[INFO] cloning repository https://github.com/wzhd/ustcp
[INFO] running `Command { std: "git" "-c" "credential.helper=" "-c" "credential.helper=/workspace/cargo-home/bin/git-credential-null" "clone" "--bare" "https://github.com/wzhd/ustcp" "/workspace/cache/git-repos/https%3A%2F%2Fgithub.com%2Fwzhd%2Fustcp", kill_on_drop: false }`
[INFO] [stderr] Cloning into bare repository '/workspace/cache/git-repos/https%3A%2F%2Fgithub.com%2Fwzhd%2Fustcp'...
[INFO] running `Command { std: "git" "rev-parse" "HEAD", kill_on_drop: false }`
[INFO] [stdout] 915bda49ce7fd7f9ba9e265aa53aa235fabf895e
[INFO] checking wzhd/ustcp against master#4d0dd02ee07bddad9136f95c9f7846ebf3eb3fc5 for pr-81174
[INFO] running `Command { std: "git" "clone" "/workspace/cache/git-repos/https%3A%2F%2Fgithub.com%2Fwzhd%2Fustcp" "/workspace/builds/worker-1/source", kill_on_drop: false }`
[INFO] [stderr] Cloning into '/workspace/builds/worker-1/source'...
[INFO] [stderr] done.
[INFO] validating manifest of git repo https://github.com/wzhd/ustcp on toolchain 4d0dd02ee07bddad9136f95c9f7846ebf3eb3fc5
[INFO] running `Command { std: "/workspace/cargo-home/bin/cargo" "+4d0dd02ee07bddad9136f95c9f7846ebf3eb3fc5" "metadata" "--manifest-path" "Cargo.toml" "--no-deps", kill_on_drop: false }`
[INFO] started tweaking git repo https://github.com/wzhd/ustcp
[INFO] finished tweaking git repo https://github.com/wzhd/ustcp
[INFO] tweaked toml for git repo https://github.com/wzhd/ustcp written to /workspace/builds/worker-1/source/Cargo.toml
[INFO] crate git repo https://github.com/wzhd/ustcp already has a lockfile, it will not be regenerated
[INFO] running `Command { std: "/workspace/cargo-home/bin/cargo" "+4d0dd02ee07bddad9136f95c9f7846ebf3eb3fc5" "fetch" "--locked" "--manifest-path" "Cargo.toml", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "create" "-v" "/var/lib/crater-agent-workspace/builds/worker-1/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-1/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@sha256:21f1ed92105a0ef9b0d27ad8bdeb7f36f9f01ac17fffe3a3f3dc5241fc25d8f4" "/opt/rustwide/cargo-home/bin/cargo" "+4d0dd02ee07bddad9136f95c9f7846ebf3eb3fc5" "metadata" "--no-deps" "--format-version=1", kill_on_drop: false }`
[INFO] [stdout] ef7282b92f260198eb955d9e25604fc007c4c9590892bada52f1113a1f7614fb
[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" "ef7282b92f260198eb955d9e25604fc007c4c9590892bada52f1113a1f7614fb", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "inspect" "ef7282b92f260198eb955d9e25604fc007c4c9590892bada52f1113a1f7614fb", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "ef7282b92f260198eb955d9e25604fc007c4c9590892bada52f1113a1f7614fb", kill_on_drop: false }`
[INFO] [stdout] ef7282b92f260198eb955d9e25604fc007c4c9590892bada52f1113a1f7614fb
[INFO] running `Command { std: "docker" "create" "-v" "/var/lib/crater-agent-workspace/builds/worker-1/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-1/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@sha256:21f1ed92105a0ef9b0d27ad8bdeb7f36f9f01ac17fffe3a3f3dc5241fc25d8f4" "/opt/rustwide/cargo-home/bin/cargo" "+4d0dd02ee07bddad9136f95c9f7846ebf3eb3fc5" "check" "--frozen" "--all" "--all-targets" "--message-format=json", kill_on_drop: false }`
[INFO] [stdout] ebe0f04d6a67b82a857146c34a62e836b4e4f85de810967d891f4d57e3b22cc4
[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" "ebe0f04d6a67b82a857146c34a62e836b4e4f85de810967d891f4d57e3b22cc4", kill_on_drop: false }`
[INFO] [stderr]    Compiling libc v0.2.69
[INFO] [stderr]    Compiling proc-macro2 v1.0.10
[INFO] [stderr]    Compiling syn v1.0.18
[INFO] [stderr]     Checking regex-syntax v0.6.17
[INFO] [stderr]     Checking smallvec v1.4.0
[INFO] [stderr]     Checking managed v0.7.1
[INFO] [stderr]     Checking unicode-width v0.1.7
[INFO] [stderr]    Compiling cc v1.0.52
[INFO] [stderr]    Compiling proc-macro-nested v0.1.4
[INFO] [stderr]     Checking futures-sink v0.3.4
[INFO] [stderr]    Compiling proc-macro-hack v0.5.15
[INFO] [stderr]    Compiling serde v1.0.106
[INFO] [stderr]    Compiling ryu v1.0.4
[INFO] [stderr]     Checking pin-utils v0.1.0
[INFO] [stderr]     Checking ioctl-sys v0.5.2
[INFO] [stderr]    Compiling argh_shared v0.1.1
[INFO] [stderr]     Checking ansi_term v0.11.0
[INFO] [stderr]     Checking trilock v0.1.0 (https://github.com/wzhd/trilock.git#dc5b657f)
[INFO] [stderr]     Checking tracing-core v0.1.10
[INFO] [stderr]     Checking sharded-slab v0.0.9
[INFO] [stderr]     Checking futures-channel v0.3.4
[INFO] [stderr]     Checking getopts v0.2.21
[INFO] [stderr]     Checking unicode-normalization v0.1.12
[INFO] [stderr]     Checking log v0.3.9
[INFO] [stderr]     Checking tracing-log v0.1.1
[INFO] [stderr]    Compiling backtrace-sys v0.1.36
[INFO] [stderr]    Compiling quote v1.0.3
[INFO] [stderr]     Checking idna v0.1.5
[INFO] [stderr]     Checking atty v0.2.14
[INFO] [stderr]     Checking smoltcp v0.6.0 (/opt/rustwide/workdir/ustcp)
[INFO] [stderr]     Checking rand v0.4.6
[INFO] [stderr]     Checking iovec v0.1.4
[INFO] [stderr]     Checking net2 v0.2.33
[INFO] [stderr]     Checking num_cpus v1.13.0
[INFO] [stderr]     Checking time v0.1.43
[INFO] [stderr]     Checking mio v0.6.21
[INFO] [stderr]     Checking chrono v0.4.11
[INFO] [stderr]     Checking url v1.7.2
[INFO] [stderr]     Checking backtrace v0.3.46
[INFO] [stderr]     Checking rand v0.3.23
[INFO] [stderr]     Checking error-chain v0.11.0
[INFO] [stderr]     Checking tun v0.4.4
[INFO] [stderr]     Checking regex v1.3.7
[INFO] [stderr]     Checking regex-automata v0.1.9
[INFO] [stderr]     Checking matchers v0.0.1
[INFO] [stderr]     Checking env_logger v0.5.13
[INFO] [stderr]     Checking env_logger v0.7.1
[INFO] [stdout] error: unused return value of `core::mem::replace` that must be used
[INFO] [stdout]    --> ustcp/src/iface/neighbor.rs:107:21
[INFO] [stdout]     |
[INFO] [stdout] 107 |                     mem::replace(map, new_btree_map);
[INFO] [stdout]     |                     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
[INFO] [stdout]     |
[INFO] [stdout] note: the lint level is defined here
[INFO] [stdout]    --> ustcp/src/lib.rs:4:98
[INFO] [stdout]     |
[INFO] [stdout] 4   | #![cfg_attr(all(any(feature = "proto-ipv4", feature = "proto-ipv6"), feature = "ethernet"), deny(unused))]
[INFO] [stdout]     |                                                                                                  ^^^^^^
[INFO] [stdout]     = note: `#[deny(unused_must_use)]` implied by `#[deny(unused)]`
[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] error: aborting due to previous error
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stderr] error: could not compile `smoltcp`
[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" "ebe0f04d6a67b82a857146c34a62e836b4e4f85de810967d891f4d57e3b22cc4", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "ebe0f04d6a67b82a857146c34a62e836b4e4f85de810967d891f4d57e3b22cc4", kill_on_drop: false }`
[INFO] [stdout] ebe0f04d6a67b82a857146c34a62e836b4e4f85de810967d891f4d57e3b22cc4