[INFO] fetching crate arc_ast 0.1.0...
[INFO] checking arc_ast-0.1.0 against try#9cfe725f0995b018340c519db1b2f3cf8a7e0631 for pr-81174
[INFO] extracting crate arc_ast 0.1.0 into /workspace/builds/worker-14/source
[INFO] validating manifest of crates.io crate arc_ast 0.1.0 on toolchain 9cfe725f0995b018340c519db1b2f3cf8a7e0631
[INFO] running `Command { std: "/workspace/cargo-home/bin/cargo" "+9cfe725f0995b018340c519db1b2f3cf8a7e0631" "read-manifest" "--manifest-path" "Cargo.toml", kill_on_drop: false }`
[INFO] started tweaking crates.io crate arc_ast 0.1.0
[INFO] finished tweaking crates.io crate arc_ast 0.1.0
[INFO] tweaked toml for crates.io crate arc_ast 0.1.0 written to /workspace/builds/worker-14/source/Cargo.toml
[INFO] running `Command { std: "/workspace/cargo-home/bin/cargo" "+9cfe725f0995b018340c519db1b2f3cf8a7e0631" "generate-lockfile" "--manifest-path" "Cargo.toml" "-Zno-index-update", kill_on_drop: false }`
[INFO] running `Command { std: "/workspace/cargo-home/bin/cargo" "+9cfe725f0995b018340c519db1b2f3cf8a7e0631" "fetch" "--locked" "--manifest-path" "Cargo.toml", kill_on_drop: false }`
[INFO] [stderr]  Downloading crates ...
[INFO] [stderr]   Downloaded arc_number v0.1.1
[INFO] running `Command { std: "docker" "create" "-v" "/var/lib/crater-agent-workspace/builds/worker-14/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-14/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" "+9cfe725f0995b018340c519db1b2f3cf8a7e0631" "metadata" "--no-deps" "--format-version=1", kill_on_drop: false }`
[INFO] [stdout] 0ee6fb8b08f97a06ca6e786192ffaa57472b40c8c836da9839d71b9ca9e651af
[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" "0ee6fb8b08f97a06ca6e786192ffaa57472b40c8c836da9839d71b9ca9e651af", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "inspect" "0ee6fb8b08f97a06ca6e786192ffaa57472b40c8c836da9839d71b9ca9e651af", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "0ee6fb8b08f97a06ca6e786192ffaa57472b40c8c836da9839d71b9ca9e651af", kill_on_drop: false }`
[INFO] [stdout] 0ee6fb8b08f97a06ca6e786192ffaa57472b40c8c836da9839d71b9ca9e651af
[INFO] running `Command { std: "docker" "create" "-v" "/var/lib/crater-agent-workspace/builds/worker-14/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-14/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" "+9cfe725f0995b018340c519db1b2f3cf8a7e0631" "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] dc667749376e8d67097b41f875485208b5227bc3f5c277c8bc05906930d4cecb
[INFO] running `Command { std: "docker" "start" "-a" "dc667749376e8d67097b41f875485208b5227bc3f5c277c8bc05906930d4cecb", kill_on_drop: false }`
[INFO] [stderr]     Checking linked-hash-map v0.5.4
[INFO] [stderr]    Compiling num-traits v0.2.14
[INFO] [stderr]    Compiling num-integer v0.1.44
[INFO] [stderr]    Compiling num-bigint v0.2.6
[INFO] [stderr]    Compiling num-iter v0.1.42
[INFO] [stderr]    Compiling num-complex v0.2.4
[INFO] [stderr]    Compiling num-rational v0.2.4
[INFO] [stderr]    Compiling syn v1.0.60
[INFO] [stderr]     Checking num v0.2.1
[INFO] [stderr]    Compiling serde_derive v1.0.123
[INFO] [stderr]     Checking arc_number v0.1.1
[INFO] [stderr]     Checking arc_ast v0.1.0 (/opt/rustwide/workdir)
[INFO] [stdout] warning: unused import: `ops::IndexMut`
[INFO] [stdout]  --> src/utils/ast_impl.rs:4:34
[INFO] [stdout]   |
[INFO] [stdout] 4 | use std::{collections::VecDeque, ops::IndexMut};
[INFO] [stdout]   |                                  ^^^^^^^^^^^^^
[INFO] [stdout]   |
[INFO] [stdout]   = note: `#[warn(unused_imports)]` on by default
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused import: `Error`
[INFO] [stdout]  --> src/utils/ast_traits.rs:4:33
[INFO] [stdout]   |
[INFO] [stdout] 4 |     fmt::{self, Debug, Display, Error, Formatter},
[INFO] [stdout]   |                                 ^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused import: `std::collections::VecDeque`
[INFO] [stdout]  --> src/lib.rs:9:5
[INFO] [stdout]   |
[INFO] [stdout] 9 | use std::collections::VecDeque;
[INFO] [stdout]   |     ^^^^^^^^^^^^^^^^^^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused import: `ops::IndexMut`
[INFO] [stdout]  --> src/utils/ast_impl.rs:4:34
[INFO] [stdout]   |
[INFO] [stdout] 4 | use std::{collections::VecDeque, ops::IndexMut};
[INFO] [stdout]   |                                  ^^^^^^^^^^^^^
[INFO] [stdout]   |
[INFO] [stdout]   = note: `#[warn(unused_imports)]` on by default
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused import: `Error`
[INFO] [stdout]  --> src/utils/ast_traits.rs:4:33
[INFO] [stdout]   |
[INFO] [stdout] 4 |     fmt::{self, Debug, Display, Error, Formatter},
[INFO] [stdout]   |                                 ^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused import: `std::collections::VecDeque`
[INFO] [stdout]  --> src/lib.rs:9:5
[INFO] [stdout]   |
[INFO] [stdout] 9 | use std::collections::VecDeque;
[INFO] [stdout]   |     ^^^^^^^^^^^^^^^^^^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: variable `length` is assigned to, but never used
[INFO] [stdout]   --> src/utils/ast_traits.rs:71:21
[INFO] [stdout]    |
[INFO] [stdout] 71 |                 let mut length = 0;
[INFO] [stdout]    |                     ^^^^^^^^^^
[INFO] [stdout]    |
[INFO] [stdout]    = note: `#[warn(unused_variables)]` on by default
[INFO] [stdout]    = note: consider using `_length` instead
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: 4 warnings emitted
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: variable `length` is assigned to, but never used
[INFO] [stdout]   --> src/utils/ast_traits.rs:71:21
[INFO] [stdout]    |
[INFO] [stdout] 71 |                 let mut length = 0;
[INFO] [stdout]    |                     ^^^^^^^^^^
[INFO] [stdout]    |
[INFO] [stdout]    = note: `#[warn(unused_variables)]` on by default
[INFO] [stdout]    = note: consider using `_length` instead
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: 4 warnings emitted
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stderr]     Finished dev [unoptimized + debuginfo] target(s) in 22.39s
[INFO] running `Command { std: "docker" "inspect" "dc667749376e8d67097b41f875485208b5227bc3f5c277c8bc05906930d4cecb", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "dc667749376e8d67097b41f875485208b5227bc3f5c277c8bc05906930d4cecb", kill_on_drop: false }`
[INFO] [stdout] dc667749376e8d67097b41f875485208b5227bc3f5c277c8bc05906930d4cecb