[INFO] fetching crate veb-rs 0.1.1...
[INFO] checking veb-rs-0.1.1 against master#4fa76a4a7742bb9c1febe33019f5a9e7e4839a65 for pr-83744
[INFO] extracting crate veb-rs 0.1.1 into /workspace/builds/worker-7/source
[INFO] validating manifest of crates.io crate veb-rs 0.1.1 on toolchain 4fa76a4a7742bb9c1febe33019f5a9e7e4839a65
[INFO] running `Command { std: "/workspace/cargo-home/bin/cargo" "+4fa76a4a7742bb9c1febe33019f5a9e7e4839a65" "metadata" "--manifest-path" "Cargo.toml" "--no-deps", kill_on_drop: false }`
[INFO] started tweaking crates.io crate veb-rs 0.1.1
[INFO] finished tweaking crates.io crate veb-rs 0.1.1
[INFO] tweaked toml for crates.io crate veb-rs 0.1.1 written to /workspace/builds/worker-7/source/Cargo.toml
[INFO] running `Command { std: "/workspace/cargo-home/bin/cargo" "+4fa76a4a7742bb9c1febe33019f5a9e7e4839a65" "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" "+4fa76a4a7742bb9c1febe33019f5a9e7e4839a65" "fetch" "--locked" "--manifest-path" "Cargo.toml", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "create" "-v" "/var/lib/crater-agent-workspace/builds/worker-7/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-7/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:c46a2d1a26fb48b37929c74ca49dd9409f2375a0a3bdb8fe07617f3ffccaa889" "/opt/rustwide/cargo-home/bin/cargo" "+4fa76a4a7742bb9c1febe33019f5a9e7e4839a65" "metadata" "--no-deps" "--format-version=1", kill_on_drop: false }`
[INFO] [stdout] d4052e35310346ba35fc5f356b08d88462fe8d8746c3b00d8a5be2076ed1d9f4
[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" "d4052e35310346ba35fc5f356b08d88462fe8d8746c3b00d8a5be2076ed1d9f4", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "inspect" "d4052e35310346ba35fc5f356b08d88462fe8d8746c3b00d8a5be2076ed1d9f4", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "d4052e35310346ba35fc5f356b08d88462fe8d8746c3b00d8a5be2076ed1d9f4", kill_on_drop: false }`
[INFO] [stdout] d4052e35310346ba35fc5f356b08d88462fe8d8746c3b00d8a5be2076ed1d9f4
[INFO] running `Command { std: "docker" "create" "-v" "/var/lib/crater-agent-workspace/builds/worker-7/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-7/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:c46a2d1a26fb48b37929c74ca49dd9409f2375a0a3bdb8fe07617f3ffccaa889" "/opt/rustwide/cargo-home/bin/cargo" "+4fa76a4a7742bb9c1febe33019f5a9e7e4839a65" "check" "--frozen" "--all" "--all-targets" "--message-format=json", kill_on_drop: false }`
[INFO] [stdout] 0e6e5f765dd8763e6bc9d8f4ac05f9fbc124b84666ff19ecc30795e943f93e9b
[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" "0e6e5f765dd8763e6bc9d8f4ac05f9fbc124b84666ff19ecc30795e943f93e9b", kill_on_drop: false }`
[INFO] [stderr]     Checking veb-rs v0.1.1 (/opt/rustwide/workdir)
[INFO] [stdout] warning: variable does not need to be mutable
[INFO] [stdout]    --> src/lib.rs:254:21
[INFO] [stdout]     |
[INFO] [stdout] 254 |                 let mut subtree = &mut self.children[idx as usize];
[INFO] [stdout]     |                     ----^^^^^^^
[INFO] [stdout]     |                     |
[INFO] [stdout]     |                     help: remove this `mut`
[INFO] [stdout]     |
[INFO] [stdout]     = note: `#[warn(unused_mut)]` on by default
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: variable does not need to be mutable
[INFO] [stdout]    --> src/lib.rs:254:21
[INFO] [stdout]     |
[INFO] [stdout] 254 |                 let mut subtree = &mut self.children[idx as usize];
[INFO] [stdout]     |                     ----^^^^^^^
[INFO] [stdout]     |                     |
[INFO] [stdout]     |                     help: remove this `mut`
[INFO] [stdout]     |
[INFO] [stdout]     = note: `#[warn(unused_mut)]` on by default
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused return value of `std::mem::replace` that must be used
[INFO] [stdout]    --> src/lib.rs:217:21
[INFO] [stdout]     |
[INFO] [stdout] 217 |                     mem::replace(subtree, Some(new_tree));
[INFO] [stdout]     |                     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
[INFO] [stdout]     |
[INFO] [stdout]     = note: `#[warn(unused_must_use)]` on by default
[INFO] [stdout]     = note: if you don't need the old value, you can just assign the new value directly
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused return value of `std::mem::replace` that must be used
[INFO] [stdout]    --> src/lib.rs:217:21
[INFO] [stdout]     |
[INFO] [stdout] 217 |                     mem::replace(subtree, Some(new_tree));
[INFO] [stdout]     |                     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
[INFO] [stdout]     |
[INFO] [stdout]     = note: `#[warn(unused_must_use)]` on by default
[INFO] [stdout]     = note: if you don't need the old value, you can just assign the new value directly
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: 2 warnings emitted
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stderr]     Finished dev [unoptimized + debuginfo] target(s) in 0.63s
[INFO] [stdout] warning: 2 warnings emitted
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] running `Command { std: "docker" "inspect" "0e6e5f765dd8763e6bc9d8f4ac05f9fbc124b84666ff19ecc30795e943f93e9b", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "0e6e5f765dd8763e6bc9d8f4ac05f9fbc124b84666ff19ecc30795e943f93e9b", kill_on_drop: false }`
[INFO] [stdout] 0e6e5f765dd8763e6bc9d8f4ac05f9fbc124b84666ff19ecc30795e943f93e9b