[INFO] fetching crate json_flex 0.3.3...
[INFO] checking json_flex-0.3.3 against master#7f5a42b073dc2bee2aa625052eb066ee07072048 for pr-78991
[INFO] extracting crate json_flex 0.3.3 into /workspace/builds/worker-3/source
[INFO] validating manifest of crates.io crate json_flex 0.3.3 on toolchain 7f5a42b073dc2bee2aa625052eb066ee07072048
[INFO] running `Command { std: "/workspace/cargo-home/bin/cargo" "+7f5a42b073dc2bee2aa625052eb066ee07072048" "read-manifest" "--manifest-path" "Cargo.toml", kill_on_drop: false }`
[INFO] started tweaking crates.io crate json_flex 0.3.3
[INFO] finished tweaking crates.io crate json_flex 0.3.3
[INFO] tweaked toml for crates.io crate json_flex 0.3.3 written to /workspace/builds/worker-3/source/Cargo.toml
[INFO] running `Command { std: "/workspace/cargo-home/bin/cargo" "+7f5a42b073dc2bee2aa625052eb066ee07072048" "generate-lockfile" "--manifest-path" "Cargo.toml" "-Zno-index-update", kill_on_drop: false }`
[INFO] running `Command { std: "/workspace/cargo-home/bin/cargo" "+7f5a42b073dc2bee2aa625052eb066ee07072048" "fetch" "--locked" "--manifest-path" "Cargo.toml", kill_on_drop: false }`
[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@sha256:6eabd152ff4036248d66efda456a36cb33d24b7291b33f25f75140726c88da35" "/opt/rustwide/cargo-home/bin/cargo" "+7f5a42b073dc2bee2aa625052eb066ee07072048" "metadata" "--no-deps" "--format-version=1", kill_on_drop: false }`
[INFO] [stdout] 5f05a05c0248a7fe677d1d2ec48b6ffc3bc46d53630cbf8de07111bd23a06863
[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" "5f05a05c0248a7fe677d1d2ec48b6ffc3bc46d53630cbf8de07111bd23a06863", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "inspect" "5f05a05c0248a7fe677d1d2ec48b6ffc3bc46d53630cbf8de07111bd23a06863", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "5f05a05c0248a7fe677d1d2ec48b6ffc3bc46d53630cbf8de07111bd23a06863", kill_on_drop: false }`
[INFO] [stdout] 5f05a05c0248a7fe677d1d2ec48b6ffc3bc46d53630cbf8de07111bd23a06863
[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@sha256:6eabd152ff4036248d66efda456a36cb33d24b7291b33f25f75140726c88da35" "/opt/rustwide/cargo-home/bin/cargo" "+7f5a42b073dc2bee2aa625052eb066ee07072048" "check" "--frozen" "--all" "--all-targets" "--message-format=json", kill_on_drop: false }`
[INFO] [stdout] 1e2274ac4f50acf2197edf3e83b84a9f11fe9a05bfdfe33e70b5c078e9ebdf94
[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" "1e2274ac4f50acf2197edf3e83b84a9f11fe9a05bfdfe33e70b5c078e9ebdf94", kill_on_drop: false }`
[INFO] [stderr]     Blocking waiting for file lock on package cache
[INFO] [stderr]     Checking rustc-serialize v0.3.24
[INFO] [stderr]     Checking json_flex v0.3.3 (/opt/rustwide/workdir)
[INFO] [stdout] warning: unused import: `std::fs::File`
[INFO] [stdout]  --> src/test.rs:4:5
[INFO] [stdout]   |
[INFO] [stdout] 4 | use std::fs::File;
[INFO] [stdout]   |     ^^^^^^^^^^^^^
[INFO] [stdout]   |
[INFO] [stdout]   = note: `#[warn(unused_imports)]` on by default
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: unused import: `std::io::prelude::*`
[INFO] [stdout]  --> src/test.rs:5:5
[INFO] [stdout]   |
[INFO] [stdout] 5 | use std::io::prelude::*;
[INFO] [stdout]   |     ^^^^^^^^^^^^^^^^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stderr]     Finished dev [unoptimized + debuginfo] target(s) in 4.98s
[INFO] [stdout] warning: 2 warnings emitted
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] running `Command { std: "docker" "inspect" "1e2274ac4f50acf2197edf3e83b84a9f11fe9a05bfdfe33e70b5c078e9ebdf94", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "1e2274ac4f50acf2197edf3e83b84a9f11fe9a05bfdfe33e70b5c078e9ebdf94", kill_on_drop: false }`
[INFO] [stdout] 1e2274ac4f50acf2197edf3e83b84a9f11fe9a05bfdfe33e70b5c078e9ebdf94