[INFO] fetching crate challenge-prompt 0.2.0...
[INFO] checking challenge-prompt-0.2.0 against try#7b3565da729099dbe807466fcd118fb2815986e0 for pr-81789
[INFO] extracting crate challenge-prompt 0.2.0 into /workspace/builds/worker-2/source
[INFO] validating manifest of crates.io crate challenge-prompt 0.2.0 on toolchain 7b3565da729099dbe807466fcd118fb2815986e0
[INFO] running `Command { std: "/workspace/cargo-home/bin/cargo" "+7b3565da729099dbe807466fcd118fb2815986e0" "metadata" "--manifest-path" "Cargo.toml" "--no-deps", kill_on_drop: false }`
[INFO] started tweaking crates.io crate challenge-prompt 0.2.0
[INFO] finished tweaking crates.io crate challenge-prompt 0.2.0
[INFO] tweaked toml for crates.io crate challenge-prompt 0.2.0 written to /workspace/builds/worker-2/source/Cargo.toml
[INFO] running `Command { std: "/workspace/cargo-home/bin/cargo" "+7b3565da729099dbe807466fcd118fb2815986e0" "generate-lockfile" "--manifest-path" "Cargo.toml" "-Zno-index-update", kill_on_drop: false }`
[INFO] running `Command { std: "/workspace/cargo-home/bin/cargo" "+7b3565da729099dbe807466fcd118fb2815986e0" "fetch" "--locked" "--manifest-path" "Cargo.toml", kill_on_drop: false }`
[INFO] [stderr]  Downloading crates ...
[INFO] [stderr]   Downloaded predicates-core v0.9.0
[INFO] [stderr]   Downloaded assert_cmd v0.9.1
[INFO] [stderr]   Downloaded predicates v0.9.1
[INFO] [stderr]   Downloaded predicates-tree v0.9.0
[INFO] running `Command { std: "docker" "create" "-v" "/var/lib/crater-agent-workspace/builds/worker-2/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-2/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" "ghcr.io/rust-lang/crates-build-env/linux@sha256:20528e8c29e4536546f0102ce88568b16ea7538393a33fcca951030f7af10457" "/opt/rustwide/cargo-home/bin/cargo" "+7b3565da729099dbe807466fcd118fb2815986e0" "metadata" "--no-deps" "--format-version=1", 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] 52c7afd1faf5bf6b3222a5c006cf75f8f19efad1599faf48e33cabd2611d1572
[INFO] running `Command { std: "docker" "start" "-a" "52c7afd1faf5bf6b3222a5c006cf75f8f19efad1599faf48e33cabd2611d1572", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "inspect" "52c7afd1faf5bf6b3222a5c006cf75f8f19efad1599faf48e33cabd2611d1572", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "52c7afd1faf5bf6b3222a5c006cf75f8f19efad1599faf48e33cabd2611d1572", kill_on_drop: false }`
[INFO] [stdout] 52c7afd1faf5bf6b3222a5c006cf75f8f19efad1599faf48e33cabd2611d1572
[INFO] running `Command { std: "docker" "create" "-v" "/var/lib/crater-agent-workspace/builds/worker-2/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-2/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" "ghcr.io/rust-lang/crates-build-env/linux@sha256:20528e8c29e4536546f0102ce88568b16ea7538393a33fcca951030f7af10457" "/opt/rustwide/cargo-home/bin/cargo" "+7b3565da729099dbe807466fcd118fb2815986e0" "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] c091af45e5b69363bc396f42997ae2b52d072cc88fbc10559c6c59a2515d2db0
[INFO] running `Command { std: "docker" "start" "-a" "c091af45e5b69363bc396f42997ae2b52d072cc88fbc10559c6c59a2515d2db0", kill_on_drop: false }`
[INFO] [stderr]    Compiling serde v1.0.125
[INFO] [stderr]     Checking predicates-core v0.9.0
[INFO] [stderr]    Compiling escargot v0.3.1
[INFO] [stderr]     Checking regex-syntax v0.6.23
[INFO] [stderr]     Checking normalize-line-endings v0.2.2
[INFO] [stderr]     Checking treeline v0.1.0
[INFO] [stderr]     Checking difference v2.0.0
[INFO] [stderr]    Compiling num-traits v0.2.14
[INFO] [stderr]    Compiling proc-macro2 v1.0.26
[INFO] [stderr]     Checking challenge-prompt v0.2.0 (/opt/rustwide/workdir)
[INFO] [stdout] warning: the item `rand` is imported redundantly
[INFO] [stdout]   --> src/lib.rs:55:13
[INFO] [stdout]    |
[INFO] [stdout] 40 | extern crate rand;
[INFO] [stdout]    | ------------------ the item `rand` is already imported here
[INFO] [stdout] ...
[INFO] [stdout] 55 |         use rand;
[INFO] [stdout]    |             ^^^^
[INFO] [stdout]    |
[INFO] [stdout]    = note: `#[warn(unused_imports)]` on by default
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stderr]     Checking predicates-tree v0.9.0
[INFO] [stdout] warning: 1 warning emitted
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stderr]    Compiling quote v1.0.9
[INFO] [stderr]    Compiling syn v1.0.70
[INFO] [stderr]     Checking float-cmp v0.4.0
[INFO] [stderr]     Checking regex v1.4.5
[INFO] [stderr]     Checking predicates v0.9.1
[INFO] [stderr]    Compiling serde_derive v1.0.125
[INFO] [stderr]     Checking serde_json v1.0.64
[INFO] [stderr]     Checking assert_cmd v0.9.1
[INFO] [stdout] warning: the item `rand` is imported redundantly
[INFO] [stdout]   --> src/lib.rs:55:13
[INFO] [stdout]    |
[INFO] [stdout] 40 | extern crate rand;
[INFO] [stdout]    | ------------------ the item `rand` is already imported here
[INFO] [stdout] ...
[INFO] [stdout] 55 |         use rand;
[INFO] [stdout]    |             ^^^^
[INFO] [stdout]    |
[INFO] [stdout]    = note: `#[warn(unused_imports)]` on by default
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: 1 warning emitted
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stderr]     Finished dev [unoptimized + debuginfo] target(s) in 15.36s
[INFO] running `Command { std: "docker" "inspect" "c091af45e5b69363bc396f42997ae2b52d072cc88fbc10559c6c59a2515d2db0", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "c091af45e5b69363bc396f42997ae2b52d072cc88fbc10559c6c59a2515d2db0", kill_on_drop: false }`
[INFO] [stdout] c091af45e5b69363bc396f42997ae2b52d072cc88fbc10559c6c59a2515d2db0