[INFO] fetching crate dart 0.1.1...
[INFO] checking dart-0.1.1 against try#3e22d1f9053c0fc87629b3c6d5d9567856368e5d for pr-78714
[INFO] extracting crate dart 0.1.1 into /workspace/builds/worker-3/source
[INFO] validating manifest of crates.io crate dart 0.1.1 on toolchain 3e22d1f9053c0fc87629b3c6d5d9567856368e5d
[INFO] running `Command { std: "/workspace/cargo-home/bin/cargo" "+3e22d1f9053c0fc87629b3c6d5d9567856368e5d" "read-manifest" "--manifest-path" "Cargo.toml", kill_on_drop: false }`
[INFO] started tweaking crates.io crate dart 0.1.1
[INFO] removed 0 missing examples
[INFO] finished tweaking crates.io crate dart 0.1.1
[INFO] tweaked toml for crates.io crate dart 0.1.1 written to /workspace/builds/worker-3/source/Cargo.toml
[INFO] crate crates.io crate dart 0.1.1 already has a lockfile, it will not be regenerated
[INFO] running `Command { std: "/workspace/cargo-home/bin/cargo" "+3e22d1f9053c0fc87629b3c6d5d9567856368e5d" "fetch" "--locked" "--manifest-path" "Cargo.toml", kill_on_drop: false }`
[INFO] [stderr]  Downloading crates ...
[INFO] [stderr]   Downloaded dart-sys v2.0.1
[INFO] [stderr]   Downloaded proc-macro-hack-impl v0.4.2
[INFO] [stderr]   Downloaded proc-macro-hack v0.4.2
[INFO] [stderr]   Downloaded mashup v0.1.9
[INFO] [stderr]   Downloaded mashup-impl v0.1.9
[INFO] running `Command { std: "docker" "create" "-v" "/var/lib/crater-agent-workspace/builds/worker-3/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-3/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" "+3e22d1f9053c0fc87629b3c6d5d9567856368e5d" "metadata" "--no-deps" "--format-version=1", kill_on_drop: false }`
[INFO] [stdout] e377cdc1980ed5dabf392c3535b512c4880869f9b24783225ee314fc5bcb8fcf
[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" "e377cdc1980ed5dabf392c3535b512c4880869f9b24783225ee314fc5bcb8fcf", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "inspect" "e377cdc1980ed5dabf392c3535b512c4880869f9b24783225ee314fc5bcb8fcf", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "e377cdc1980ed5dabf392c3535b512c4880869f9b24783225ee314fc5bcb8fcf", kill_on_drop: false }`
[INFO] [stdout] e377cdc1980ed5dabf392c3535b512c4880869f9b24783225ee314fc5bcb8fcf
[INFO] running `Command { std: "docker" "create" "-v" "/var/lib/crater-agent-workspace/builds/worker-3/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-3/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" "+3e22d1f9053c0fc87629b3c6d5d9567856368e5d" "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] 1e2678105f84e8e41a5ce9310500002c72b33e3190659856b9777a8543c4df75
[INFO] running `Command { std: "docker" "start" "-a" "1e2678105f84e8e41a5ce9310500002c72b33e3190659856b9777a8543c4df75", kill_on_drop: false }`
[INFO] [stderr]    Compiling libc v0.2.67
[INFO] [stderr]    Compiling proc-macro-hack-impl v0.4.2
[INFO] [stderr]    Compiling proc-macro2 v0.4.30
[INFO] [stderr]    Compiling dart-sys v2.0.1
[INFO] [stderr]    Compiling proc-macro-hack v0.4.2
[INFO] [stderr]     Checking getrandom v0.1.14
[INFO] [stderr]    Compiling mashup-impl v0.1.9
[INFO] [stderr]     Checking rand_core v0.5.1
[INFO] [stderr]     Checking rand_chacha v0.2.2
[INFO] [stderr]     Checking rand v0.7.3
[INFO] [stderr]     Checking mashup v0.1.9
[INFO] [stderr]     Checking dart v0.1.1 (/opt/rustwide/workdir)
[INFO] [stdout] warning: unused return value of `std::mem::replace` that must be used
[INFO] [stdout]    --> src/dart_types/list.rs:288:21
[INFO] [stdout]     |
[INFO] [stdout] 288 |                     std::mem::replace(self, Item::PossiblyModified(x));
[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: 1 warning emitted
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused return value of `std::mem::replace` that must be used
[INFO] [stdout]    --> src/dart_types/list.rs:288:21
[INFO] [stdout]     |
[INFO] [stdout] 288 |                     std::mem::replace(self, Item::PossiblyModified(x));
[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: 1 warning emitted
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stderr]     Finished dev [unoptimized + debuginfo] target(s) in 11.65s
[INFO] running `Command { std: "docker" "inspect" "1e2678105f84e8e41a5ce9310500002c72b33e3190659856b9777a8543c4df75", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "1e2678105f84e8e41a5ce9310500002c72b33e3190659856b9777a8543c4df75", kill_on_drop: false }`
[INFO] [stdout] 1e2678105f84e8e41a5ce9310500002c72b33e3190659856b9777a8543c4df75