[INFO] fetching crate rbt 0.1.0...
[INFO] checking rbt-0.1.0 against master#385fa9d845dd326c6bbfd58c22244215e431948a for absurd-question-mark-desugar
[INFO] extracting crate rbt 0.1.0 into /workspace/builds/worker-2-tc1/source
[INFO] validating manifest of crates.io crate rbt 0.1.0 on toolchain 385fa9d845dd326c6bbfd58c22244215e431948a
[INFO] running `Command { std: CARGO_HOME="/workspace/cargo-home" RUSTUP_HOME="/workspace/rustup-home" "/workspace/cargo-home/bin/cargo" "+385fa9d845dd326c6bbfd58c22244215e431948a" "metadata" "--manifest-path" "Cargo.toml" "--no-deps", kill_on_drop: false }`
[INFO] started tweaking crates.io crate rbt 0.1.0
[INFO] finished tweaking crates.io crate rbt 0.1.0
[INFO] tweaked toml for crates.io crate rbt 0.1.0 written to /workspace/builds/worker-2-tc1/source/Cargo.toml
[INFO] crate crates.io crate rbt 0.1.0 already has a lockfile, it will not be regenerated
[INFO] running `Command { std: CARGO_HOME="/workspace/cargo-home" RUSTUP_HOME="/workspace/rustup-home" "/workspace/cargo-home/bin/cargo" "+385fa9d845dd326c6bbfd58c22244215e431948a" "fetch" "--manifest-path" "Cargo.toml", kill_on_drop: false }`
[INFO] [stderr]     Updating crates.io index
[INFO] [stderr]  Downloading crates ...
[INFO] [stderr]   Downloaded ppv-lite86 v0.2.9
[INFO] [stderr]   Downloaded shared_memory v0.11.3
[INFO] [stderr]   Downloaded getrandom v0.1.15
[INFO] [stderr]   Downloaded nix v0.19.0
[INFO] [stderr]   Downloaded libc v0.2.79
[INFO] running `Command { std: "docker" "create" "-v" "/var/lib/crater-agent-workspace/builds/worker-2-tc1/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-2-tc1/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@sha256:2788e3201cd34a07e3172128adcd8b3090168a8e3bcc40d7c032b9dda1df7d1c" "/opt/rustwide/cargo-home/bin/cargo" "+385fa9d845dd326c6bbfd58c22244215e431948a" "metadata" "--no-deps" "--format-version=1", kill_on_drop: false }`
[INFO] [stdout] 4140f5ff46b4b78cac7bff463eaf2c1760105e20796d9a77b631558f5c63d7cc
[INFO] running `Command { std: "docker" "start" "-a" "4140f5ff46b4b78cac7bff463eaf2c1760105e20796d9a77b631558f5c63d7cc", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "inspect" "4140f5ff46b4b78cac7bff463eaf2c1760105e20796d9a77b631558f5c63d7cc", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "4140f5ff46b4b78cac7bff463eaf2c1760105e20796d9a77b631558f5c63d7cc", kill_on_drop: false }`
[INFO] [stdout] 4140f5ff46b4b78cac7bff463eaf2c1760105e20796d9a77b631558f5c63d7cc
[INFO] running `Command { std: "docker" "create" "-v" "/var/lib/crater-agent-workspace/builds/worker-2-tc1/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-2-tc1/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" "RUSTDOCFLAGS=--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@sha256:2788e3201cd34a07e3172128adcd8b3090168a8e3bcc40d7c032b9dda1df7d1c" "/opt/rustwide/cargo-home/bin/cargo" "+385fa9d845dd326c6bbfd58c22244215e431948a" "check" "--frozen" "--all" "--all-targets" "--message-format=json", kill_on_drop: false }`
[INFO] [stdout] 406e7a76ac885adb4a65cf24eb7984efff74c55a9a289d12bd40ce026031da25
[INFO] running `Command { std: "docker" "start" "-a" "406e7a76ac885adb4a65cf24eb7984efff74c55a9a289d12bd40ce026031da25", kill_on_drop: false }`
[INFO] [stderr]    Compiling libc v0.2.79
[INFO] [stderr]    Compiling getrandom v0.1.15
[INFO] [stderr]    Compiling bitflags v1.2.1
[INFO] [stderr]     Checking ppv-lite86 v0.2.9
[INFO] [stderr]     Checking quick-error v1.2.3
[INFO] [stderr]     Checking nix v0.19.0
[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 shared_memory v0.11.3
[INFO] [stderr]     Checking rbt v0.1.0 (/opt/rustwide/workdir)
[INFO] [stdout] warning: trait `Topic` is never used
[INFO] [stdout]   --> src/main.rs:44:7
[INFO] [stdout]    |
[INFO] [stdout] 44 | trait Topic {
[INFO] [stdout]    |       ^^^^^
[INFO] [stdout]    |
[INFO] [stdout]    = note: `#[warn(dead_code)]` on by default
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: struct `Root` is never constructed
[INFO] [stdout]   --> src/main.rs:48:8
[INFO] [stdout]    |
[INFO] [stdout] 48 | struct Root {
[INFO] [stdout]    |        ^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: trait `Topic` is never used
[INFO] [stdout]   --> src/main.rs:44:7
[INFO] [stdout]    |
[INFO] [stdout] 44 | trait Topic {
[INFO] [stdout]    |       ^^^^^
[INFO] [stdout]    |
[INFO] [stdout]    = note: `#[warn(dead_code)]` on by default
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: struct `Root` is never constructed
[INFO] [stdout]   --> src/main.rs:48:8
[INFO] [stdout]    |
[INFO] [stdout] 48 | struct Root {
[INFO] [stdout]    |        ^^^^
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: 2 warnings emitted
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: 2 warnings emitted
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stderr]     Finished `dev` profile [unoptimized + debuginfo] target(s) in 4.92s
[INFO] running `Command { std: "docker" "inspect" "406e7a76ac885adb4a65cf24eb7984efff74c55a9a289d12bd40ce026031da25", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "406e7a76ac885adb4a65cf24eb7984efff74c55a9a289d12bd40ce026031da25", kill_on_drop: false }`
[INFO] [stdout] 406e7a76ac885adb4a65cf24eb7984efff74c55a9a289d12bd40ce026031da25