFO] [stdout]     |         ^^^^^^^^
[INFO] [stdout]     = note: `#[warn(unused_parens)]` implied by `#[warn(warnings)]`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stderr]    Compiling cow_vec_item v0.5.0 (/opt/rustwide/workdir)
[INFO] [stdout] warning: unnecessary parentheses around block return value
[INFO] [stdout]    --> src/lib.rs:546:22
[INFO] [stdout]     |
[INFO] [stdout] 546 |         if *unsafe { (&*self.bad_wrapper_use_detector) } != WrapperState::Dead {
[INFO] [stdout]     |                      ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: remove these parentheses
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unnecessary parentheses around block return value
[INFO] [stdout]    --> src/lib.rs:581:22
[INFO] [stdout]     |
[INFO] [stdout] 581 |         if *unsafe { (&*self.bad_wrapper_use_detector) } != WrapperState::Dead {
[INFO] [stdout]     |                      ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: remove these parentheses
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: 3 warnings emitted
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] error[E0554]: `#![feature]` may not be used on the stable release channel
[INFO] [stdout]  --> src/lib.rs:3:19
[INFO] [stdout]   |
[INFO] [stdout] 3 | #![cfg_attr(test, feature(test))]
[INFO] [stdout]   |                   ^^^^^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unnecessary parentheses around block return value
[INFO] [stdout]    --> src/lib.rs:232:19
[INFO] [stdout]     |
[INFO] [stdout] 232 |         *unsafe { (&mut *self.bad_wrapper_use_detector) } = WrapperState::Dead;
[INFO] [stdout]     |                   ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: remove these parentheses
[INFO] [stdout]     |
[INFO] [stdout] note: the lint level is defined here
[INFO] [stdout]    --> src/lib.rs:2:9
[INFO] [stdout]     |
[INFO] [stdout] 2   | #![deny(warnings)]
[INFO] [stdout]     |         ^^^^^^^^
[INFO] [stdout]     = note: `#[warn(unused_parens)]` implied by `#[warn(warnings)]`
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unnecessary parentheses around block return value
[INFO] [stdout]    --> src/lib.rs:546:22
[INFO] [stdout]     |
[INFO] [stdout] 546 |         if *unsafe { (&*self.bad_wrapper_use_detector) } != WrapperState::Dead {
[INFO] [stdout]     |                      ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: remove these parentheses
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unnecessary parentheses around block return value
[INFO] [stdout]    --> src/lib.rs:581:22
[INFO] [stdout]     |
[INFO] [stdout] 581 |         if *unsafe { (&*self.bad_wrapper_use_detector) } != WrapperState::Dead {
[INFO] [stdout]     |                      ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: remove these parentheses
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] error: aborting due to previous error; 3 warnings emitted
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] For more information about this error, try `rustc --explain E0554`.
[INFO] [stdout] 
[INFO] [stderr] error: could not compile `cow_vec_item`
[INFO] [stderr] 
[INFO] [stderr] To learn more, run the command again with --verbose.
[INFO] running `Command { std: "docker" "inspect" "6ee2f509bc001d3bc61aff2988de8b43be5a44a964e2b68566f1113ecd22b546", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "6ee2f509bc001d3bc61aff2988de8b43be5a44a964e2b68566f1113ecd22b546", kill_on_drop: false }`
[INFO] [stdout] 6ee2f509bc001d3bc61aff2988de8b43be5a44a964e2b68566f1113ecd22b546